THE JOURNAL 0¥ THE QUEKETT MICROSCOPICAL CLUB. VOL. V 1878-79. 6 : ■UL! Honrjcn : [Published for the Club] DAVID BOGUE, 3, St. Martin's Place, Trafalgar Sqbahe, INDEX. PAGE. Acarina, A. D. Michael on the reproductive system of some of the ... ... ... 223 Actinia parasitica, F. A. Bedwell on the nrticating threads of ... 159 Actinia mesembryantlie7num, F. A. Bedwell on the anatomy of 213 Apparatus for use with small bulls-eye condenser ... ... 75 Autographic process, A. Cottam on a new ... ... ••• Bedwell, F. A., on the urticating threads of Actinia parasitica ... ... 159 ,, On the anatomy of A. mesembryanthemum 213 Bee, J. Hunter on the Queen . . . 127 Brains of Insects, E. T. Newton on constructing models of ... 150 British Sponge, J. G. Waller on a new ... Burch, G. J., on a new micrometer 45 Cooke, Dr. M. C, on the vinegar plant 134 ,, on the Dual Lichen hypothesis ... ... 170 Corals, Di\ Matthews on the history and structure of 105 „ C. Stewarts remarks on Dr. Matthews' paper on 137 Cottam, A., on a new Autographic process ... ... ••• 6 Crisp, F., Influence of diffraction in microscopic vision ... 79 Curves, R. G. West on Lissajous' 38 Development, M. Hartog on Floral 9 Dissecting microscopes, Prof. Huxley on ... ... ... 144 Dissecting microscopes, C. Stewart on ... 147 PAGE. Drosera rotuncMfolia, T. C. White on 266 Dual Lichen hypothesis, Dr. M. C. Cooke on the 170 ,, Discussion on the 206 Edmunds, Dr. J., on an immersion paraboloid ... ... ... 17 Eyes of Insects, B. T. Lowne on the ... ... ... ... 95 Floral development, M. Hartog on ... ... ... ... 9 Floral development of ffelian- thus annuus, W. H. Gilburt on 120 Gilburt, W. H., on the floral development of Heliantlius annuus ... ... ... 120 Glyci2)liagu$ palmifer, A. D. Michael on ... ... ... 29 Green, S., on mounting Insects without pressure ... ... 51 Groves, J. W, on stained animal tissues ... ... ... ... 231 Hartog, M. on Floral development 9 Heliantlius annuus, W. H. Gilburt on the Floral development of 120 History and structure of Corals, Dr. J. Matthews on the ... 105 Histology of the Human skin, C. Stewart on the ... ... 14 Hudson, C. T., on Rotifers ... 161 Hunter, J., on the Queen Bee, &c. 127 Huxley, Prof., on dissecting microscopes ... 144 „ On Physalia ... 192 ,, President's Address, 1S79 250 Immersion paraboloid, Dr. J. Edmunds on an ... ... 17 Influence of diffraction in micro. scopic vision, F. Crisp on the 79 Insects' Brains, E. T. Newton on constructing models of 150 »'£> 6 & 11 INDEX. PAGE. Insects, T. C. White on dissection of 33 „ Eyes, B. T. Lowne on ... 95 Lamp shade, a new ... ... 141 Lee, H., President's Address,1878 87 Lewis, E. T., Testimonial to Lichens, Discussion on . . . Lissajous' curves, R. G. West on ,, „ Discussion on Lowne, B. T., on the eyes of Insects Matthews, Dr. J., on the history and structure of Corals On the Micro-megas- u 102 186 38 67 95 105 167 cope Michael, A. D., on Qlycvphagus paJ/mifer ... ,, On the reproductive system of certain Aca/rina ... Micro-megascope, Di\ J. Mat- thews on a ... ,, Discussion on ,, J. E.Ingpenon 259 Micrometer, G. J. Burch on a new 45 Microscopic vision, F. Crisp, on the influence of diffraction in Mounting Insects without pres- 29 223 167 196 79 sure, S. Green on 51 Newton, E. T., on constructing models of Insects' Brains ... 150 Physalia, Prof. Huxley on ... 192 President's Address — H. Lee, 1878 ... 87 President's Address — Prof. Huxley, 1879 250 PAGE. Proceedings— 11, 63,94, 133, 185,256 Rolfe, C. S., on an improved turn-table Rotifers, C. T. Hudson on Schulze, A., on resolving fine- lined tests Soiree, 1879 Spongilla fluviatalis, J. G. Waller on Stained Animal tissues, J. W. Groves on Stewart, C, on the Histology of the Human skin ,, on Ozokerite or " Black Wax" „ on Dissecting micro- scopes Tests, A. Schultze on resolving fine lined Turn-table, C. S. Rolfe on an improved Variations in Sjjongilla fluvia- talis, J. G. Waller on Yinegar-plaut, Dr. M. C. Cooke on the ... Waller 1 , J. G., on a new British sponge ... ,, On variation in Spon- gilla fluviatalis ... West,R. G., on Lissajous' curves Williams, G , on an apparatus for use with Powell's small bulls-eye condensor ... White, T. C, on Insect dissection ,, On Drosera rotundi- folia ... ... 266 248 164 209 198 53 231 14 147 147 209 248 53 134 1 53 38 75 33 THE JOURNAL OF THE ($ttcluit Hlkrostflpml Club. On a New British Sponge of the Genus Microciona. By J. G. Waller. (Read November 23rd, 1877.) Plates I. II. The Sponge, which I have the pleasure of bringing before you, was found in a deep cleft on the under side of a boulder of the New Red Sandstone, off Paignton, in Torbay, at about the ordinary low tide mark. The locality is well known to our naturalists, both past and present. The Rev. Charles Kingsley, in his " Glaucus," has elo- quently descanted on the abundant riches of the place, which afforded him much enjoyment in the study of natural history. Following the retiring tide, especially if it be at the equinox, you have ample leisure for an examination of those fringes of the rocks where a certain class of sponges are found in considerable quantity. These are for the most part " coating sponges," or those which like to fix themselves in narrow fissures ; and that which I bring before you as yet undescribed and new to our fauna, belongs to the first class, and to the genus established by Dr. Bowerbank, under the name of Microciona. The characters which distinguish the genus are thus set forth in the second volume of the " Spongiadse," p. 7, as having" a common basal membrane, whence spring, at or about right angles to its plane, numerous separate columns of spicula, intermixed with keratode, furnished externally with spicula, which radiate from the columns, at various angles, towards the dermal surface of the sponge." Dr. Bowerbank has tabulated twelve varieties, all of B Z 3. Q. WALLER ON A NEW BRITISH SPONGE which arc distinct and more or less interesting ; and that which he now calls Microciona plumosa has long been known to our naturalists, having been first described by Colonel Montague, who must have been very familiar with Paignton shore, under the name of Spongia plumosa. Here it grows abundantly, often in large patches, of a deep orange-red colour. Most of the genus hitherto described are found to range from a deep yellow to the deepest blood-red, as in M. atrasanguinea ; but that which I am about to describe is of a deep olive green when living, and of a pale olive tint when dry. So in colour it is distinct from all its congeners. But every student of the Spongiadas knows that colour is a variable condition, and one must never rely on its being constant, when only one example has been discovered, as in this instance. Were this, then, the only difference, it could not stand as a variety. Fortu- nately, there is a structural distinction, which leaves this matter in no doubt whatever. Amongst the various forms of retentive spicules, none of the sponges of this genus, at present made known, have the bihamate form common to a large number of the silicious sponges. So, as these are found upon the membranes of the example under consideration, it is clearly a well-marked variety. The small coating sponges, not only belonging to this but to allied genera, well deserve the attention of microscopists ; for without the microscope many would be utterly lost to us ; and all require that instrument to detect and display the minute and curious forms of spicula which are discoverable in their tissue — almost as difficult of resolution, and certainly as interesting, as the markings of the Diatomaceas. Many of the Microciona, with the long flexuous columns of their skeleton, are singularly beautiful objects under the low powers, and cannot fail to interest the most common observer. The sponge before you is but a small portion of that I discovered, but it was with difficulty I obtained it from its narrow secluded habitat. As you see, it covers a piece of the Red Sandstone, very thinly ; its stoutest part not rising above the eighth of an inch, whilst the average thickness is less than half that. Alive it was smooth, slightly undulating, sarcode abundant, neither oscula nor pores very distinct, the former few in number. In the dried condi- tion, the oscula are more easily discernible ; they are dispersed and generally separate, but sometimes two are found together. The skeleton columns are in length intermediate, not being quite so long as in M. plumosa, when the latter is fully developed and they OF THE GENUS MICROCIONA. O occasionally send ont a branch. The basal and dermal membranes are alike in character, being thin and pellucid, both having a network of fine cylindrical spicula, the terminations acutely pointed, and with retentive spicula of the bihamate form, contort and sigmoid, of various sizes, though the smaller must, I think, be regarded as immature in growth. Besides these, are others of the anchorate description, though less in number, yet occasionally abundant. The larger kind is tridentate, palmate, equi-anch orate, with a few biden- tate equi-anchorate. Of this latter is a smaller variety, more slender in character, having the teeth projected outwards somewhat like the barb of an arrow. The interstitial membranes are also provided with the two classes of retentive spicula, at times in considerable quantities, often seen attaching themselves to the larger spicula of the skeleton, showing their office to be that of binding the membranes to it as well as together, thus warranting the term " retentive," which Dr. Bower- 1 bank has given to them. The columns of the skeleton are composed of acuate spicula, more or less spinous, but, like many of the genus, being more pro- nounced at the base. At the apices they often project through the membrane, giving a hispid appearance to the surface when the sponge is dry, but not visible in its living condition. Spicula of a similar character also project at various angles from the columns. Besides these there are smaller spicula attenuato-acuate entirely spined. In calling attention to the analogies with known species, mention has already been made of 31. plumosa in relation to the size of the skeleton columns. The spicula are very similar in character to many of the genus, but those of the skeleton are mostly like to those in M. Jict/t/a, differing, however, from all in having no inflation at the base. The tridentate-palmate form in the membranes resembles that in M. ambigua, and the angulate-bidentate is found in no less than seven out of the twelve species already described. The bihamate forms, which are found alone in this species of the genus are sometimes so abundant on the dermal membrane as to appear closely matted together, especially between the intervals of the apices of the skeleton columns, and are of all sizes, some exceedingly minute, but undoubtedly these must be considered as immature, as before stated. A close examination of the membranes will amply repay the observer in minute structure. There is evidently order in 4 J. G. WALLER ON A NEW BRITISH SrONGE what at first sight would appear to he indiscrimination ; you may- trace the bihamate spicules interlocking with each other, here and there held and hooked by the fluke of an anchorate form, and the more rarely observed bihamate reversed or sigmoid spicule may be seen twining about one of the skeleton, helping to hold on the membranes as well as to keep them together. (Vid. pi. I., fig. 5, 6). The reproductive organs at present remain unknown, as I am not sure if the object seen in some of my preparations are other than small masses of sarcode. None of the so-called gemmules have been found in any of the genus except 31. armata. There are a greater variety of spicula in this species than in any of its class, reminding one very much of those in Halichondria in- crustans, to which the bihamate forms seem to make an alliance. The latter are most abundant in those areas of the dermal membrane which lie between the projecting apices of the skeleton columns, when they sometimes interlace with each other in a curiously compact manner, and it is probable that here the pores would be found, but I could not perceive them. Having thus given a general description of this most interesting species, it is now necessary to give it a name. Of course this is pro- visional, in case it may already have been described by another, or may be amongst those thirty or forty additions which our lamented friend Dr. Bowerbank had made since the publication of his third volume of the " Spongiadaa." Already, indeed, was this example packed with others to be sent for his inspection, when his death occurred. The name I propose has reference to its structural differences which the bihamate spicule gives us, viz., Microciona bihamigera. Following Dr. Bowerbank's formula, the Sponge may be thus tabulated : — Sponge, coating, thin ; colour, when alive, olive green ; dry, a paler tint of the same. Surface smooth when alive, in the dry state somewhat hispid. Oscula dispersed, but sometimestwo together. Pores inconspicuous. Dermal membrane thin, pellucid, spiculous. Spicula cylindrical, each end abruptly pointed, slender ; retentive spicula bihamate, contort and sigmoid, very numerous ; also triden- tate, palmate, equi-anchorate, and a few bidentate equi-anch orate large and small dispersed. Skeleton columns long and sometimes branched. Spicula acuate, spinous, spines more pronounced at the base ; defensive spicula the same ; also shorter ones attenuato- acuate, OF THE GENUS MICROCIOXA. entirely spined. Interstitial membranes tliin and pellucid ; spicula same as dermal membrane. Habitat, Paignton Rocks, Torbay. DESCRIPTION OF PLATES I. AND II. Plate I. Fig. 1. — JMicrociona bihamigera. Sponge fall size, coating a piece of the New Red Sandstone- Fig. 2. — Spicule of skeleton. 400 diam. Fig. 3. — Smaller ditto. 400 diam. Fig. 4. — Cylindrical spicule of dermal membrane. 400 diam. Fig. 5, 6. — Groups of bihamate andanchorate spicules from the membranes. 725 diam. Fig. 7. — Portion of the dermis showing the arrangement of bihamate spicules. 80 diam. Fig. 8. — Tridentate, equi-anchorate, palmate spicule of the membranes. 1150 diam. Fig. 9. — Bidentate ditto. 1150 diam. Fig. 10. — Bihamate ditto. 725 diam. Plate II. Exhibits a section of the sponge at right angles to its surface, showing, arrangement of the skeleton columns. Some of these are dis- rupted from their bases of attachment, a, shows reticulation of dermal membrane, and some spicules projecting through the latter. 80 diam. 6 On the " Autographic " Process of Lithography as applicable to the illustration of scientific papers. By Arthur Cottam, F.R.A.S. {Bead December 28th, 1877.) It will, I doubt not, be readily admitted that the value of many a scientific paper is greatly increased by good illustrative plates. Many papers would be almost unintelligible unless illustrated. And again the value of the illustrations is very much greater when they are drawn by the author of the paper they are intended to illustrate. To have plates drawn by a professional draughtsman is always ex- jDensive work, and unless the draughtsman has some knowledge of the objects to be figured, it is a matter of no little difficulty — some- times almost an impossibility — to explain to him the special features that are to be brought out, and the minute differences and gradations of light and shade upon which the value of a drawing frequently depends. A process that will enable any one who can draw fairly well — and I suppose all microscopists can draw more or less, at all events they should be able to do so — to draw his own figures, and to have them printed in facsimile in any numbers, and at a very small cost, is a process so likely to be valuable to the members of this Club, that I am anxious to introduce the new " Autographic " process to you, as I believe it will be found to possess all these advantages. To explain it, I must briefly describe the ordinary processes of lithography. Drawings on stone are made with a greasy ink, manufactured on purpose, or with lithographic chalk, which is also greasy. The stone, which is very porous, absorbs the grease wherever it is laid upon it. When the drawing is complete, the stone is washed over with gum-water, which soaks into the stone wherever there is no greasy ink or crayon. When the gum is dry, a roller of printing ink is passed over the stone, and the ink adheres to the greasy parts but will not touch the gummed surface, and by renewing the ink any number of impressions can be printed off. A. COTTAM ON AUTOGRAPHIC LITHOGRAPHY, &C. 7 To draw well on stone requires a long apprenticeship, as the draw- ing has to be reversed, and the surface is not easy to work upon. To overcome the difficulty of reversing, there has been a transfer paper in use for a long time, on which a drawing could be made the right way, which could afterwards be transferred by pressure from the paper to the stone, and then be printed from the stone in the usual way. Lithographic stones are of two kinds, some have a smooth face, and others a grained surface. Lithographic chalk can only be used upon the latter kind ; upon a smooth stone a drawing must be made with ink alone. The old transfer paper has a smooth face, and like a smooth stone can only be used for a drawing in ink. The face of the paper is very greasy, is not a good colour, and is almost as difficult to work upon as the stone itself. It has the further disadvantage, that ink lines drawn upon it almost invariably spread in the process of transfer to the stone, and the print is consequently much coarser than the drawing. The " Autographic " Process, which I now wish to introduce to your notice, is simply a transfer paper with a grained instead of a smooth surface. This grained face enables you to draw with the ink as finely as upon the stone, as well as to use crayon for shading, and it has this immense advantage over the smooth paper, that if the ink lines are drawn with ink not too thick, they will be transferred to the stone as finely as they are drawn, the tendency of lines to spread being almost entirely got rid of. The paper is a beautiful colour, and with very little practice is as easy to draw upon as upon ordinary paper. The " Autographic" paper is made for, and is sold by Messrs. Maclure and Macdonald, of " The Turret" Printing Offices, No. 97 f Queen Victoria Street, City. Lithographic Ink is sold in sticks like Indian ink. The proper crayon to use is Lcmercier's u Crayon Copal." I believe both the ink and crayon can be obtained at Barbe's, 90, Regent's Quadrant. A few words as to the modus operandi. The paper must be kept free from grease, and should not be touched with the hand more than necessary, as all greasy finger marks (and the skin is generally more or less greasy) will print. You may outline your work upon the paper with a fine hard pencil, but it should be used lightly. To prepare the ink, heat a saucer over a spirit lamp, and while it is 8 A. COTTAM ON AUTOGRAPHIC LITHOGRAPHY, &C. warm rub the ink upon it ; the heat will dissolve a small portion. Add water to what you have rubbed, but do not rub the stick in water. The ink should not be used too thick, and should work freely. A pen or brush may be used to draw with, but a fine sable brush is by far the better tool. With a brush there is no fear of injuring the surface of the paper, and with a little practice much finer lines can be drawn with a brush than with a pen. The crayon can be best brought to a fine point by rubbing it down on a piece of emery cloth. The drawing should be transferred to stone as soon as convenient after being completed, as the ink seems to lose its virtue after a time. As to cost — a plate the size of our "Proceedings" can be trans- ferred to the stone for about 5s. or 6s., and can then be printed on good plate paper for about 6s. a hundred, including the cost of the paper. 9 On the Investigation op Floral Development. By Marcus M. Hartog, M.A., B.Sc, F.L.S. (Read December 28th, 1877.) (Abstract.) The author commenced with some expression of regret that a subject of such importance should have received so little attention in this country, that the only reference to it in any English text-book was in the latest editions of " Lindley's Introduc- tion to Botany." He recommended its study as of great utility and interest, and proceeded to give some useful hints as to the best methods of procedure. The microscope to be used for the purpose should give clear detail, with powers ranging from 10 to 60 diameters, and must possess freedom from colour ; the simple form was better than the compound, as it gave plenty of working distance and side light, with clearer perception of relief. The pattern specially recommended was one by Arthur Chevalier, which had a heavy, steady stand, and a large stage, and admitted of the magnifier being moved in every direction ; whilst the doublets supplied by that maker an- swered the purpose admirably, giving a very large and flat field of view. The needles most suitable were lance-shaped, suffi- ciently broad at the base, finely tapering towards the point, and sharpened on both edges ; with these, practice only would be needed to carry on the finest dissections. Payer and others recommended early morning light as the best to work with, it being grey, as distinguished from the more coloured rays of evening, and illuminating the object under examination in a horizontal direction, which was very advantageous. The process of working consisted in taking off the parts of the flower one by one to see what lay underneath, and in illustration of the process, the author described the manner in which the flower of the Foxglove should be dissected, in order to trace back its origin to the first appearance as a hemispherical elevation on the 10 M. M. HARTOG ON FLORAL DEVELOPMENT. axis of the inflorescence. In older flowers it was best to begin by making sections of the ovary, and the best types to begin upon were the racemose Corollijiorce, such as the Foxglove and Snapdragon ; a fresh stem should always be taken, as the various parts quickly began to dry up or become flaccid. The best method of preparation for examination under the compound microscope was to make sections and act on them with a solution of caustic potash, after which having washed them they should be mounted in glycerine, when they would be sufficiently transparent. It was, however, the opinion of the author that this class of objects was shown with greater accuracy under the simple microscope than by the compound. In further illustration of his subject he exhibited Chevalier's microscope already mentioned, together with doublets of 1, 2, 3, 5, and 10 lines focus, and a pair of lance-headed dissecting needles. A copy of the Atlas to Payer's " Organogenie Comparee," showing the various stages of the develojmient of the flower in many natural orders, was also placed upon the table for the examination of the members. 11 PROCEEDINGS. August 10th, 1877. — Conversational Meeting The following objects were exhibited : — Tongue of Mouse, injected A Blade of Grass, stained Geophilus longicomis (Snake centipede) Leaf of Dendro-calamus giganteus (Bamboo) Aidacodiscus Kittonii Bladder of Guinea-pig, showing Peyer's Glands Leaf of Drosera rotundifolia ... Graphic Granite, fromPortsay (for distribution) Tingus cardui Parallel Microscope, for camera lucida drawing Foraminifera, from Indian Ocean Cynoglossum sylvatica Graphic Granite, from Scotland Ptyclwdus tooth from chalk Mr. F. W. Andrew. Mr. T. H. Buffham. Mr. F. Enock. Mr. W. H. Gilburt. Mr. H. G. Glasspoole Mr. J. J. Hunter. Mr. Ingpen. Mr. M. Hawkins Johnson. Mr. W. Moginie. >> >» Mr. B. W. Priest Mr. J. W. Reid. Mr. G. J. Smith. >> »> Attendance — Members, 40; Visitors, 3. August 24th 1877.— Ordinary Meeting. J. G. Waller, Esq., in the Chair. The minutes of the preceding meeting were read and confirmed. Mr. A. St. Clair Buxton, Dr. R. C. Croft, Mr. F. Habirshaw, Dr. John Habirshaw, Dr. Parkinson Oates, and Mr. E. B. Turner, were balloted for and duly elected Members of the Club. The following donations, &c, were announced, and the thanks of the Club voted to the Donors: — " The Monthly Microscopical Journal" " Science Gossip." " Proceedings of the Royal Society " " Transactions of the American Medical Association" "Annals of Natural History " "American Journal of Microscopy " " Proceedings of the Belgian Microscopical" Society" from the Publishers. j> '} „ the Society. „ the Association. by purchase, in exchange. from the Society. 12 " Medical Examiner." Weekly ... ... „ the Editor. "Analyst" ... ... ... ... ... „ „ " American Naturalist " ... ... ... in exchange. " Report of the Bristol Naturalists' Society '' from the Society. Photographs of Mr. H. G. Glasspoole and Mr. F. Grayling. Specimens of Drosera rotundifoUa, for dis-") -., p . , tribution ... ... ... ... * Mr. Ingpen described a method of oblique illumination exhibited in the room by Dr. Dickson, of Glasgow. An ordinary bull's-eye condenser was placed with its convex side uppermost and its flat side nearly horizontal, and reflected the light in the same manner as an Amici prism, and with very good effect. It was of great use to know that an appliance like a bull's- e)e, which was almost always at hand, could be turned to such good account. Mr. Ingpen then gave a description of the various forms of camera lucida which had been devised for landscape drawing, and for use with the microscope. First explaining the principles upon which the camera lucida was constructed, he proceeded to describe various forms devifed by Dr Wollaston, Amici, Soemmering, Beale, Nachet, Doyere, Nobert, Chevalier, and others. Particular reference was made to Goring and Pritchard's rnico- graphia (1837, p. 221, " Quekett," on the Microscope, 3rd ed., 1855, pp. 167, 253 ; Carpenter on the Microscope, 5th ed., 1875, p. 127. et. seq. ; " Quarterly Journal of Microscopical Science," vol. viii., p, 156 j and atten- tion was drawn to the utility of the camera lucida, as a check upon " fancy drawing," as offering facilities for making rapid and faithful sketches of living objects, and of cultivating habits of accurate observation. Nearly all the forms described were exhibited in the room. Dr. Cooke said that he had been in the habit of using Nachet's camera lucida almost daily for some years, and found it of the greatest advantage. Any difficulty in seeing the pencil could easily be overcome by using a second lamp, as generally the object was too bright, and the pencil in con- sequence indistinct. He always used a microscope in a fixed position, with the camera attached and ready for use at a moment's notice ; and some care- ful measurements having been made once for all, the sizes of objects ex- amined, and the extent to which they were magnified, could also be recorded with each drawing. ' In answer to a question, Mr. Ingpen said that the difficulty found by many persons in \ising the Wollaston camera was caused by their keeping the eye too far over the prism. Mr. Curties advocated the use of squared paper, as being in some re- spects more convenient than the camera, and said that Mr. Suffolk had expressed a similar opinion. The thanks of the Meeting were voted to Dr. Dickson and Mr. Ingpen for their communications. The Chairman announced the engagements for the ensuing month, and 13 the meeting terminated with a conversazione, at which the following objects were exhibited : Stained stem of Equisetum limosum ... Hydra vulgaris Diatoms shown with bull's-eye condenser Ihoridion lineatum Aulacodiscus Kittonii. 5 rays... Ditto ditto, 8 rays Acari found in a damp mouldy book ... Triceratium septangulatum, illuminated wi polarized light and coloured ground Surirella gemma, under 1-16 object-glass ithl Mr. T. H. Buff ham. Mr. G. Carr. Dr. Dickson. Mr. F. Enock. Mr. Hailes. > > j» Mr. A. H. Halley. Mr. E. M.Nelson. Mr. H. J. Roper. Attendance — Members, 45 ; Visitors, 8. September 14th, 1877. — Conversational Meeting. The following objects were exhibited : — Web of Cinifio atrox Pulex vespertilionis, male and female... Scalariform vessels from Pteris aquilina Phylloxera vastatrix Wing of " Eed Admiral" butterfly Section of Human Fallopian Tube Leaf of Drosera Anglica Laurentian Quart zite from Tona Glands of leaf of Hop... Oral Membrane of Echinus, showing Pedicel- 7 laria, &c ... ... ... •* Human ovum Mr. F. Enock. Mr. H. E. Freeman. Mr. W. H. Gilburt. Mr. H. G. Glasspoole. Mr. A. H. Halley. Mr. J. J. Hunter. Mr. J. E. Ingpen. Mr. M. Hawkins Johnson. Mr. A. Martinelli. Mr. B. W. Priest. Mr. E. Richards. Attendance — Members, 53 ; Visitors, 7. September 28th, 1877. — Ordinary Meeting. Henry Lee, Esq., F.L.S., &c, President, in the Chair. The minutes of the preceding meeting were read and confirmed. The following gentlemen were balloted for and duly elected members of the club : — Mr. John Hagger, Mr. Robert Headley, Mr. Henry Pocklington Mr. Kenneth J. Tarrant, and Mr. Thomas P. Watson. The following donations to the club were announced : — " The Monthly Microscopical Journal" ... from the Publishers. " Science Gossip" ... ... ... „ ,, " Proceedings of the Royal Society" ... ,, Society. 11 The Medical Examiner " (weekly) ... „ Editor. > from the Society. 14 "The Annals of Natural History" ... by purchase. " The American Naturalist" ... ...in exchange. " Proceedings of the Belgian Microscopi- cal Society" Ten slides ... ... ... ... „ Mr. F. Coles. Photographs of Physalis ... ... ,, Dr. Habirshaw. The President said that in addition to the foregoing list, a special gift had been made to the club, which they could not possibly include in the usual vote of thanks to the donors. Mr. Cronch had presented to them a magni- ficent binocular microscope stand, which was placed upon the table before them. Without further enlarging upon its merits, or upon Mr. Crouch's liberality, he would ask them to pass a special vote of thanks for this very valuable present. They would observe that in the box containing the instrument Mr. Crouch had wisely left a number of vacancies for the reception of objectives and various apparatus, and he threw this out as a hint to members that any future donations would be acceptable. A vote of thanks to the donors and a special vote of thanks to Mr. Crouch for his valuable gift were unanimously passed. Mr. Chas. Stewart then delivered an address to the members " On the Histology of the Human Skin." As regained the physical properties of the skin and its general appearance, it might be described as that structure with which the whole surface of the body was invested ; it was flexible, tough, strong, and elastic ; these properties rendered it eminently fitted for the protection of the more delicate structures within ; and being on the surface of the body it likewise had to be sensitive to the touch and to alterations of temperature. It also afforded means by which various waste products were poured out, which, if retained, would be highly injurious to the system. It was not alike all over the body, but might be divided into the common skin which covered most of the surface, and which was more or less covered with hair, and the palma and planta skins of the hands and the feet on which no hair grew. Taking that portion of the skin which formed the chief covering of the body, it was found to be divided into two layers — the Epidermis or scarf skin and the deeper layer known as the Dermis or true skin. The Epidermis was composed almost entirely of minute cells, which had upon their surface a vast number of small spine- like processes. Formerly it was held that these spines were of use for interlocking with those of other cells, but more recently they had been taught that this was not the case, biit that they were opposed to one another ; for his own part, however, he inclined to the belief that the inter- locking was the rule and the opposition the exception. The cells were built up in layers — the outer one being the horny layer and the inner being a living layer known as the " rete-mucosum." Between the two there was a special transitional layer known as " Schon's " layer, and besides this it was exceedingly probable that certain processes of the dermic cells also penetrated amongst the cells of the Epidermis, which also received the delicate nerve fibrilloe that passed into it from the Dermis. Beneath the Epidermis came the Dermis or true skin, and the exceeding 15 toughness of this was due to bundles of fibrous tissue interlacing in every direction, and forming a very deep layer, at the bottom of which fat cells were introduced. These bundles were also surrounded and intermixed with cells, and for the nutrition of the skin there were provided numerous canals and blood vessels, which, like blood vessels everywhere else, were found in positions of least pressure, occupying the spaces between the bundles. Nutriment was thus conveyed, and life was kept up, a fluid was exuded which saturated the cells, and the surplus was drained off by a set of tubes — the lymphatics or drain tubes. Mr. Stewart then proceeded by means of numerous drawings in coloured chalks upon the black board to describe and explain the position and structure of the Sudoriporous and Sebaceous glands and follicles, the general appearance of the sweat gland and its upward spiral course to its outlet through the epidermis being very clearly shown. The complicated structure of the hair follicle was next pointed out, and the Dermic and Epidermic origin of the root sheath — the layers of which it was composed, the structure of the hair itself, together with its means of nutriment, and its erector muscles — were severally explained ; and a short description of the peculiarities of the skin upon the palm and sole — which were chiefly distinguished by tho absence of hair, regularity of the sweat glands, greater size of the papillae, arranged in rows, and different arrangement of the touch corpuscles — brought a highly interesting and instructive address to a close. In addition to the diagrams which were drawn by Mr. Stewart as he proceeded, the sub- ject was further illustrated by numerous preparations exhibited under microscopes in the room. Mr. T. C. White said he had seldom had the pleasure of listening to a more lucid explanation of a complicated subject than that which Mr. Stewart had given them. Mr. Stewart had told them all about the growth of straight hair, but he should like to ask him if he could account for the very curly hair of the negro ? Mr. Stewart was afraid he could not say what was the original cause of the curling of the hair; he had examined the negro's scalp and believed it to be a matter of race. It was a curious fact that in making a section of the scalp the hair follicle was fourd to have a curled direction, so that the whole thing — follicle and hair below the skin, as well as above it — was all curly together. He had a slide in which this peculiarity was well shown. The President said that Mr. Stewart's knowledge was so complete, and his explanations were so clear, that it was always a pleasure to listen to him, and he was quite sure that all present would feel that what they had heard that evening was no exception to the rule. The thanks of the meeting were unanimously voted to Mr. Stewart for his interesting communication. Announcements of meetings, &c, for the ensuing month, were then made, and the proceedings terminated with a conversazione, at which the following objects were exhibited : — Sections of Human Skin ... ... Mr. W. J. Brown. Section of b. adder of Utricular ia vulgaris Mr. T. H. Buff ham. 16 Seed of Honeysuckle ... Arranged Diatoms Pea Blight Fructification of Blechnum spicant Tongue of Eristalis narcissi Wing of Silver Studded Blue Butterfly .. Starch Granules Stictodiscus Buryanus ... Selected Diatoms Aulacodiscas Kittonii ... Sections and preparations of Human Skin Mr. A. L. Corbett. Mr. A. C. Cole. Mr. F. Coles. Mr. W. H. Gilburt. Mr. J. W. Goodinge. Mr. A. H. Halley. Mr. Martin ell i. Mr. Moginie. Mr. J. H. Powell. Mr. H. J. Roper. Mr. C. Stewart. Attendance — Members, 79 ; Visitors, 10. October 12th, 1877. — Conversational Meeting. The following objects were exhibited : — Gizzard of Earwig Stained pinnule of Pteris aquilina. Wing of Diamond Beetle Ciranium ciUatum Forficula auricularia ... Section stem of Dahlia Diatoms from Whissonsett, Norfolk Diffiugia aculeata Basalt from Staffa and other localities Daphnia, &c. ... Lichmophora flabellata (alive) Selected Diatoms Arranged scales of Goat Moth ... A tter? dance — Members, 55 .. Mr. F. W. Andrew. .. Mr. T. H. Buff ham. ,. Mr. F. Coles. Mr. C. G. Dunning. .. Mr. F. Enock. ,. Mr. W. H. Gilburt. >. Mr. H. G. Glasspoole. . Mr. J. E. Ingpen. Mr. M. Hawkins Johnson. . Mr. A. Martinelli. . Mr. A. D. Michael. . Mr. H. J. Roper. . Mr. T. P. Watson. Visitors, 3. October 26th, 1877. — Ordinary Meeting. Henry Lee, Esq., F.L.S., &c, President, in the Chair. The minutes of the preceding meeting were read and confirmed. The following presents to the Club were announced : — "The Monthly Microscopical Journal" " Science Gossip " " The Popular Science Review " "The American Naturalist '' " Coal at Home and Abroad,'' by J. R. Leif- "> child, A.M. 5 Le Maout and De Caisne's " Descriptive ") and Analytical Botany " ... ... ) Huxley's "Anatomy of the Invertebrata" from the Publishers, in exchange. from the Author, by Purchase. 17 The Plates illustrating "Baker on the Microscope" Mr.Hawkins Johnson. Quaritch's " Catalogue of Books " ... ... from the Publisher. " Annals of Natural History " by purchase. "The American Journal of Microscopy" ... from the Editor. " The Medical Examiner." Weekly „ the Editor. " Proceedings of the Belgian Microscopical "i . , Societv Society > " J ' Photographs for the Album of Mr. S. A. Johnson, Mr. W. W. Reeves, Mr. Alpheus Smith, and Mr. Topping were also presented. The thanks of the Club were unanimously voted to the donors. The following gentlemen were balloted for and duly elected Members of the Club : — Col. H. Basevi, Mr. J. L. Luscombe, Mr. Bernard Smith, Mr. Saml. Smith, Mr. G. H. Wallis, Mr. W. Walters, and Capt. Weatherley. The President announced the forthcoming Soiree of the Croydon Micros- copical Club, and invited the assistance of such members of the Q. M. C. as might be able to be present on the occasion. Dr. James Edmunds then addressed the meeting " On a new Immersion Paraboloid Illuminator." He commenced by drawing the attention of the members to two objects — Amphipleura pellucida and Podura Scale — ex- hibited in the room, in order to illustrate the action of the Illuminator which he was about to describe. The first was an ordinary valve of A. pellucida, measuring about - 005 inch in length, and marked with transverse lines counting more than ninety thousand to the inch, the valve being dis- played upon a soft black background, and its lines with their interspaces showing as brilliant green and black bands. These lines and their inter- spaces — together measuring in round figures, nearly 200,000 to the inch- were distinctly separated, and made visible to the eye. The valve was seen through an immersion l-16th by Powell and Lealand and, so far as he (Dr. Edmunds) had learnt, A. pellucida had never been shown thus by any illu- minator that had previously been devised. The Podura was an ordinary scale of Lepidocyrtus curvicollis, lying in air, solidly upon the slide, with a thin cover close over its upper surface. The objective was a new-for- mula immersion -|th, by Powell and Lealand. It would be observed that a brilliant positive image of the podura scale — also upon a perfectly black background — was seen, and that the " markings " were shown demonstra- tively as minute featherlets, projecting up from the scale membrane. Podura Scale appeared to resemble a mat in structure, but its membranous basis was so hyaline that, under this light it blended with the slide, and trans- mitted light into the featherlets without itself becoming luminous. By shifting the lamp from side to side, or by altering the mirror to a small extent, these featherlets were seen to become shaded on either side, and on further alteration their images became so blended as to render optical defi- nition impracticable. In a particular light the tips only of the featherlets were illuminated, and these tips appeared as brilliant beads arranged on the scale in exact accordance with those ends of the markings which were towards the free end of the scale. This might easily be demonstrated by plotting out the "markings" under one light, their beaded tips — as seen C 18 by the other light — being afterwards counted off or plotted out for com- parison. The beads thus shown might also be seen less distinctly by the reflex illuminator and by the Wenham Paraboloid, and they were the heads of the "tadpoles" in what was at present regarded as the true image of Podnra. He would venture to designate this as the primary beading of the Podura Scale. Then at a certain point in a very careful illumination, and under amplification of the very finest character, there was a fine beaded structure to be seen in the scale membrane itself, analogous to the beading seen in other scales. This, he would venture to designate as the ultimate beading. It was, in fact, a true beading of the scale membrane itself, while the other, or pri- mary beading was, in reality, dae merely to a particular lighting up of the tips of the featherlets, their hyaline shafts and the scale membrane being left invisible, or almost entirely so. The true ultimate beading of the scale membrane was closer than the primary beading laterally by about two to one, while longitudinally it ran about five to one. In order to see the ultimate beading by the paraboloid, it was necessary to light the scale so as to make the featherlets invisible, and when these hyaline projections were not seen except as a thin haze over the image of the scale membrane, the true beading could be discerned. By transmitted light the images of the featherlets and of the scale membrane were necessarily blended together more or less completely, but with fine definition under an amplification of about 2,000 diameters, and with exact illumination they could be demon- stratively separated, if only the key given by means of this paraboloid illuminator were fully realised. The definition of Podura featherlets on black background was the best test he had yet seen for the most useful qualities of a high power objective. The ultimate beading could be ap- proached most easily through the study of the scale of the speckled Podura — the structure being more easily resolved in that scale. Eeverting to the illuminator, by means of which he had been enabled thus to unravel the structure of Podura scale, Dr. Edmunds proceeded to explain the construction and action of the Wenham-Shadbolt paraboloid, illustrating his remarks by drawings made upon the black-board, and showing wherein his own paraboloid differed from previous appliances of the same kind. Dr. Edmunds described his paraboloid as cut off at an exactly calculated dis- tance below its focus, this distance varying in the four lenses which consti- tute the set, and the plane top being made optically continuous, and as nearly as possible optically homogenous with the substance of the slide, by means of a cementing fluid of high refractive index, such as anhydrous glycerine, castor-oil, copaiba-balsam, oil of cloves, or a new fluid — " plumboxyde of glyceryl "—prepared by himself for the purpose. The latter fluid worked exactly like pure glycerine, and could be made of much higher refractive index. Chemically it might be described as glycerine with di-oxide of lead introduced into its molecular structure, in place of its equivalent of hydroxyl, but as he had not completed his work on this refracting medium, he would not now refer to it further. These paraboloid lenses acted upon the prin- ciple of total internal reflection, and each one was calculated for the thick- ness of the slide beneath which it was to be used, so as to converge upon 19 the object all the light entering the base of the paraboloid. No. 1 lens was calculated for nse with a slide of ordinary thickness, say a sixteenth of an inch. No. 2 lens was calculated for use with a slide not exceeding one- hundredth of an inch in thickness, and he had constructed " drum-head " mountings for objects between thin glass, which enabled an object to be viewed and lighted indifferently on both sides. Parallel light should be thrown into the base of the paraboloid, r and the most splendid effects were obtained by means of direct sunlight. The object might safely be illumi- nated up to apparent incandescence, without danger to the objectives. By a set of central stops, peripheral zones, and revolving shutters, the light might be narrowed horizontally, and thrown into the object at any angle and in any azimuth. One curious fact had come out, that the valves, now shown upon the table and so finely resolved under the light of this new paraboloid were not resolvable by Mr. Lealand with his former methods. This was owing to the fact that the valves being set upon the slide, there was a stratum of air between them and the cover which reduced the correc- tion of the lens so much that it lost that extension of angle by which it had power to resolve an acus valve when attached to the under surface of the cover — the space between the object and the lens being then wholly occupied by glass-cover plus water, instead of as at present partly by air. This fact raised the question how much the value of " angle of aperture," depended simply upon the reception of additional light from the object, how much upon angle qua angle. But this he would not now attempt to discuss. It was, however, important to note that the pure brilliant positive image of an object, as given by this paraboloid, was resolvable by a lens with smaller angle of aperture than was another image, and, if we could by new means of illumination increase the resolving power of low angled lenses, a vast gain would be made. The defining and resolving power of an astrono- mical telescope depend directly upon the area of objective — other things being equal. Here the difference consists purely in bringing into the image a larger number of pencils of light from the planets or other objects, the question of angle qua angle not coming into account. The telescopic image is a positive one, and the blacker the field the finer the impression made upon the retina. In the microscope, the negative image only being seen by transmitted light, the most luminous area before the eye was necessarily the blank field, while the object was recognized only by its power of obstructing light, and was comparatively weak in its impression upon the retina. With this positive image, on the other hand, there was a soft black background, and the brilliant image of Podura or Acus as thus shown, obviously had immense advantages in regard to its power to impress itself upon the retina. With bacterial fluids the effect was equally remarkable. Saliva, blood, &c, viewed by a good dry quarter of about 95°, were seen almost as new ob- jects, when lighted up by this paraboloid. Mr. Ingpen said that the Club was highly indebted to Dr. Edmunds for bringing the matter before it, and the subject was certainly one of very great interest. It was also a curious instance of the way in which an in- vention might be made before the time came for its due appreciation, and 20 then be re-invented quite independently by others a long while afterwards. It would perhaps be remembered that Mr. Wenham introduced the immer- sion paraboloid in 1856, and that in 1871 Mr. B. D. Jackson read a paper before the Club on the same subject, the re-invention in that case being by Dr. Barker, but not only was its re-invention by Dr. Edmunds perfectly genuine, but the instrument stands now upon what may be called a different platform, because many improvements have been made in objectives and methods of research. The instrument was now introduced to a more appre- ciative audience than formerly, and at a time when the subject of the ex- amination of minute structures rested upon a widely different footing from that which existed some years ago.* Dr. Matthews said that, about two years ago he had come to the conclu- sion that the " markings " upon Podura scale were really club-shaped pro- jections from the surface of the scale, but he had never been able to de- monstrate the fact as Dr. Edmunds had done to-night. He was enabled to say this quite two years ago, though he knew that the idea was then thought to be very heretical. He did not think that they could possibly get both positive and negative images of an object by sub-stage illumination. In the case of translucent objects, they might get them illuminated all round by horizontal rays, but even then they would get a negative image, and they could only get a positive image by light thrown down from above the level of the surface of the object; all forms of illumination that did not exceed the angle of 90 e from beneath must necessarily give negative images. Then it must not be overlooked that, in so examining scales, they were look- ing at objects consisting of two layers, with light entering from beneath. They therefore got confusion between the markings on the upper and lower surfaces which was much apt to mislead. As long as objects were illumi- nated from beneath, he could not enforce it too strongly that they never could get a positive image. Dr. Edmunds asked Dr. Matthews to examine the images again. The President said there was a class of evidence which it would be very desirable to get if possible, seeing that Dr. Edmunds claimed certain advan- tages and power of definition — perhaps Mr. Powell or some other gentle- man with practical knowledge would give them their opinion from experi- ence. Mr. Powell said he had not tested it upon any other objects than Amphi- pleura pellucida, but he found that it showed the markings in a way which, no other method would do. Dr. Matthews (after examination) said he saw the objects exactly as Dr. Edmunds had described them, but it was quite clear that the illuminating rays approached them from beneath, and that in order to get a positive image the light must fall upon the object from above. Dr. Edmunds thought there were reasons why he might still ask Dr. * Note. — Upon the question of priority, Dr. Edmunds writes :— " As between Mr. Wenham and myself, I need only to observe that the paraboloid described by Mr. Weuham was not like miue, either in its formula or in its effects, and that the methods of working and applying the two instruments as accessories to the microscope dj not in the least resemble each other."— Ed. J. Q. M. C. 21 Matthews to re-consider his judgment. In the case of light converging at an angle of 85°, if they took the thickness of the covering glass and of the stratum of air between, and also the thickness of the film of water into consideration, they would see that light passing at an angle of 85° could not enter the objective at all, but could only be seen as light received by the object and again thrown out by it as its own radiant. They saw an object negatively by virtue of its power of obstructing light, whereas, if they could make it receive light to such a degree as to become its own radiant while no light entered the objective except that given out by the object, he apprehended that it must be seen as a positive image. Here it was seen upon a perfectly black background, the Podura scale appearing as if in- candescent. Dr. Matthews said that the principle enunciated by Dr. Edmunds was perfectly correct, but yet he could not see that any object illuminated only from below could afford any other than a negative image when looked at from above — unless light were reflected back upon it from the under surface of the cover. Dr. Edmunds feared he had not clearly explained ; no light could come up through the surface of this slide, except into the substance of the object, otherwise they would of course cease to get the black background. The President said that the discussion as to positive images opened up a series of complicated questions, which it was clear they could not go into that evening. A vote of thanks to Dr. Edmunds for his communication was then unani- mously carried, and the proceedings terminated with the usual conversazione, at which the following objects were exhibited : — Section of China rose ... ... ... ... by Mr. F. W. Andrew. Spicules of Holothuria ... ... ... ... „ Mr. T. H. Buff ham. Anchors of Synapta ... ... ... ... „ Mr. F. Coles. Scalariform tissue of Fern ... ... ... „ Mr. A. L. Corbett. Podura scale, Lepidocyrtus curvicollis (shown I y. -p, , -, by Dr. Edmunds' immersion paraboloid) J Strophosonius obesus ... ... ... ... „ Mr. Enock. Scylla, from wet moss ... ... ... ... „ Mr. H. E. Freeman. Sieve tubes from Dahlia „ Mr. W. H. Gilburt. Fin of young Carp „ Mr. Halley. Nasal Polypus „ Mr. J. J. Hunter. Grammatophora marina ... ... „ Mr. Michael. Section of Human Tongue ... ... ... „ Mr. Moginie. Amphipleura pellucida (by Dr. Edmunds' > i\r -d m r ,, Air. Jrowell. immersion Paraboloid) ... ... * Arachnoidiscus ornata ... ... ,, Mr. B. W. Priest. Mignonette „ Mr. F. Reeve. Polycistinoa „ Mr. Swift. Attendance — Members, 86 j Visitors,, 14. 22 November 9th, 1877. — Conversational Meeting. showing") The following objects were exhibited : — Asparagine Uraster glacialis Wing of Rrtinia resmella Selected Diatoms Section of tuber of Dahlia, crystals of Inuline ... Trichina spiralis Insect mountings from Ceylon ... Large intestine of Guinea-pig, injected and stained Chirping file of Cricket ... Tran verse section, head of Wasp... Section of human kidney, injected 1 Mr. F. W. Andrew. Mr. T. H. Buffham. Mr. F. Enock. Rev. H. J. Fase. Mr. W. H. Gilburt. Mr. J. J. Hunter. Mr. Ingpen. Mr W. W. Jones. Mr. W. Moginie. Mr. E. T. Newton. Mr. J. W. Reid. Attendance — Members, 43 ; Visitors, 6. November 23rd, 1877. — Ordinary Meeting. Henry Lee, Esq., F.L.S.. &c, President, in the Chair. The minutes of the preceding meeting were read and confirmed. The following donations to the Club were announced : — From the Publishers. „ „ Society. By purchase. ,, the Society. V » " Science Gossip " " Proceedings of the Royal Society " "Annals of Natural History " " Rules of the Royal Society of New South) Wales" ... ... ... ) " The American Journal of Microscopy " ... " Proceedings of the Belgian Microscopical") Society' ... ... ... ) "The Medical Examiner " (weekly) "The Analyst"... " Pamphlets by Dr. Wallich on the North") Atlantio sea bed, - ' &c. ... ... ) A l-5th Objective for use with the Club) microscope ... ... ... j 15 Slides of Anatomical preparations 12 Slides of Vegetable tissues ... 24 Slides of Physiological Preparations 1 Slide of Licmophora The thanks of the Club were unanimously voted to the donors. The following gentlemen were balloted for and duly elected members of the Club :— Mr. W. S. Dallas, Mr. W. Goodwin, Mr T. S. Morten, Dr. A. H. Newth, Mr. Thomas Simpson, and Mr. George S. Williams. The President said that from time to time the question had been brought ,, Editor, the Society. the Editor. the Author. Mr Wray. Mr. A. C. Cole. Mr. W. H. Gilburt. Mr. J. Hunter. Mr. A. D. Michael. 23 before the Committee as to the further utilisation of the gossip nights, and suggestions had been made as to the conducting of some kind of class in- struction on those occasions. The committee had always been very careful not to interfere in any way with the informality and freedom of those meet- ings, and the subject had, therefore, been rather difficult to deal with; but a sub-committee had been appointed to consider the whole question, under in- structions that if the idea could be carried out without interference with the ordinary procedure, it would meet with approval. This sub-committee had unanimously recommended that the experiment should be tried, and the committee had agreed to do so. At the next gossip night, therefore, one of the " Bays" in the room would be occupied by a member of the committee, who would give a brief description of the theory and construction of the microscope, to all who chose to attend to listen. The committee would have this matter under strict supervision, in order that the freedom of the members on those occasions should not be in any way interfered with. Mr. Ingpen said he had a short communication to make, arising out of Dr. Edmunds' paper, read at their last meeting, with reference to his method of mounting test objects. This method was so simple and so good that it was worth drawing attention to it. Dr. Edmunds took a thin slip of cedar wood, 3in. long and If wide, and cut a round hole through the middle li in. in diameter. Over this hole he pasted a piece of the thinnest bank post paper, having a fin. hole punched in it. The object was then placed between two pieces of thin glass, cemented together, and these were cemented to the paper. The object was thus mounted between pieces of glass, so thin, that it could be reversed and viewed from either side equally well, and the under side admitted of the use of the immersion paraboloid, whilst the paper being elastic, formed as complete a protection to the objective as even a " Stephenson's safety stage." Mr S. J. Mclntire called the attention of the meeting to some larvae of the cat flea, which he had brought for exhibition that evening. Having shaken out upon a newspaper the basket which his cat and her family had occupied, he found, amongst other things, an immense number of the larvaa of the flea, as well as numerous eggs. The eggs were small, pearly objects, and very pretty under the microscope ; and the larvae were white at first, with a few hairs on them, and divided into 13 segments. The food of the larvae consisted of the excrement of the flea ; in due course the larvae entered the crysalis state, and finally changed into the perfect insect. There was a paper upon the subject in " Science Gossip'' for 1865,* which might, perhaps, be forgotten by those present 5 he, therefore, thought it might be of interest to bring the subject again before them. The best objective for the examination of the larvae was a 3in. Mr. J. G. Waller read a paper " On a new British Sponge of the Genus Microciona, for which he proposed the name of M. bihamigera. The subjecb was illustrated by diagrams, and by a specimen of the new species. Mr Chas. Stewart, at the request of the President, gave an interesting des- cription of the characteristics of sponges generally, in the course of which * See " Science Gossip," Vol. i., p. 278, aud Vol. iii.,p. 47. 24 he said that they were very widely diffused, and were found in the sea at all depths, from between the tide marks to several miles. As a rule, they were very brilliantly coloured objects, and all the species were fixed in various ways, according to their natural habit, or to the position in which they were found. Their varied modes of attachment were then described, and also the beautiful species which anchored themselves to the mud and ooze. Ryalo- nema, Ewplectella, &c, were figured upon the black-board. The general anatomy of the spouge family was then dealt with, and they were shown to be covered by a dermal membrane, perforated with small holes, the whole mass being traversed by a number of canals, which opened into the sub- dermal chambers on the one hand, and the oscula on the other. The pro- cess by which the currents of water through these channels were set up and maintained was next explained, attention being called to the contractile power possessed by the fleshy portions of the mass. The infinite variety and specific characters of the spicules were next adverted to, and as regarded their mode of reproduction, it was pointed out that they came much nearer to the zoophytes than to the Infusoria. Mr J. G. Waller expressed the pleasure which he felt at hearing the sub- ject of the Spo/igiada brought before the Club in so interesting and able a manner. With regard to the contractile power of sponges, he would just mention that in detaching the sponge from the rock it contracted visibly, and discharged quite a large quantity of water. As to gemmules, he was not quite sure if they were right in calling so many things "gemmules, ' and thought it very possible that they might have to modify some of their opinions upon this subject. The President said that when he looked at the drawings of the species des- cribed by Mr. Waller, it struck him that he was in some way familiar with it, but whether it was one which had been shown to him by his late friend, Dr. Bowerbank, under his microscope, or whether it was figured amongst the plates which were prepared as illustrations for the 4th Volume of '' The British Spongidaa," he could not say from memory. It would, however, gratify them very much if it should turn out that a new species had been dis- covered by a member of the Club. Since Dr. Bowerbank's time some modi- fications had already been made, and it was curious to remember that with regard to Hyalonema they could never get him to acknowledge the fact that it grew the right way upwards, and he always would call it the " basal sponge," but they knew better now. The study of sponges offered a very wide field for research, and though some observers abroad were doing a little, they might say that there was no one in England who was making a study of them, now that Dr. Bowerbank was gone ; he would, therefore, venture to urge it upon the consideration of the members how vast was the field before them, and if the paper of that evening was the means of inducing others to take up the study, he should be heartily glad. The thanks of the meeting were then unanimously voted to Mr. Waller and Mr. Stewart for their communications. Mr. Ingpen called the special attention of the members to the slides which had been presented to the Club by Mr. Cole, Mr. Hunter, and 25 Mr. Gilburt as being beautiful and valuable additions to the cabinet. With reference to the " elementary gossips " proposed, he wished it to be under- stood that they were at present to be considered as quite an experiment, rendered desirable by the fact that some of the members had expressed to him a wish for microscopical instruction of an elementary character. He had undertaken the first of the series, and hoped that whatever the result might be, the members would give him credit for the motives which actuated him in suggesting such an innovation. The proceedings then terminated with a conversazione, at which the following objects were exhibited : — Transverse Section of Tail of Puppy Stained Pinnule of" Polystichum angulare" Spicules of Sponge Lemon Parasite Ciniflo similis Section of stem of HeManthus maa phyllum "I Mr. W. J. Brown. Mr. Buff ham. Mr. A. C. Cole. Mr. A. C. Coxhead. Mr. F. Enock. Mr. W. H. Gilburt. Skin from a Cape Bulb ... Jaw of Foetus Larvae of Cat Flea Porous Vessels in Beet-root, &c. ... Leg of Fly, with parasite Saw Fly — Tenthredo variabilis ... ... ,, Attendance — Members, 80 ; Visitors, 1 5. Mr. Glasspoole. Mr. J. J. Hunter. Mr. S. J. Mclntire. Mr. Martinelli. Q.M.C. Microscope. " December 14th, 1877. — Conversational Meeting. } The following objects were exhibited : — Tobacco-leaf, showing the hairs and spiral") tissue ... ... ... j Stained Blade of Maize, showing stomata Head of Pulex adherens, dissected by Mr. Tatem Eggs of Parasite of Pheasant ... Pediculus MeUtte (Parasite of Wild Bee) ... Melicerta ring ens, surrounded with Vorticella Transverse section of Taxus baccata, double} stained ... ... ... j Foraminifera ... Wing of House Cricket (polarized) Injected sections of Kitten Injected sections of Guinea-pig ... Lenticular (?) images in areolar structure") of Triceratium septangulatum ... ) Obelia geniculata, with tentacles extended... Colorado Beetle Mr. F. W. Andrew. Mr. T. H. Buffham. Mr. T. Curties. Mr. C. G. Dunning. Mr. F. Enock. Bev. H. J. Fase. Mr. W. H. Gilburt. Mr. H. F. Hailes. Mr. A. H. Halley. Mr. J. J. Hunter. Mr. W. W. Jones. Dr. Matthews. Mr. A. D. Michael. Mr. W. Moginie. 26 Euplectella, showing floral spicules in situ... Mr. B. W. Priest. Diatoms from Penang ... ... ... Mr. F. Roper. Podura scale with l-10th immersion obiec-) ,_ T _ ... J [ Mr. J. Swift. jective ... ... ... J Mr. Ingpen gave an elementary description of the theory and construc- tion of the microscope. Attendance — Members, 66 ; Visitors, 10. December 28th, 1877. — Ordinary Meeting. Dr. J. Matthews, F.E.M.S., Vice-President, in the Chair. The minutes of the preceding meeting were read and confirmed. The following gentlemen were balloted for and duly elected members of the Club : — Mr. J. A. Batchelor, Dr Thos. Partridge, Mr. Chas. Sands, and Mr. Thos. Wm. Watson. Seven gentlemen were proposed for membership. The following donations to the Club were announced : — " The Monthly Microscopical Journal " — " "I from the Publishers. November and December " Science Gossip" ... ... ... „ „ " Proceedings of the Natural History^) _. . . q • 4- J m * i » Society. Society or Glasgow ' ... J "The American Journal of Microscopy"... in Exchange. " Annals of Natural History " ... ... by purchase. "Grevillea" ... " The Medical Examiner " (weekly) . . . from the Publisher. " Eeports of the Smithsonian Institution"... ,, Institution. "The Analyst" ... ... ... „ Publishers. " Proceedings of the Belgian Micro scopi-"") . cal Society" ... ... j " The American Naturalist " ... ... in exchange. " Proceedings of the Geologists' Associa-) „ ,. . ... } from the Association, tion" ... ... ... j " Proceedings of the Watford Natural^ „ . History Society " ... ... ) " Catalogue of the Diatomacese,'' by Mr.") . ,, F. Habirshaw, of New York ... j Six Slides ... ... ... ... from Mr. T. H. Buff ham. Mr. T. Curties. Mr. A. D. Michael. Mr. Moginie. Mr. Tatem. Six ditto Six ditto One ditto Six ditto The thanks of the meeting were unanimously voted to the donors. Mr A. Cottam read a paper "On the New Autographic Process," in which he fully described the modus operandi, and strongly recommended the adoption of the method as being much superior to lithography— as 27 ordinarily understood — for the reproduction of microscopical drawings. Specimens of the transfer paper, and numerous prints executed by the process, were exhibited in illustration of the subject, and were subse- quently distributed amongst the members. Mr. J. G. Waller had seen the working of the process, as a friend of his was in the habit of making all his drawings by it, and he could say from knowledge that it would be found to answer the purpose in every respect. The Chairman said he could fully endorse the opinion of the reader of the paper as to the great desirability of an observer illustrating his own observations. Sir John Herschel used to say that an anatomical observa- tion required not only a telescope and an object, but also an eye ; and the paper they had jiist heard seemed to show that another thing was also necessary, namely, a hand. Mr. Marcus M. Hartog read a paper " On the Investigation of Floral Development," in the course of which he described the best method of dis- secting and examining the subjects under observation, and gave many valuable hints as to the most useful appliances for the purpose. The Chairman, in proposing a vote of thanks to Mr. Hartog, expressed his sense of the value of the paper, which he thought was one of the kind they so urgently needed, as being a description of new and useful modes of investigation by simple means. He heartily commended the suggestions which Mr. Hartog had made to the attention of the members. Mr. Gilburt said there was just one other "little dodge" which would be found extremely useful, because it enabled fresh sections to be mounted at once. Fresh sections of the " growing point " should be made and put into alcohol for about ten minutes, after which they could be put into oil of cloves and then into balsam. By this means the protoplasm was shrunk a little from the cell wall — which was an advantage — and they could take sections from the growing point to the extreme end, and preserve them directly, and much better than by using glycerine ; the whole process could be gone through in half an hour, and they got the sections well preserved in what was practically their natural condition. Balsam in benzole should, however, be used, as it worked better and was more suited to the purpose. Mr. Ingpen enquired if the lenses of the simple microscope recommended by Mr. Hartog were single lenses or achromatic combinations ? Mr. Hartog said they were not achromatic, but the form was a doublet which Chevalier had long adopted, consisting of two plano-convex lenses, with a diaphragm between ; the lenses were of different sizes, the small one being at the top, and both having their plane sides towards the object. Mr. Ingpen said this arrangement was the converse of the well-known " Wollaston doublet," which had the larger lens above the smaller one^ This combination was new to him, and he was much struck with the size and flatness of the field it gave. The stand was certainly very well adapted for the purpose of dissecting. The Chairman thought the stand was quite a model of firmness. He asked if Mr. Hartog found much difficulty in holding the object during dissection ? 28 Mr. Hartog said that the manipulation was extremely difficult, and only to be attained by practice ; he only held the object with one needle whilst he worked with the other. Mr. Ingpen said he could corroborate what had been said as to the value of the lancet-shaped needles for purposes of dissection. They were diffi- cult to get here of exactly the shape, and he generally had to get them ground from " eye-knives." Mr. Hartog said he had been informed that it was possible to examine even a dried specimen by soaking it in water, and afterwards plunging it into alcohol. The Chairman thought the question of holding objects during manipula- tion was one of very great importance. He had seen sections of fungi growing on a leaf, and could not imagine how such beautiful sections were produced — showing perfectly the shape of the cups. He should be glad if any one could tell him how they were made. Mr. T. C. White said he had some little experience in insect dissection, and there were a great many small specimens which were not capable of being pinned down, and for holding which he had made a composition of Canada balsam and bee's wax, which held them perfectly, and did not dissolve under water. It seemed to him that perhaps this might be useful for the purpose of holding the vegetable specimens, and thus enabling the operator to use both hands freely. The Chairman thought that a vegetable tissue would not be so firmly held in such a medium as was necessary. The Chairman announced that at their next Gossip night Mr. T. C. White had undertaken to give a viva voce account of the mysteries of balsam mounting. The proceedings then terminated with a conversazione, at which the following objects were exhibited: — Mole Flea (eyeless) ... ... ... Mr. F. W. Andrew. Stained Filmy Fern (Hymenovhyllum Tun-~) __ _ TT _ W1 J v y r * \ Mr. T. H. Buffham. bridgense) ... ... ... ) Scaled Spider (from Ceylon) ... ... Mr. Curties. Rabbit Flea ... ... ... ... Mr. F. Enock. Mandibles of Scorpion ... ... ... Mr. H. R. Gregory. Kidney of Pig ... ... ... Mr. J. J. Hunter. Melicerta, Stephanoceros, &c. (fromHampO i Mr. Le Pelley. StGcLCi J ••• ••* ••• Alpine Beetles (Batrisus formicarius) ... Mr. R. T. Lewis. Colorado Beetle ... ... ... Mr. Moginie. Eydoida sertularia ... ... ... Mr. T. S. Morten. Aulacodiscus ancenus (from Moron) ... Mr. T. H. Powell. Attendance — Members, 39; Visitors, 7. 29 On Glyciphagus palmifer. By A. D. Michael, F.R.M.S. (Bead 25th January, 1878.) Plate III. During the Christmas time which has just passed I went for a visit of a few days to some friends living in a small agricultural village in Warwickshire, a few miles from Tamworth, and, the weather being too bad to venture out, it struck me that I might as well see what objects of microscopic interest I could find in the house ; with this view I descended into the beer cellar with a plate of glass and a camel's-hair brush, and gently brushed a small part of the wall on to the glass ; the result, on examining the sweepings, was that I found a good number of living specimens of Glyciphagus palmifer, and as this most beautiful and extraor- dinary mite has not hitherto been found in this country, as far as I can ascertain, I have thought that it might be of sufficient interest to exhibit to you to-night ; and I have been asked to describe it. Before doing so, however, I wish to say that the sub- ject has been most admirably and exhaustively treated by MM. Robin and Fumose in " Robin's Journal pour l'Anatomie et Physio- logic " for 1868, and those gentlemen have left little that is new for any one else to add ; the work, however, is difficult of access in this country. There is also a short notice of the species in Mr. Andrew Murray's late work on the Aptera, with a drawing very well copied from Robin and Fumose's figure by Mr. Whymper ; which drawing, however, being somewhat highly shaded, scarcely gives as correct an idea of this white and transparent creature as the original, more diagramatic, figure. Mr. Murray anticipates in his article that as G. palmifer is found both in France and Germany, it may possibly also be found in the southern parts of this country if properly sought for. I do not, however, myself consider that the mite is finally established as indi- genous here by my capture — in the first place because so ?ery minute 30 A. D. MICHAEL ON GLYCIl'HAGUS PALMIFER. a creature as this, particularly when inhabiting cellars and places whence goods are exported to foreign countries, is very easily carried with those goods, and very easily spread afterwards, when those, or other goods lying near them, are sent from one place to another ; and this reason appears to me to render it always very difficult to say whether such creatures are indigenous or introduced ; and in the next place, because, at the suggestion of Mr. Murray — whose loss we all of us, I am sure, deplore — I caused enquiries to be made, and ascertained that some three or four years ago my friends imported a cask of claret from Bordeaux, which was stored for a time in part of the cellars not very far from where I found my specimens : there are not any to be found now, either in the place where the cask was kept or on the cask itself, but they might have migrated to a more congenial place. After a day or two a thaw came on; and the cellar wall streamed with damp, I then failed to find any more ; but I brought up some scrapings from the wall from which I have since bred several. The genus Glyciphagus belongs to the true Acaridaa : it is characterised by a pointed rostrum with chelate (nipper-like) man- dibles ; a dorsal depression instead of a distinct transverse line between thorax and abdomen ; a five-jointed leg, with the tarsus terminated by a small sucker and very small single claw ; and par- ticularly by three peculiarities, viz. : — lstly, the skin of the back being plicated to such an extent as to present a velvety appear- ance ; 2ndly, the body in the females being terminated by a short projection, or anal button, as Murray calls it ; and, ordly, the hairs or some of them being either plumose or developed into the remark- able leaf-like expansions which I am about to describe. MM. Robin and Fumose divide the genus into two sections, th<> second section containing the present species, and being distin- guished by the body being shorter, smaller, and less indented, the skin more wrinkled and velvety, and the hairs either very plumose, as in G. plumiger, or else developed in the remarkable manner which is observed in this species only ; but before describing these I will pause for an instant to point out that this may be considered the culminating point of that series of hair developments which the mites present. In the first place we have the simple hair, as in Tyro- glyphus, then in such a species as Trombidium curtipes we have the knobbed hair so well known in plants. Then, in Pteroptus and Otonysus, we have the imbricated hair like that of the bats, a fact which Mr. Murray justly remarks is very singular, since both of A. D. MICHAEL ON GLYCIPHAGUS PALMIFER. 31 tliese genera are parasitic on bats ; but the parasites of bats are not the only mites that have the imbricated hair, as I find it even more stronsrly marked on the hairs on the legs of some of the rarer Cheyleti; then in Glyciphagus we have the plumose hair, either slightly so, as in G. cursor or G. spinipes, or almost forming a plume, as in G. plumiger ; and lastly we have the present species, which seems to show the transition of hairs into scales. In G. palmifer the hairs along the edge of the body are developed into what Murray calls " pennate, transparent, spatulate plumes," which, however, I prefer to call leaf-like expansions. These stand out from the edge of the body and curve slightly downwards ; there is a thickened mid-rib, or, so to speak, a quill, from which lateral nervures run to the thickened margin of the leaf. These nervures sometimes go straight from the mid-rib to the margin, and sometimes divide into two or three before reaching it. The edge of the leaf is thickened, forming a rim all round, from the exterior of which spring a number of short, strong spines, not continuous with the nervures, but more numerous, and set at a different angle. There is also a double row of similar spines down the mid-rib diverging. The mid-rib is joined to the nervures and rim by a transparent membrane. Each hair is set in the usual way into a little projection or papilla of the body, the mid-rib only running in like a quill ; this I have seen best by polarised light, with a blue selenite, when the mid-rib — even that part within the body — assumes a brilliant metallic green, and is very conspicuous. The leaf-like hairs are very different in the male and female, those of the female being shorter and broader, and more leaf-like, than those of the male ; but there are two plumes not far from the anus in the female resembling those of the male. A drawing of one of the leaf- like hairs of the female, highly magnified, is given (fig. 3). At each side of the back, a short way from the posterior margin, is a single leaf-like hair (in the female) which, in the male, is replaced by a very long plumose bristle, standing out transversely, and which Robin and Fumose draw as turning sharply round at a right angle about one-third of the distance from the tip, and Murray copies it thus ; in spite of the ability of Mr. Murray, from whom one differs with great hesitation, I have not liked to draw it so, as it has not been so in any of the numerous specimens which I have seen alive ; and it appears to me that Robin and Fumose did not intend it as a fact, the hair being bent conspicuously in order to get it into the plate, fur which it would otherwise be too long. This 32 A. D. MICHAEL ON GLYCIPHAGUS TALMIFER. is not unusual with French draughtsmen. These hairs, both in the male and female, appear to form good sexual distinctions, as they are absent in the nymphs, which are devoid of sexual organs, but in other respects resemble the perfect creatures, both male and female. The colour is clear, grayish white, the body is flattened and attenuated in front, but more so in the male than in the female, giving the former a more pear-shaped and the latter a squarer appearance. The transverse depression of the skin on the back is marked by a line of strong warts. The males are smaller than the females. Robin and Fumose give the average sizes as follows : — Males, *20 to -25 mm. long ; •14 to '16 mm. broad. Female, "30 to "35 mm. long ; '18 to '22 mm. broad. The legs are larger in the male ; the tarsi alike in both sexes — nearly as long as the width of the body ; the sucker is larger than in most species of the genus, the claw monodactyl, and extremely small. The male organ is placed between the insertions of the third pair of legs, and does not reach the insertion of the second pair ; the vulva is placed between the insertions of the third and fourth pairs of legs, and is considerably enlarged posteriorly. During copula- tion the two remain in contact by the ends of the abdomen, and the female continues to walk dragging the male. The anal appendage (to the females only) is a short truncated cone. The palpi are cylindrical and three -jointed. The larva is hexapod, about half the size of the imago, and devoid of the anal appendage and sexual hairs on the back. The Nymph is octopod, larger than the larva, but is devoid of sexual organs, anal appendage, and sexual hairs on the back. The egg is a long oval, depressed on one side. The pace of the creature is slow, but the males walk faster than the females. The species frequents the dust and walls of damp cellars. DESCRIPTION OF PLATE III. Fig. 1. — Male. Upper side, X 200, a, Sexual hairs. Fig. 2. — Female. Under side, X 200. a, Anal projection; b, Vulva. Fig. 3. — Leaf -like Lair, X about 1,000. Fig. 4. — Mandible, X about 1,000. Fig. 5. — Tarsus and Claw, X about 1,000. 33 A Few Remarks on Insect Dissection. By T. Charters White, M.R.C.S., F.R.M.S., &c. (Bead January 25, 1878.J Perhaps no field of microscopical research teems with richer veins of interest and instruction than that upon which I have ventured to intrude this evening, but feeling so deeply interested in it myself I may be pardoned if, in the absence of others better qualified, I en- deavour to throw out a few suggestions that will be of assistance to those amongst us, who, taking up the scattered clews of my short paper, may work them into a fabric of surpassing pleasure. The lengthening days of early spring already invite our attention to the resurrection of animal and vegetable life, and, like good generals, preparing for a campaign, we should begin to lay our plans for future work during the coming year. With the advent of our summer excursions many opportunities will be afforded us for leaving the busy throng, and exchanging its bustle for a few short contacts with nature in her loveliest aspects ; and while many of our members will find a revival of old delights in the capture of Conochilus and Volvox, there may be others who, like myself, see in their revolutions, beautiful as they are, only the same monotonous rolling as we have ever witnessed, and would rather behold something of that wondrous evolution manifested in the development of the various forms of insect life, so abundant in the early months of the year ; and which may be compared to simple ex- periments in biological science, ready-made to the hands of the diligent students who will take the trouble to look for them. Of all anatomical studies, that which treats of the comparison of a particular organ in one animal, with its homologue in another, yields the most untiring pleasure to those engaged in them. The study of comparative anatomy is inexhaustible in its interest, and many amongst us would take it up but for a mistaken notion which pre- vails, and leads many to suppose that all studies having anatomy for their basis should, by reason of their nature, be relegated to the 34 T. C. WHITE ON INSECT DISSECTION. region of the medical theatre and the dissecting-room, that none but "doctors," especially educated for such researches, are capable of mastering the difficulties of their details ; but that feeling is a mis- take, and the sooner it is dissipated the sooner will the clear light and joy of a new field of investigation be opened up for your delec- tation. With these few words of encouragement, I will proceed to say something relative to the practical carrying out of the subject under consideration. Three things will be found necessary, viz., magnifying power, good light, and instruments, and we will treat of these in this order : — ■ All who have seen the dissections made by our friend and fellow member, Mr. W. T. Loy, must have admired the skill and neatness with which they were done, and could only regret that he had not in many more instances carried them on to the isolation of the separate organs of each insect, for no member seems to possess greater opera- tive delicacy than he. By his kindness I had an opportunity of in- specting a very ingenious method of adapting his magnifying power to his work, which I should like to describe to you, although I have not his permission for so doing : it struck me by its simplicity, as well as by its efficacy, and therefore I trust I may be allowed to mention it without incurring the character of revealing any private affair. It consists of a heavy metal foot, into which an upright iron rod is fixed— round this rod is coiled one end of a stout wire, the other end of the wire being bent into a ring to hold a watchmaker's eye-glass; this arrangement, by pressing the head down, focussesthe lens upon the work while both hands are at liberty, and when I tell you that all these beautiful dissections of his were accomplished by such a contrivance, it will be sufficiently recommended to your use, even if we leave out of consideration its comparative cheapness, com- pared with other optical arrangements. The dissecting microscope I made for my own use some years ago is more complete than that I have just described, and would, if made by an instrument maker, be more expensive than that of Mr. Loy. It consists of a rod sliding within a tube, and made to stop at any ele- vation by a fiat spring attached to it and pressing against the inside of the tube. The tube screws into a hole in the dissecting table, and the upper end of the rod is made small enough to be inserted into the hole in the handle of the ordinary three-glass pocket lens ; by this means each of the three lenses may be used as occasion T. C. WHITE ON INSECT DISSECTION. 35 requires and brought to bear on the subject. The lower power microscopical objectives, such as the 1 inch, 1| inch, and 2 inch, may also be used, being supported in such an arrangement as that first described, but far better results will be attained by the use of an erecting glass in the tube of your microscope, because that affords a ready method of varying your magnifying power and adapting it to the dimensions of the work under dissection, and rendering what would be otherwise very difficult a simple matter of steadiness of the hand. Our next consideration must be in the direction of a good light, and this, with some dissectors, is so important that it occupies a priority over magnifying powers ; but, however much we may differ from them in this point, there cannot be a doubt about this opera- ting as a most important factor if we would get good results ; and although a successful dissection may be made with a full light con- densed on your work, yet better will be obtained by your light being supplemented by the magnifying power. The plan 1 have adopted for this is inexpensive and simple — a Florence oil flask is well cleansed and filled with water, then securely corked and waxed to prevent leakage. It is then supported longitudinally by a tube which grasps its neck, the tube itself being supported on an arm held on a heavy foot ; this gives the power of adjusting the focus of its rays upon your dissection to any extent you may deem desirable, while should a fracture of your flask occur it is easily and cheaply replaced. The morning light is better than any other, the horizontal rays falling more agreeably on your work than the vertical rays from a lamp at night, and in the morning the hand is steadier for the work. An advantage is gained sometimes in dissecting by transmitted light, especially if you can impart a blue tone to it ; at other times greater advantage is attained by dissecting by reflected light, and on a black ground. As an aid, I would also recommend that your subject should be stained by carmine or logwood before dissecting. The instruments necessary for insect dissection are not expensive, and may nearly all be prepared at home ; but one essentially useful is a pair of small spring scissors. These cannot be dispensed with, nor can a firm but fine pair of forceps, for before you can reach the internal organs of an insect it is necessary to remove the external chitinous integument, and in some cases this is so hard that in the case of the stag beetle a pair of wire nippers will not be too strong for this purpose. The cutting instruments, the scalpels, in fact, 36 T. C. WHITE ON INSECT DISSECTION. may be formed out of needles set firmly in wooden handles. They may be of different widths and of various curves — such a needle ground flat and sharpened makes an excellent knife, while some of the needles may be blunt and slightly bent for the purpose of holding the different J3arts down while they are cut, or of separating the organs from the entangling mass of trachea}, with which they are bound to the adjacent structures. Another useful auxiliary will be found in the fluid under which you must always carry out your dissection, by increasing the density with glycerine, and varying it according to circumstances, it may be made to support and hold out of the way delicate structures that would be liable to injury or impede the progress of dissection during the operation. The other implements necessary are a small square of entomo- logical cork, loaded by insertion in a plate of sheet lead, to which your subject may be fixed. A glass trough, about 1 inch in depth, or even less for some cases, is better than any other I have tried. Noav I do not, in this short paper, pretend to give you anything more than the modus operandi I have found useful to myself. I know there are others here who may have further information to im- part relative to their procedure, and to those these few remarks may serve as the text for the subsequent discussion. In preparing an insect for dissection, if you intend to examine merely the internal organs, it is better to remove all the external organs as the legs, antennae, &c, of course previously killing the in- sect with chloroform. Then the plan usually recommended is to pin the subject on the loaded cork, and place it in the trough under water. Now this plan is very well in some cases, but I prefer another, which I can recommend as being far more efficacious, and that is while your insect is dry drop upon the part you intend to fix it by, some melted wax and Canada balsam, the same composition that I have before recommended to be used as a cement for cells in dry mounting, only in this case you have to add a little more Canada balsam. You may then drop some more on your loaded cork, and stick your subject on it. There is an advantage about this, which the simple pinning will not afford, and that is you may dissect your subject to the last piece without dragging it off the cork, which very often occurs through the pins on the subject giving way. Now having fixed your subject, insert the point of your scissors between any of the abdominal segments at the junction of the tergal T. C. WHITE ON INSECT DISSECTION. 37 witli the sternal surfaces and carefully slit up tlie integument, repeat the process on the opposite side of the body, and then raise it by holding it with the forceps and clearing away its attachments with the needle, you will then not disturb any of the subjacent visceral organs, but will see them all in situ. Having noticed their re- lations one to the other, proceed to isolate them by clearing away all the tracheal attachments with two needles — -a blunt one and a sharp one — and if done with a steady hand and a keen look out, no very great difficulty will be experienced in unravelling what before seemed a tangled labyrinth. It is sometimes a good plan after removing the integument from the sternal surface to place your subject in glycerine and water, and to leave it for 24 hours ; but in this matter I would leave the matter to every man's own judgment, for some- times I have found very good results arise from the simple dissection under plain water. We must bear in mind that we are working on tissues of great delicacy, and will do well to observe two precautions. Your instruments must be perfectly free from roughness, either aris- ing from patches of rust or burrs left after sharpening. I have often experienced great annoyance after making a delicate dissection that has consumed perhaps a couple of hours, and have taken up a flattened needle to it, and not detected some roughened spot till it has caught some of the fine fibres of my work, and then all was a hopeless mass of entanglement. Again in dissecting out the nervous distribution in insects the nerves will be found very fragile, and will scarcely bear the strain put upon them in clearing them from the surrounding tissue ; but the addition of a little alcohol to the fluid under which they are being dissected will harden them, and so pre- vent their rupture. This I have found a very useful agent in carry- ing out dissection; it comes in in all cases most advantageously, enabling you to isolate many organs, that without its aid would collapse and become, to coin a phrase, a mass of inextricability. The medium I have generally found most suitable for mounting specimens of insect dissection in has been glycerine. Nothing has shown them up to greater advantage, and I should recommend that in preference to anything else, as it maintains their transparency, while other preservative fluids make them dense and discoloured. With these few remarks I must close this short paper, hoping it may induce some one to take up this subject, and not only produce plea- sure in themselves but also add to our knowledge in this interesting branch of biology. 38 On Some Microscopic Tracings of Lissajous' Curves. By Robert G. West. (Read February 22nd, 1878/) In inviting your attention to the above subject, it is perhaps appro- priate to give you some facts of the history of these curves, to offer some explanation of their nature, and of the various contrivances for producing them, and to endeavour to show something of what has been previously done in microscopic writing and ruling. The earliest discovery of these curves of which I have been able to find any record, is that of Mr. Sang, of Edinburgh, made about forty years ago. Mr. Sang embodied his results in a contribution to the Edinburgh Philosophical Transactions, entitled " On the Vibration of an Elastic Spring." About two years afterwards Mr. Perigal followed in the same line with his " Kinematic Curves." In 1844 Professor Blackburn, of Glasgow, invented a form of pendulum capable of swinging in two planes, the curves produced by which were recorded by a fine stream of sand falling from the pendulum- bob, and were similar to those afterwards produced by Lissajous. In the " Annales de Chinicie et de Physique" for 1857, Lissajous con- tributed the results of his investigations, which had chiefly an acoustical bearing, and were conducted by means of mirrors attached to tuning-forks and reflecting a beam of light, so as to produce, by the persistence of the retinal impression, a continuous curve, characteristic in each case of a particular ratio of the fork-vibrations. In 1871 Mr. Hubert Airy was independently led to the discovery of these curves by observing the accidental gyrations of an acacia- shoot. Mr. Airy narrated his experiments in two very interesting papers in Nature for the 17th August and 7th September, 1871, and has given a lucid analysis of the figure produced by nearly coincident vibrations. I have made some experiments with the apparatus devised by Mr. Airy and Mr. Routh ; but that described by Professor Swan, of the University of St. Andrew's, in a letter appearing in Nature for the 7th September, 1871, seems better, as R. G. WEST ON LTSSAJOUs' CURVES. 39 being free from the tendency to twist, and so alter the relative lengths of the pendulums ; also as eliminating any real or apparent effect of unequal lateral tension of the strings. I believe the next stage was Mr. Tisley's happy combination of the movements of two separate pendulums in a single point, as described by him to the British Association in 1873. Following this was an exact and scientific explanation of the curves by Dr. C. Giebel in the " Zeit- schrift fur die gesammten Naturwissenschaffen," Bd. xiv., October, 1875. In the "Loan Collection of Scientific Apparatus," in 1876, an instrument embodying some new features was sent by the Institute for Physical Science of the University of Halle ; and later, Mr. Browning has introduced a cheap form of the apparatus, which he calls the Sympalmograph, and has issued an interesting pamphlet in connection with it. There is also a description of Mr. Tisley's machine in " Engineering" for the 6th February, 1874, and he has since produced a cheaper form of it. I will proceed to describe briefly the Compound Pendulum Apparatus, by which these curves, in their ordinary form, are produced. Two pendulums are sus- pended so that their planes of vibration are at right angles to each other. From a point in each pendulum above the point of suspen- sion there proceeds an arm, connected at one end with the pendulum by means of a ball-and-socket joint, the other extremities of these arms meeting in a glass tube-pen, which traces a line representing the resultant of the motions of the two pendulums. This is sub- stantially the instrument as originally brought out by Mr. Tisley. In Mr. Browning's Sympalmograph, the details differ in several re- spects, chiefly in the connecting arms being attached by means of a Hook's universal joint below the points of suspension of the pendulums. If either pendulum is set vibrating separately, the pen will trace an arc of a circle, of which the radius will be the arm attached to the other pendulum, and the centre the point of that attachment. For the present let us consider these as straight lines. Now, suppose the pendulums adjusted to vibrate exactly in the same periods of time, or, as it is usually put, tuned to strict unison, and that they are started exactly together. It is clear that the pen will trace a diagonal line, the resultant of the rectilinear motions, and this line will be repeatedly retraced as the vibrations die away. The angular direction of this line will vary according to the relative ampli- tude of the vibrations of the two pendulums. Directly, however, you leave this simple set of conditions, by starting one pendulum 40 R. G. WEST ON LISSAJOUs' CURVES. after the other, by making their times of vibration unequal, or by combining the two expedients, the result is more complicated. If two equal pendulums be started, the one half a vibration after the other, a circular spiral, and with any other fractional start an elliptical spiral, more or less oblong, will be produced ; thus the ratio of 1:2 (illus- trative of the musical interval of the octave) gives, with a simul- taneous start, an approximation to a parabolic curve ; with the half- vibration start, the figure 8. With the higher ratios (2:3, 3:4, 4:5, &c), the effect of throwing the vibrations " out of tune," as it is called, so as to let one pendulum gain on the other, is to pro- duce a more or less confused figure ; but, with the simple ratios of unison and 1:2, very curious and beautiful effects are thus ob- tained, resembling in some cases the markings of Diatoms. By a very slight discordance in the vibrations, however, u water-markings" are produced, which constitute the chief beauty of these curves. Similar "water-markings'' are obtained by the superposition of figures as nearly similar as can be traced, and in both cases the ex- planation lies near the surface. With the unison made so discordant as 29:30, a very curious stereoscopic effect is produced, resembling a piece of network hanging in folds. But with the apparatus which I have described, none of the figures are strictly symmetrical, all being resultants of two arcs and not of two straight lines. The distortion, however, may be largely reduced by lengthening proportionately the connecting arms. It was entirely obviated in the Halle apparatus referred to above, an instrument designed by Herr P. Schasnemann, and made by Kleeman, of Halle, in which the tracing-point was actuated by one pendulum only, while a glass tablet, carrying the card, and suspended by an elaborate system of cords, was impelled by the other ; by varying the angular inclination of the vibrations, curious skew and scroll-like figures were produced. Beautiful spiral figures are also obtained by rotating the card by clock-work. With the subject of microscopic ruling and writing, I cannot deal completely, owing to the scattered nature of its literature. The finest rulings, prior to 1851, which Ihave found recorded, are those of Fraun- hofer's fixed net micrometer for the telescope, and Sir John Barton's rulings on steel, which were both at the rate of 10,000 to the inch. Impressions of the latter were taken in gelatine, to serve as micro- meters. In 1851, Mr. De la Rue exhibited 10 groups of rulings varying from 11,261 to 56,306 to the inch. Mr. W. Chandler Roberts, of R. G. WEST ON LISSAJOUs' CURVES. 41 the Royal Mint, has shown fine lines ruled on gold, rivalling the diamond in brilliancy of colour. At the International Exhibition of 1862, Mr. Lendy, Engraver to the Royal Mint at Turin, ex- hibited some specimens of reductions on silver and steel effected by a machine which would reproduce, on a scale of xV^h, designs vary- ing in size from 7*87 inches to -039 inch in diameter. As an instance, a coat of arms containing the letter R, surrounded by a Gothic frieze, was engraved on steel in a space -013 inch in diameter. Mr. Webb also showed a reducing machine at the Exhibition of 1862. An account of Mr. Stanistreet's Micro-rulings on glass and steel, and of his instrument for producing them, will be found in the " Monthly Microscopical Journal" for 1871, Vol. vi., pp. 151, 274. In the "Monthly Microscopical Journal" for 1874, mention is made of a Lord's Prayer written by Mr. Webb in a space of ^^th inch x xi r th inch, these measurements being verified by Colonel Woodward. This, it was stated, could be easily read with a good 1 inch objective and central light. The only record of the scales of M. Froment, of Paris, that I have met with, names them as ruled to 5I i M inch. M. Froment was celebrated for his microscopic writing, the inspection of which it was that incited Mr. Peters to construct his machine, beautiful and celebrated both in itself and in its results. This machine was des- cribed by Mr. Farrants in the " Transactions of the Microscopical Society" for 1855 (Vol. III. N.S.). Its power of reduction could be varied at will as far as 6,000 times linearly. By its means the beautiful bicircloids of Mr. Perigal were produced in circles the ^th inch in diameter. Among specimens of its performance may be mentioned the inscription of the Lord's Prayer (ending with " deliver us from evil ") in a space -3 g-g-Voo^h sc l nare inch. This is at the rate of over 22 Bibles to the inch. The machine, together with Ibbetson's Geometrical Chuck, was presented by Mr, Peters to the Royal Microscopical Society. A Lord's Prayer is mentioned by Mr. W. Webb, as in the possession of Mr. Frank Crisp, as being written at the rate of over 59 Bibles to the square inch. The average space covered by each letter of this marvellous specimen is said to be tne 21 000000 o tn °f a sc l uare inch. We now come to the still more wonderful rulings of M. Nobert. With reference to these I would remark that in nothing that I have read about them have I seen mention made of any claim by M. Nobert to absolute uniformity among his various plates ; and I am 42 R. G. WEST ON LISSAJOUS' CURVES. told by one of the leading opticians in London that, as a matter of fact, they are not uniform. If this be so, it would seem that there has been some waste of discussion upon them. If they are uniform, it is surprising that M. Nobert should not have published the autho- rised version of their various scales, which his machinery would enable him to supply. There are two papers on Nobert's plates which are of much interest, the latter from the mechanical, rather than the optical point of view ; one by Mr. J. A. Brown, F.R.S., read before the Royal Society, and reported in No. 163 of its Pro- ceedings, extracts from which paper are given in the " Monthly Microscopical Journal" for June, 1876 ; the other, a paper by Mr. Wm.A. Rogers, in the "Monthly Microscopical Journal" for August, 1876. Mr. Brown gives elaborate measurements taken from paper- photographs produced by Dr. E. Curtis. From these it would seem that in the 15th band the widths of the lines, and of the spaces between the lines are equal, viz., the yWa^o^h mc h. Materially finer lines than these cannot, it is said, be drawn under M. Nobert's pressure without the graving-point sliding into the previous grooves. Mr. Rogers' estimate of the width of the lines in the 19th band is iiwoo^ 1 inch, his own finest rulings being the TB a th inch wide. Mr. Brown quotes the statement that lines T 6 ' th inch are visible with a power of 125, and countable with a power of 160 (the stand- ard of comparison with the naked eye being taken at eight inches). Mr. Rogers gives the eye much greater power. He states that a single line, 3 ^gth inch wide, filled with plumbago, can be seen at seven inches from the unaided eye, or, if reflected irom a silvered surface, at 11 inches. The former distance gives an angle of vision of 1" ; the minimum angle being, according to Dr. Royston-Pigott, 6", and, according to other writers, 1' to 2'. Mr. Rogers places the limit of visibility beyond the -^ Jo^tli inch. He says that he despairs of ruling 100 consecutive lines with a less error, individual or accu- mulated, than the ^oaoo^ 1 mcn j an( l puts the usual range of error in stage-micrometers at from goVo^ 1 ^ loljou^h mc h> which seems high, especially if referring to the thousandth divisions. He also speaks of a grain in polished crown glass which causes lines sometimes to become enlarged in width, and sometimes to become serrated at the edges — if 25,000 to 30,000 to the inch, at once; if of coarser ruling, after a time. In two instances the disruption occurred under his actual observation. Such merit of fineness or delicacy as may attach to the tracings R. O. WEST ON LISSAJOUS' CURVES. 43 I have made is largely due to the excellent diamond point for which I am indebted to the kindness of Messrs. R. and J. Beck. This very delicacy is, however, in some cases a drawback, as it increases the difficulty of obtaining an illumination, which will show the figures in a striking way. Some of the lines which I have obtained have been measured by Mr. Webb as 55,000 to the inch. I have cut a few specimens more deeply, and they undoubtedly " come out " better, and even brilliantly, but they are necessarily coarser in line, and more widely spaced. A point of interest with respect to these curves is their possible value as test- objects ; and Mr. Wenham, to whom my acknowledgments are due fur many practical and valuable suggestions, tells me that some of of them are quite sufficiently closely ruled for this purpose, and he considers that the intersection of some of the lines, and the gradual approximation of others, gives them a value above that of parallel rulings. With reference to this, I may mention that in some of the figures every degree of sharpness of curve is obtainable, from a line returning almost upon itself, at an exceedingly acute angle, to curves so flat as to present in parts virtually the appearance of parallel straight lines. Another point is that, unlike diatom-markings, which, after abundant controversy, can hardly yet be said to be indu- bitably understood, the nature of all lines cut in glass may, up to a certain point, be said to be known. It seems clear, from the nature of the case, that they must be formed by some such V-shaped grooves as are illustrated in section, thus : — y — y — y — though, whether, in traversing transversely such a series of ridges and furrows, the trac- ing-point descends into the furrows, I cannot positively say. From some appearances which I have observed, I am inclined to think that the point leaps from ridge to ridge ; but I believe the apparatus could be modified to produce with certainty a vertically waved line, if desirable. A curious feature in some figures is that though all the lines would seem to be in the same plane (except in so far as affected by the consideration just named), it sometimes happens that an alteration of focus is requisite to bring out the transverse lines. I should mention that, with one or two excej>tions, each of the figures is a single continuous line from beginning to end. These exceptions consist of one figure super-imposed on another. I have alluded to the difficulty of exhibiting these objects. They are almost drowned in the glare of direct transmitted light. For general effect Mr. Curties, who has devoted not a little time and 44 E. G. WEST ON LISSAJOUS' CURVES. study to the problem of their illumination, has found nothing so good as a brilliant dark-ground illumination by a large spot-lens. The difficulty in this case is to get a sufficiency of light with a really black ground. For the exhibition of " water-markings," a uni- lateral oblique light is advantageous, and is, perhaps, best obtained, as suggested by Mr. I. C. Thompson, of Liverpool, by stopping out •^ or |rds of the hollow cone of rays given by dark-ground illumi- nators, so as to secure a crescent of rays. Complete rotation of the object is necessary to obtain all the " water-markings " characteristic of the more complicated curves, and of superposed spirals. Good effects are sometimes to be obtained with reflected light, and many of the figures have a singularly solid or scroll-like appear- ance, which, though sufficiently striking under the monocular, is enhanced by the binocular microscope. I have traced a few curves, at Mr. Wenham's suggestion, on polished steel. These to the naked eye, or under a low power, have a brilliant iridescent appearance, but are not remarkable when more highly magnified, as the best steel surfaces which I have been able to procure are far too rough for any effective work of this kind. There is some difficulty in effectively mounting the glass-tracings. Dry-mounting is, of course, the only available method. Both dust and wiping have to be avoided ; while it is necessary to defer the actual covering till the cement-ring is so far hardened that no " damping " whatever can take place. Any condensation of vapour beads the cut lines, and, in the most searching way, brings into view defects of surface-polish, otherwise quite invisible even under a good dark-ground illumination. In conclusion, I think I may claim for these tracings some special interest ; mechanically, as successful examples of minute diamond- graving under somewhat new conditions ; microscopically, as test- objects, and as affording studies in illumination and in certain para- doxical and deceptive appearances ; and aesthetically, as even surpas- sing in beauty and brilliancy, and especially in stereoscopic effect, the larger curves which are so well-known and so much admired. 45 On a New Micrometer. By George J. Burch. (Communicated by Mr. T. Curties ; Bead March 22nd, 1878.) Plate IV. It is not every Microscopist who can afford a thoroughly efficient Micrometer, and it is not always that the possessor of one can find time to use it. A really good working Micrometer should bear the same relation to the microscope that the two-foot rule does to the carpenter's bench — it should be both cheap and handy. The spider-line Micrometer costs quite half as much as a good many people lay out on their microscopes, and the cheaper eye-piece scales used in its stead are at best only adjusted for one particular power, while for all others they are about as handy as the car- penter's rule would be if its measurements had to be reduced to inches by a table, or by Rule of Three. The result is that nobody uses a Micrometer if he can help it, unless he has nothing else to do. What is wanted is a Micrometer that shall 1. — Cost but little ; 2. — Measure accurately with any power ; 3. — Read in decimals of an inch or millimetre, without any calculation ; 4. — Apply equally well with all kinds of illumination ; 5. — And take no more time to put on than the mere changing of an eye-piece. To invent such a Micrometer is a problem which I have had before me ever since the summer of 1872, and I now submit to you an instrument which bids fair to solve it. Noticing one day some scratches on the lamp glass, focussed by the achromatic condenser, it struck me that I might use the image of a scale on glass formed in the same way as a Micrometer. I saw that I could easily adjust the size of this image to coincide e 46 G. J. BURCH ON A NEW MICROMETER. with the divisions on the stage micrometer, by altering the distance between scale and condenser. But this was a troublesome operation, until I fixed the scale in a tube sliding below the lens — and then the divisions had to be so much smaller, that with my appliances I could not get them accurate. And, besides, it was of no use with large objects or front light, so I gave it up. However, I showed the principle, in a rough way, at a meeting of the Quekett Microscopical Club, on October 25th, 1872, and was somewhat surprised, a few months later, to find, from the Paper on the lC Aerial Stage-Micro- meter," published in the " Monthly Microscopical Journal " of January, 1873, that Dr. Royston-Pigott had been working in the same direction.* Dr. Pigott's paper so completely detailed my principle that I determined to abandon it altogether, and seek " green fields and pastures new." So I looked into the theory of the various forms of Micrometer. The early microscopists aimed at getting micrometer and object in the same plane, and so laid the object upon the scale itself, in the lower focus of the objective. The next step was to place a real scale, or spicier lines, in the image at the focus of the eye-lens, that is to say, in the upper focus of the objective. Browning, in his spectroscope, employs the image of a scale in the same place. Then the Aerial Stage-Micrometer reversed the operation with an image of the scale in the plane of the object, formed in the light, before it entered the instrument. In the two foci of the objective all possible variations of real scale or optical image had been used. But every lens has its two conjugate foci. One focus of the eye- piece coincides with the upper one of the objective, the other re- mained. It is only a virtual focus, for its sign is negative. It had not been used, that I know of, except indirectly, for micrometry. I wanted a novelty, so I varied all the conditions, and determined to unite an image of the scale, with the image of the object, after it had left the eye-piece. At first I proposed to use the glass scale and lens of my aerial stage micrometer, with a diagonal tinted- reflector fixed above the eye-piece — like a camera lucida set back- wards. But just then I had occasion to investigate for another pur- pose the theory of the apparent distance of the magnified object. I found that as the focus is altered so the plane of the image varies * A micrometer identical with Dr. Pigott's " Aerial Stage-Micrometer " will be found described in " Goring and Pritchard's Micrographia," 1837, p. 51. (Ed. Q.M.C.J.) G. J. BURCH ON A NEW MICROMETER. 47 from the nearest limit of distinct vision to infinite distance. Then why not dispense with the lens altogether, and compare the reflection of the scale itself with the object, adjusting its distance till the divisions on it coincide with those on the stage-micrometer ? At first it seemed as if it would be hard to compare the reflection of a real scale with an optical image, but it soon proved otherwise. Just as in the camera lucida, you see the image of the object thrown on the paper, and may measure it upon a scale drawn there, so here you see the reflection of the scale in the field of the microscope, and may compare it with the object. This, then, is the principle of the new Micrometer. Briefly, it is an inverse application of the camera lucida, coupled with the direct use of a scale, the graduations of which are adjusted to size by vary- ing its distance from the eye-piece. In its simplest form, which I prefer, the instrument consists of a cap, A, slipping over the eye-piece, and carrying an arm, B, on which slides a clip, C, to hold the scale, D. The reflexion of this scale is thrown into the eye by the diagonal glass, E, and compared with the object seen at the same time through the eye-piece, F. (Plate IV.) It may be objected that this is a heavy side-strain for the tube. Practically, I have not found it so, but the stem may be brought parallel with the tube by using a second larger mirror of looking-glass as in the second figure, or, the whole thing may be made smaller by having a lens to form the image of the scale. But then the instru- ment loses its simplicity, and is not so easy to use. The stem should be about 10 inches long, and should be made to unscrew. Then, as to the reflector, I find thin cover glass gives a double image. Sommering's steel disc, the camera lucida, or Dr. Beale's neutral tint glass, answer equally well ; but for some pur- poses I should give the preference to a piece of looking-glass with the amalgam scraped off in the centre. If silvered glass is used, a tiny drop of nitric acid from a capillary tube will eat the requisite hole very cleanly. In this case the second image is completely overpowered by the superior brilliancy of the reflection from the silvered surface. The scale may be copied from any graduated rule — millimetres are a convenient size — the length of the stem giving plenty of latitude in this respect. It may be drawn on ivory or card. A barometer scale, with its vernier, answers admirably — there being so few divisions, the eye is not confused in counting them — and it is 48 G. J. BURCH ON A NEW MICROMETER. very accurate. All but the scale itself should be blackened. For some very brightly lit objects a transparent scale is useful, while for very faint ones, or for front light, a white scale on a black ground, or lines engraved on a polished strip of German silver, and illuminated by oblique light, may be employed. This last is the best for star measurement with the telescope — the delicate silvery lines standing out with peculiar distinctness, and without interfering with faint stars. Advantages of the New Micrometer. It is easy to make. Any one who possesses a Beale's Neutral Tint Reflector may adapt the New Micrometer to it. To adjust the scale (which should be numbered with the figures reversed) , so that it may read decimals of an inch or millimetre, &c, use a stage micrometer, set the instrument in position, and slide the scale along the stem nearer or further from the eye, as it may require, till on adjusting the focus so that the apparent distance of the two images may coincide, every 10th division on the scale shall cover the l-100th or 1,000th of the stage micrometer, according to the power used. Then mark the position of the clip on the stem with a file. This position should be found for each objective with each eye-piece ; the higher the power, the more delicate is the measurement. To the optician, the construction of this Micrometer offers no difficulties. There is no screw to make accurate in thread and in bearing — no microscopical scale to engrave. It is made in the way that is most convenient, and afterwards adjusted to the required standard. It is easy to use. The Micrometer, with its scale clip set to the mark corresponding to the power employed, has only to be slipped on in place of the ej^e-piece cap, and the measurement made by inspec- tion. If the object does not lie in the right direction, twist the clip on the stem, and the image of the scale will revolve in the field of the microscope, so that it can be set exactly across the object. If the light is too strong to permit the scale to be seen, the lamp may be shaded with one hand, while the stage and focussing is managed with the other. Then there is no calculation required. The stem may be marked to read fractions of an inch, a line, or a millimetre. As regards accuracy, I do not pretend that it will supersede the Spider-line Micrometer. But as far as all scale micrometers are concerned, it is not inferior to any. For it will fill the field with G. J. RURCH ON A NEW MICROMETER. 49 divisions as fine and as close as can be distinguished at ten inches, and no scale can do more. But it is hard to get an eye-piece Micro- meter that reads exactly thousandths, and even then it is only with one power. The Aerial Stage Micrometer, like this one, has an adjustible scale, but on account of the lens being used to produce the image, any error in the setting will make five or six times the difference that it would in mine — in which the error of measurement is the same fraction of the object that the error of setting is of the length of the stem used. The personal equation, too, is evidently elimi- nated if the microscopist himself adjusts the setting by an accurate stage micrometer. But its principal advantage is found in the number of uses to which it may be put. When the stem is unscrewed it leaves the camera lucida intact. The clip will carry a Goniometer — simply a black index, like a watch-hand, with parallel sides, re- volved by a button from the back in a graduated semicircle — the diameter being drawn specially broad for distinctness. It is as easy of application to a hand-magnifier as it is to a microscope. I use it with my dissecting lens, and even with my diatom-finder — a Coddington, of l-20th of an inch focus. For more than a year I have had one fitted to my small lathe, and have rejected the ordinary gauge in its favour. The metal seems to melt away under the tool by thousandths at a time, down to the required size on the scale. My experience of it is that it would be invaluable to the optician or watchmaker ; it reduces the chance of going too far, and saves a deal of time. Then with the Spectroscope it is quite as easy of application, and as comfortable to use as Browning's arrangement. I have already mentioned the scale engraved on silver and illu- minated by oblique light, as being best for astronomical use. It is sj^ecially adapted for star-spectra — a slight shading of the dark lantern reducing the brilliancy of the lines to any extent without impairing their distinctness. Nor is this all. Not only can this Micrometer be applied to any and every kind of optical instrument, but it can be used by itself for many things that neither carpenter's rule nor callipers can reach. You have only to fit a rod ten inches long in place of the microscope tube, and set the scale ten inches from the reflector, and you may measure the size of anything in the plane of the end of the rod. The internal diameter of a soda-water bottle — the contraction of the iris in a strong light — the diameter of a dew-drop — or the sweep 50 G. J. BURCH ON A NEW MICROMETER. of a bee's wing as it hovers over a flower — in fact any of the thou- sand and one odd things that are commonly supposed to interest the man of science, maybe determined by this simple arrangement. And I think it not unlikely that it may prove useful to the surgeon, in conjunction with the laryngoscope, as a guide in preparing for an operation. During the four or five years that I have had it in use I have found it so handy and useful that I determined to show it to Mr. Curties, and ask his opinion. He at once gave a favourable judg- ment — kindly offered me every assistance and encouragement — (for which I heartily thank him) — and has undertaken, not only to read this paper before you, but also to provide one of the new Micrometers for presentation to your Society. I am aware that the very simplicity of this instrument is preju- dicial to it at first sight. There is no mystery of tubes and lenses about it to give it dignity. It looks make-shift rather than scientific. But a little thought will show that it is correct in theory, and a little experience with it will reconcile all who value time and money to its appearance. And I doubt not that, in abler hands than mine, the new principle that it involves will lead to useful, and perhaps more important results. 51 On a Method of Mounting Whole Insects Without Pressure for the Binocular Microscope. By Staniforth Green. (Communicated by Mr. T. Curties ; Read March 22, 1878.) Minute Hymenoptera (Iclineumonidse, Chalcididae, Proctotrupida?, &c), require little manipulation to render them fit for mounting in Canada balsam, and they are easily collected. I have captured numerous species in Ceylon by sweeping the grass with a small bag net, about Sin. in diameter at mouth, and tapering down to a point at bottom. It should be made of fine cambric, as many of these small insects do not exceed the ^ ¥ of an inch in length. About a dessert-spoonful of spirit of turpentine should be placed in an ordi- nary wine glass, over which the net is to be drawn after a sweeping operation. While this is being done, the captured insects must be confined to the bottom of the net by gathering the net between the thumb and finger at about one inch from its bottom. When it has been drawn over the glass as far as it will go, then the thumb and finger must be removed, and the insects allowed to fall into the turpentine. They will quickly die, mostly with outspread wings and legs. Minute species should be fit for mounting after they have remained in turpentine for a few days. This treatment, however, will not succeed with more horny kinds, which, when thrown into turpentine or spirits of wine, curl themselves up in dying, and can- not afterwards be straightened out. Insects of that class should be placed alive on a piece of glass, and while walking, a thin covering glass can be let down upon them. Strong sj^irits of wine must be quickly introduced between the two glasses by means of a camel's- hair brush. This soon kills the insect in the position of walking, and it should be kept so in spirits for at least six hours. I use the ordi- nary 3x1 inch slip and a good sized covering glass — the heavier the better. Seven or eight sjDecimens can be so arranged on one slide, which may be placed in a saucer containing sufficient spirits of wine just to cover them. They can afterwards be transferred to turpentine to render them fit for mounting in Canada balsam. 52 8. GREEN ON A METHOD OF MOUNTING WHOLE INSECTS. Dipterous insects of moderate size may be treated in the follow- ing way : — Catch them alive and hold their wings between the thumb and finger. Thus secured they should be dipped in turpen- tine, and held in it until quite dead. When released they will be found with elevated wings and folded legs. Let them remain undisturbed in the turpentine for five minutes or so. Then take them out and hold them by the wings while you arrange their legs under a magnifier, using a needle or a pair of fine forceps with a light hand, as legs come easily off. Replace them in the turpentine for a few minutes, and then transfer them to a small glass test tube one-third full of turpentine. Hold the tube over a spirit lamp till the turpentine commences to boil. Then examine with a magnifier the insects in the tube. If cooked enough, tongues will be found protruding from their mouths, forced out by the action of the hot turpentine. The ovipositors of female insects are also similarly displayed. This process much hastens the preparation of insects destined to be mounted in Canada balsam, but they must not be overcooked, as with prolonged boiling they are rendered too brittle and transparent. After removal from hot turpentine they should remain in cold turpentine until they become tolerably transparent, with a perfectly clean outline. Spiders should not be boiled in turpentine. Kill them in spirits of wine, and then place them on a piece of glass,* and arrange their legs and antennas in proper position, or as near as possible. Then wind a piece of fine sewing silk or thread round the glass in a way to keep the legs in the position they have been placed. When the winding has been completed, twist the ends of the thread together to keep them fast. Then place the piece of glass with the spiders on it in turpentine, and let it there remain until the spider becomes sufficiently transparent. I have sometimes first placed the bound spider in spirits of wine for a few days, and afterwards in turpentine, to render it more quickly transparent. In my opinion the advantages gained by preparing insects in the way I have described are that they do not alter in figure, or very little so ; that their muscular structure is well shown, their eyes, tongues and ovipositors nicely displayed, and preparation easy of management after a little experience. I uauauj cuo siuiabie pieces from rejected slips. 53 On Variation in Spongilla fluviatilis. By J. G. Waller. (Read April 26th, 1878 J Plate V. On a former occasion, I gave the result of some observations on the two British freshwater sponges. My present remarks will be confined to Spongilla fluviatilis. Dr. Bowerbank, in his admirable work on the British Spongiadaa, the result of a long life of research, makes the form of the spicule of the skeleton, membranes, &c, one of the distinctions of species. It is not only convenient, but, as an important part of the anatomy, a necessary item in the task of classification. But a question arises to what extent this is to be used : for the tendency to multiply species, though it has long obtained amongst naturalists, presents a formidable barrier to the student, in the large increase of terminologies, which, in their varied combinations, seldom convey any idea to the mind. It is, however, with some diffidence that I enter into so important a subject, and it is not by any means to disparage the many eminent men, who have done so much to advance our knowledge of natural history. But I feel it is forced upon me, either to protest against the excess of this practice, or to follow it myself. The latter I cannot do until the question is settled, whether it may not be as easy to combine under the title of " variation," instead of making a divergence under the name of " species." In the third volume of the " British Spongiadee " Dr. Bower- bank has introduced us to two new species of native Spongilla?. Both were found in the river Exe, or reservoir in connection with it, by Mr. Edw. Parfitt, of Exeter. One of these he has named S. sceptrifera, on account of its membranes having a small spicule, suggesting the sceptre-form character. One specimen of this only having been found, and that without the ovaria, which usually dis- tinguish the Spongilla, our knowledge of it is at present limited. But the other nearly resembles, in all its characters, usual specimens 54 J. G. WALLER ON VARIATION of S. jluviatilis, yet it differs from that which is described by Dr. Bowerbank, as typical of the species, in some minute particulars, to which I shall particularly direct your attention. The specimen described as the typical Spongilla Jluviatilis, was found in the West Country Timber Dock, at Rotherhithe, and its characters are thus tabulated : — Sponge massive, sessile ; surface uneven, often lobular, hispid. Oscula simple, large, scattered. Pores conspicuous ; dermal mem- brane pellucid, aspiculous. Skeleton ; spicula acerate ; ovaria sub- globose ; spicula birotulate, short, rarely spinous ; disposed in lines radiating from the centre of the ovarium ; rotula equal in size, flat, deeply and irregularly dentate, diameter equal to the length of the shaft of the spiculum. Now the difference between this description and of that of the river Exe, is, that the skeleton spicules of the latter are of two kinds — one smooth as before, the other " incipiently spinous " — both irregularly mixed in the skeleton, but the latter fewer in num- ber. The spicules of the ovaria are, more or less, spinous ; spines long and acutely terminated. Mr. Parfitt, in a letter to Dr. Bowerbank, stated that he considered the species as intermediate between S. Jluviatilis and S. Meyeni of the Bombay tanks. Mr. Carter, descrit ing it in the "Annals and Mag. Nat. Hist." April, 1868, calls it S. Meyeni, var. Parfitti. His description is fuller than that of Dr. Bowerbank, and I shall refer to it again. He appends the following observations : " This Spongilla chiefly differs from Sp. Meyeni, of Bombay, in the decidedly spinous character of one-third of its largest spicules, while about the same proportion in the Bombay species can only be termed ' incipiently spinous.' The excess of size of the elementary parts generally of the Bombay species over those of the variety in the river Exe amounts to nothing specifically considered." " But there is a much more decided difference between var. Parfitti and the birotulate English species Sp. Jluviatilis, which also grows in the river Exe, inasmuch as the spicules of the skeleton of the latter are all smooth, the shaft of the birotules somewhat constricted in the centre, approaching to the hour-glass shape, with the margin only of the rotules minutely dentate, almost fringed." Now, it is necessary to observe, that the claim of the Spongilla of the Exe to be a new species allied to that of S. Meyeni is pointed out to be the spinous condition of a portion of its spicules, but it is IN SPONGILLA FLUV1ATILI9. 55 the last which has what may be truly called spicules " incipiently spinous ;" for this character can only be discovered by the use of a £th objective. Upon this, Dr. Bowerbank observes " How this British Spongilla can be a variety of a species that does not exist in England, or to the best of my knowledge nearer than Bombay, is quite past my comprehension ; and I have, therefore, described it as a distinct species, under the title of S. Parjitti" Before we consider the value of these differences, let me direct your attention to specimens found in the Thames, all of which differ from the described type, and some in their minute structure seem to be identical with that found in the river Exe. Neither Dr. Bower- bank nor Mr. Carter can have been acquainted witli the Spongilla of the Thames, or they could not have avoided noticing the interest- ing variations from the established type. Indeed, almost all the characters set down are found to vary. First, as to the dermal membrane, which is pronounced to be without spicules, I can show you a specimen in which this organ is completely covered with spicules, matted together. Then, as regards those of the skeleton, examples are met with in which a portion of them take the " in- cipiently spinous " condition of that found in the Exe, and others pass from that into a greater development, so that more than one half of the spicules of the skeleton are spinous, and the spines well pronounced, until we reach the climax in which all are spined, with only here and there a representative of the smooth type-form. Passing from the Thames, out of which, as yet, I have not obtained a single specimen of the so-called type, I shall show you an example in which, though the spicules are smooth, yet both dermal and interstitial membranes are thickly provided with them of a slender, delicate and special character. It will then be a question to ask whether, following precedent, we are to establish three or more species ; or, whether it is not more in the interest of science to take a different course, and to endeavour to embrace, under the general title of Spongilla Jluviatilis, all those which possess characteristics typical of the species ; and especially in the birotulate forms of the spicules of the ovaria, noting, if you please, the varieties by either an additional name, or what would equally satisfy, in my opinion, all that is required, an addition of A, B, or C, &c. Surely it must be rather misleading than otherwise to have such a title as " Spongilla Meyeni, var. Parjitti ," or even 56 J. G. WALLER ON VARIATION S. Parfitti alone, applied to a slight variation. But if we retained "fluviatilis " we should naturally infer, whatever additions we gave, that it recorded a variation only from the known type ; and it may be that these observations might be extended even to some of the exotic species, for the multiplication of terms is in itself an evil, threatening to make us little better than walking catalogues. Now the first of the Thames S. fluviatilis to which I shall call your attention is that found in Tecldington Lock, because this comes as near as possible to that from the Exe, to which I have referred. In external appearance it partakes of the foliate or lobate form of one of the exam]3les engraved by Dr. Bowerbank, Vol. iii, p. 295, fig. 7, but this is very common to the genus. The spicules of the skeleton are chiefly of the ordinary smooth type, acerate ; but among these is a variation almost cylindrical, the terminations being acutely pointed, making the whole not unlike a lead pencil, sharpened at each end. It is not, however, common only to this, as it occurs, though in a less degree, in most of the species. The rest of the spicules, perhaps about one-third, are spinous, like that of the Exe, sometimes slightly so, but some have the spines well developed. It is an interesting fact to which I must syjecially direct your attention that the growing fibres of the apices of the sponge have all the spicules smooth, and it is only as we proceed downward towards the base and older parts that the spinous character is produced. This in itself gives us a clear hint that the latter belong to a development which other examples, soon to be described, have carried still further. An abnormal form, which has often been found in the species, I have only found here. It is a spicule, somewhat sym- metrical, having a central inflation, often two, and even three, and found dispersed throughout the tissues. I record it merely as a form, in which the Spongilla sports, not as having any specific value. As regards the birotulate spicules they accord with that from the Exe, being exactly the same size, viz., ^Vo °f an inch, hut I have not found the shaft so frequently spined. (PI. V., fig. 1.) Leaving Tecldington Lock, we will proceed to that of Molesey, near Hampton Court, where this Spongilla grows in luxuriant abundance. Nowhere else have I seen such fine specimens. Here I have never seen the foliate condition, for the maturely developed sponge has a generally even surface, undulating slightly, but showing no differences from that which is typical. It is when its structure is examined under the microscope that its interest begins. Rising IN SPONGILLA FLUVIATILIS. 57 as it does from the broad base of the lining boarding of the Lock, its growth is regular and symmetrical, as shown in its network. In a vertical section this is well demonstrated, and we find that nearly all the spicules thus seen are spinous, the spines being well developed. But if we get a horizontal section this is somewhat reversed, and the smooth spicule is then predominant ; and when we give a closer examination into these constituent elements, it is found that there is about an equal division as regards numbers, and that half the spicules are spinous, and half smooth ; the latter generally a little longer. As regards the birotulate spicule of the ovarium, it is in all respects similar to that of Teddington (fig. 2). Let us now retrace our steps, and row back through that pretty part of our beautiful river, from Hampton to Surbiton ; a trip at all times enjoyable, not even wanting the good excuse of the naturalist. Here, by the little eylet occupied by Messenger's Boat- house, &c, both our native Spongillas are found in abundance. They grow on the moored barge-house, beneath the floating baths, and all round the wharf-boarding, in various stages of development. But the specimen to which I draw attention was attached to the floating barge, on the side towards the island, between which and it was but a small interval shaded from light. And, close by its side also grew S. lacustris, overlapping it in places ; and so much alike, in every external character, that, without a lens, no distinction could be made between them ; the branching form of the latter being wanting. It was a rebuke to naturalists in its name, so untrue as the Lake Spongilla, when flourishing under precisely the same conditions as S. Jiuviatilis, but also assuming its shape ; showing, that their law, at least, must not be like that of the Medes and Persians, which altereth not. The first point which close observation brings to notice, is, that the hisjnd character, which generally marks this Spongilla, was wanting ; but, in place, was a felting of spicules on the dermal surface. It is a condition not hitherto observed. More intimate knowledge obtained by sections and close examination of the spicules reveal the fact of a still greater development of the spinous charac- ter, as the smooth type has all but vanished, leaving only here and there a representative. As regards the birotulate form there is no change, as it conforms to the two last (fig. 3). So, here then, we have travelled the circle ; beginning with the smooth spicule of the type, we end by finding it yield place to the 58 J. G. WALLER ON VARIATION spinous one, and become practically obsolete. Place the two extremes side by side and the divergence is great ; follow the development through the Teddington and Molesey examples, and the connection is clear enough. Nor are the localities cited the sole places on the Thames in which these varieties are found. At Cleeve, in Oxfordshire, is a parallel to that of Molesey ; whilst at Goring, in the same county, we get that of Surbiton. But, as yet, the Thames has not furnished me with a single example coinciding with Dr. Bowerbank's type found in the West Country Timber Dock, and that locality has failed to give me a specimen. But the river, nevertheless, has given one with the smooth spicule only, but it provokes us, by not adhering to the type ; so even now we do not get rid of variation. This is a parasitic form, found at Henley ; not, however, in the full flow of the river, but in a small side creek ; a difference of condition which should always be noted, although at present we may not be able to draw conclusions from it. Here we find the dermal membrane completely matted with a dense mass of spicules, to a degree not often seen in the Spongiadas at all — still less in a sponge in which its absence is declared to be a typical character. Noting that the shaft of the birotule is longer than those described, and I need not further detain you on this form, which concludes our Thames Spongillas. I have not, however, done with varieties ; for, having spoken of the parasitic form at Henley, I am now about to introduce to you another, which, in many respects, exceeds the rest in interest. This was discovered in a large pond, or lake, of two acres in extent, at Ditchleys, in Essex, growing upon the stems of aquatic plants at the bottom. The structure of a sponge will often depend on the base upon which it grows — certainly this is the case with the class to which the Spongilla naturally belongs. So one having a broad base will have its network regular and symmetrical ; whilst another, completely like it in other respects, but springing from a narrow axis, will appear very irregular. This is particularly seen in the example under consideration, its surface is flexuous and plumose. But, here, as in all other cases, the in- terest consists in a more intimate examination. In this, the spicules are all smooth, and, in all the parasitic forms, this seems to be the case ; but here, not only is the dermal membrane thickly fur- nished with spicules, but the interstitual membranes also have them ; they are of a more delicate character than the skeleton, though IN SPONGILLA FLUVIATILIS. 59 of the same general type. So here is another variation which has not yet appeared, for, though allying itself with that of Henley, it has still its distinction from it. The membranes are more developed and require the sustaining spicula thus provided ; but it would not be difficult to show, in other examples, a step in this direction. But the most interesting fact in connection with it is the occurrence not only of the ovaria, so well known, which are to be seen here in every stage of progress, but also of that form, which occurs so often in the silicious sponges as the reproductive organ, generally termed the gemmule.* This is the first time that I ever saw or heard of this as occurring in the freshwater sponge, and it is often found in close proximity to the ovaria. The fact, however, is suggestive of the necessity of further research into the real part these organs play in the life economy. The birotulate spicule is very long in the shaft, thus bearing analogy with that at Henley (fig. 4) . A sponge found at Hertford, of which mere fragments came to my hand through our friend, Mr. Priest, to whom I have been much indebted for specimens, appears to be of the same character as that from Ditchleys, especially as regards the occurrence of the gemmule, but it appears to want the delicate spicules of the membranes ; my specimens, however, are not sufficiently good for me to determine this with precision. I have now, then, gone through the varieties, but in my search for the typical Spongilla I applied to Mr. Fullagar, of Canterbury, a gentleman well known to us, as a correspondent, and to whose courtesy I am indebted for a specimen which he procured at Bolton Mills Pool, near that city. Being always particular as to the locality and to the conditions under which an object of natural history is found, Mr. Fullagar communicated to me, in answer to enquiry, that it grew " on the bars of the grating, which is placed in front, to prevent the weeds, &c, from going to the water-wheel. * When naturalists have not yet determined the exact offices of the several organisms, it is difficnlt to distinguish them by a name. Gemmule, seed-like vessel, spore-case, ovarium, have all been given to the well-known forms connected with reproduction in the Spongillae. I have used Dr. Bowerbank's term, which he adopted, as against the gemmule ordinarily found. To this latter Mr. Carter would apply the term ovisac ; more accurate, probably, for it is certainly no gemmule in the true sense of the term. But "ovisac" and "ovarium" are synonymous, and we cannot use both. In using here the term " gemmule " it will only be for the distinction of one object from another, not as assenting to the propriety of this term, any more than some naturalists do to that of " ovarium'* given to the seed-like vessel. 60 J. G. WALLER ON VARIATION There is always a tolerably quick current passing through." Now this statement has some value, as Mr. Carter, in his article on the Spongilla of the Exe, has hinted an opinion that the agitation of the water might be a cause for the spinous condition of the spicule. I must confess this was an idea also of mine, and I was watching to see if this rule could be borne out. Obviously it cannot, for a mill- stream is always agitated, and must be always strong in the vicinity of the wheel. So as this specimen conforms to the type Sp.jiuviatilis in general character, and having but the smooth spicule, under such conditions we are not yet in a position to declare the law which operates to produce the changes alluded to. Of all the examples of the freshwater sponge I have ever received, this was the richest in sarcode. It was the very alderman of sponges, fat to a degree, evidently enjoying life, and in full possession of that by which life is sustained. The constant flow of the mill-stream suited its constitution. Laying it out to dry in a summer's day, the olfactory nerves soon became unpleasantly admonished. I observed the blow-fly paying it assiduous attention, and in a few days it was as full of maggots as a dead dog festering in a ditch. The larvae were of two kinds — one a very common form, the other having numerous feet, and the sponge was also full of eggs. Such a phenomenon I had never seen before, and if there now could be a doubt on the animality of the sponge, this fact may come into the argument. It abounded in ovaria, often packed closely together, even in this declaring its pre-eminence. The birotulate spicules, however, were long in the shaft ; in this not conforming to the type whose exact character seems to elude my enquiry. (Fig. 5.) It is time now to generalize and draw deductions suggested by the foregoing observations. I think I have sufficiently shown that Sp.jiuviatilis is subject to considerable variation, consequent upon some law as yet unknown to us. But, from the easy manner in which the changes seem to pass through a series of gradations to a complete development of parts, I cannot but feel it contrary, not only to the interests of science, but to the facts arrayed before you, to declare any one of these a new species. The differences between the two extremes are certainly remarkable when they are brought together, and require some classification, but surely we should not want to travel to the Bombay tanks to find a name for a sponge found in an English river ; still less to baptize it with the name of a German naturalist, and that of its discoverer tacked on. IN SPONGILLA FLUVIATILIS. 61 It must have been the vicious course of custom — " That monster custom, who all sense doth eat Of habits devil," That could conduct one of our ablest naturalists to such a decision. The Spongilla of the Exe is identical in character with that of Teddington ; that of Molesey and Surbiton also conform to the same, but are more completely developed ; it is therefore impossible to allow it as a species. It is indeed a very elastic argument that allies it to Sp. Meyeni on the strength of the very slightly developed spination of the spicule, and Mr. Carter does not admit the larger size of the latter as having any specific value, in which opinion I cordially agree. But it is as easy to take a reverse view, and say that S. Meyeni is allied to Sp. jluviatilis, and only a variety from it, and a far more natural conclusion. In fact, it is clear that this Spongilla may be divided into two natural divisions : one having the spicule smooth, the other spinous. Calling the first by its simple title, and the latter variety, in all its developments, with the addition of " spinosa" or " spinifera" and the demands of science would surely be better met. And, as regards the other variations, which I have noticed in both, the letters A, B, C, &c, would serve every purpose. Even in doing this one must not forget that the Tedding- ton sponge gives us evidence of the spination being but a develop- ment from the smooth spicule, so that the idea of a new species, instead of a variety, is out of the question on that evidence alone. The main point in the classification I would propose, is to retain as a general term Sp. ftuviatilis, for we may call that a known quantity whilst those of Meyeni and Parfitti are unknown. Before we can understand them we must go back to the details of our typical forms familiar in books on microscopy, if not from actual examples in our cabinets. The specific terms fluviatilis and lacustris might easily be improved upon, but the names are widely established. Sp. birotalis for the one, and Sp. ramosa for the other — the latter being indeed its old name would be more expressive of their characteristics, and would help us to class the numerous variations, British and foreign, better together. But I am indifferent on that point, so that we can avoid making unnecessary species. Against this we ought to make a stand. Natural history is no longer a study con- fined to a few of scientific leisure : it is now the healthful mental recreation of a large number of the community, embracing those F 62 J. G. WALLER ON SPONGILLA FLUVIATILIS. engaged in every department of life. It is therefore the more neces- sary that obstacles to the study of a particular branch should not be raised up by the creation of unmeaning names and complicated terminologies. Description of Plate V. The following figures of the spicules from the several specimens of the Spongilla Fluviatilis all drawn to the same scale, exceptiug the birotulate forms (40 diam.), for the sake of easy comparison, illustrate the argument of variation as against separation into species. Fig. 1 is a group from the Teddington Lock example. Fig. 2, Molesey. Fig. 3, Surbiton. Fig. 4 is a group from that of Ditchleys, the finer and more slender spicules being from the membranes. Fig. 5, from Bolton Mills Pool, Canterbury, gives the single form of acerate spicule, which characterises the species, and is remarkable for its large size, exceeding that of Sp. Meyeni, which is given in fig. 6, and which but slightly exceeds that of the longest from Ditchleys. The variation from the simple acerate to the fusiform, is here also shown, as well as that of size, which differs in every example ; those of Molesey being the smallest, the spinous one from Teddington excepted. As to the birotulate spicules, they are drawn simply as they exhibit themselves under the same magnification (440 diam) and plane, as they vary much in appearance according to focussing. But the general character is obviously the same throughout, and if they differ from those published hitherto, as regards the flat face of the rotule, it will be a question as to how far imagination has not assisted in a rather difficult task, and led draughtsmen into seeing too much. The dentate edges differ in plane, and consequently differ according as they are focussed. The figures given are such as the several examples have exhibited when the front of the rotule is shown ; and between them all, including even Spongilla JJeyeni, there is no difference except in size. In figs. 1, 2, 3, the size is precisely the same, and agrees with Sp. Parfitti. The irregularly dentate character generally prevails, but the deep, neat, and more regular dentation given to that of Teddington, is but an instance due to focussing, and can be seen in the two following examples. The large size of the birotule of Sp. Meyeni, in its long diameter, exceeds all others, but it fluctuates into smaller forms, some of which are less than that of Bolton Mills Pool, whilst the diameter of the rotule is nearly of the same size, and the birotule of Ditchleys stands as intermediate between the less and the larger, and is paralleled by that of Henley. The dentation is sometimes strongly pronounced, and in others feebly out of examples from the same sponge, and varies much in detail, preserving, however, the same general charac- teristics. Fig. 7 is the gemmule (?) or ovisac found in the Ditchley and Hertford Spongilla (125 diam.) 63 PROCEEDINGS. January 11th, 1878. — Conversational Meeting. The following objects were exhibited : — Hypersthene ... Pinnule of Nephrolepis auberosa Moss copper, &c. Hairs of Croton elutheria ... Tetanocera aratoria; Marsh fly Leaf of Salisburia adiantifolia Dendrospongia Steerii Tourmaline Eock, showing dichroism Section of testicle of kitten Protococcus ... Plumularia setacea ... Spicules of Lataria hemispheric/, ... Halyphysema Tumanoiuiczii Eucratia chelata Section of Oolite Platino-cyanide of Magnesium Mr. T. Charters White gave a very full mounting in Canada balsam. Attendance — Members, Mr. F. W. Andrew. Mr. T. H. Buffham. Mr. F. Coles. Mr, T. Curties. Mr. F. Enock. Mr. W. H. Gilburt. Mr. G. Green. Mr. M. Hawkins Johnson. Mr. J. Locke. Mr. A. Martinelli. Mr. A. D. Michael. Mr. W. Moginie. Mr. B. W. Priest. Q.M.C. Microscope. Mr. W. S. Smith. Mr. J. Woollett. description of the best methods of 63; Visitors, 11. January 25th, 1878. — Ordinary Meeting. Henry Lee, Esq., F.L.S., &c, President, in the Chair. The minutes of the preceding meeting were read and confirmed. The following gentlemen were balloted for and duly elected members of the Club : Mr. John Allinson, Mr. George H. Beaman, Mr. David Bogue, Mr. D. H. Harrison, Mr. H. B. Lindsay, Mr. B. A. Potts, and Mr. Eobert Yates. The following donations to the Club were announced : — " The Popular Science Beview " ... ... from the Publisher. " Science Gossip "' ... ... ... ... „ , " Proceedings of the Royal Society, No. 184 „ Society. " Proceedings of the Bristol Natural His-" tory Society" "I 64 " Proceedings of the Botanical Society of) £ ,-, . , ° r from the Society. Glasgow "... ... ... ... ) " Proceedings of the Belgian Microscop-") ical Society " ... ... ... ) " Proceedings of the Koyal Society of New") South Wales" j "The American Naturalist" ... in exchange. " The American Journal of Microscopy'' ... ,, „ "The Quarterly Journal of Microscopical) , , „ r D 7 Purchase. Science ... ... ... ... ) "The Analyst" From the Publisher. Ehrenberg's " Deep Sea Foraminifera and") , , nii..» [ h y Purchase. Polycystma" ... ... ... ) " The Medical Examiner " (weekly) From the Publisher. Say's " American Entomology " ... ... ,, Mr. Lee. Specimens of Diatomaceous Earth fronO ,, Rev. J. J. Halley, Yarra Biver... ... ... ... j of Williamstown. 1 Slide... „ Mr. Priest. 1 Slide... „ Mr. H. R. Gregory. Photographs for the album from Mr. Wm. Atkinson and Mr. E. T. Newton. The thanks of the meeting were unanimously voted to the donors. Mr. Ingpen called attention to a new shade for a microscope lamp, exhi- bited by Mr Swift, consisting of an earthenware cylinder surrounding the glass chimney, and having a flap shade over the aperture in the side through which the light reached the mirror. The earthenware was dark-coloured outside and white inside, and the shade was an advantage in affording an additional screen to the eyes. Mr. Ingpen, however, took objection to the cylinder being white inside; he considered black much better as avoiding glare. Mr. Ingpen also referred to a specimen of Diatomaceous earth presented by the Bev. J. J. Halley, of Williamstown, Victoria. This was discovered in cutting a drain through low-lying lands near the mouth of the river Yarra. It was very interesting to obtain contributions from distant countries, espe- cially when sent by residents. Slides of this deposit would be prepared for the cabinet of the Club. The forms were similar to the well-known " Yarra- Yarra " earth, and included several interesting species. Mr. A. D. Michael briefly described a specimen of Glyciphagus palmifer, exhibited in the room, and to which some interest attached from the fact of its having recently been found for the first time in this country. The thanks of the meeting were voted to Mr. Michael for his communica- tion. Mr. T. C. White read a paper " On Insect Dissection," in which he des- cribed the best methods of manipulation, and gave numerous hints as to the apparatus best suited to the purpose, together with some suggestions as to mounting and examination. Mr. Ingpen said they must all feel much indebted to Mr. White for his pateresting paper, which was upon a subject which he had long wanted to 65 Bee brought before the Club, and upon which many of the members would be very glad to get some information. The first part of the paper men- tioned dissecting under the microscope with an erector. Now the ordinary form of erector was excellent as applied to a telescope, but under a micro- scope it was simply abominable. There were, however, various kinds of erectors, and one which had been shown by Professor Abbe, made by Zeiss, was about the best he had seen. It consisted merely of a single achromatic combination of about two inches focus, with a stop placed above it, and it gave a beautiful definition. If they took an achromatic doublet and put it into a tube with a smallish aperture above it, and in its solar focus, and then placed it in the tube of the microscope, they would find it would prove a far finer erecting glass than those generally used. Mr. E. T. Newton said that some time since he had the advantage of speaking to Mr. Loy upon this subject, and, particularly upon the best methods of holding very small insects ; that gentleman suggested a very admirable plan, which consisted in taking an ordinary lead pencil, and stick- ing a piece of shoemaker's wax on the end of it, to which the insect was caused to adhere. He could in this manner manipulate a flea, and by remov- ing first the integument, and then putting the insect into water, the various parts would begin to swell out in such a way that dissection was greatly facilitated. Whilst admitting the great value of dissection as a means of understanding insect anatomy, he wished to call attention to the great value also of sections, which often gave information as to the relative connection of the various parts which could not be otherwise obtained, and although they were not, perhaps, of much use in such cases as that of the alimentary canal, they were of the greatest value in forming a clear idea of other parts, such as the head. Mr. Newton then proceeded to show, by means of draw- ings upon the black-board, certain particulars of the highest interest and importance, which had been made out by means of sections of the heads of Ants and Wasps. Mr. T. C. White said that he had felt at first inclined to apologise for the poverty of his paper, but certainly should not now do so, seeing that it had been the means of bringing out the very interesting remarks which they had just heard from Mr. Newton. His object in bringing the matter forward was to try and incite others to the study of the comparative anatomy of insects. Cutting sections successfully was, however, a matter which required a delicacy and manipulative skill which '* only a Newton'' could command! With regard to an erecting glass, he was fully aware of its many disadvan- tages when used with instruments of ordinary construction, particularly as the instruments had to be used for dissecting purposes when in the upright position ; if he could afford a Stephenson's binocular, of course it would be more comfortable. One more hint he would give, and that was if they wished to dissect insects in the morning, tbey should not, for the sake of steady hauds, smoke too much at night. The thanks of the meeting were unanimously voted to Mr White for his paper. Announcements of meetings for the ensuing month were then made, and G6 the proceedings terminated by a conversazione, at which the following objects were exhibited : — Blade of Oat, stained Lophopus crystallinus Diatomacese, from. Penang ... Tenthredo ductus Sections of Brazil Nut Longitudinal Section of leg of Human Foetus Cuticle of Sea Buckthorn Section of Liver of Kitten ... Glyciphagus palmifer Pappus from Rhodanthe maculata... Section of Eucalyptus globulus Mr. T. H. Buffham. Mr. W. G. Cocks, Mr. A. L. Corbett. Mr. F. Enock. Mr. W. H. Gilburt. Mr. J. J. Hunter. Mr. C. Le Pelley. Mr. Jno. Locke. Mr. A. D. Michael. Mr. T. S. Morten. Mr. F. H. Ward. Attendance — Members, 81 ; Visitors, 11. February 8th, 1878. — Conversational Meeting. The following objects were exhibited : — Skin of Haddock, showing pigment cells ... Hairs of Alyssum montanum Tegenaria atrica Ovipositor, &c, of Gadfly Fructification of DicTcsonia antarctica Section of stem of fig Head of earwig Section of Human Mammary gland Granite, enclosing Mica schist Muscular fibre Medusiform gonozoid of Obelia geniculate Stictodiscus Bury anus Gneiss, from Fribourg Syenite, from Upsala Various absorption spectra, under Hilger's Mr. F. W. Andrew. Mr. C. G. Dunning. Mr. F. Enock, Rev. H. J. Fase. Mr. W. H. Gilburt. Mr. H. G. Glasspoole. Mr. A. H. Halley. Mr. J. J. Hunter. Mr. M. H. Johnson. Mr. A. Martinelli. Mr. A. D. Michael. Mr. W. Moginie. Mr. G. J. Smith. >> >» 1 Mr. F. H. Ward. Spectroscope Mr. Ingpen continued his demonstration of the principles of the Achro- matic Microscope. Attendance — Members, 54 ; Visitors, 7. February 22nd, 1878. — Ordinary Meeting. Henry Lee, Esq., F.L.S., &c, President, in the Chair. The minutes of the preceding meeting were read and confirmed. Mr. Eobert M. C. James and Mr. Samuel H. Needham were balloted for and duly elected Members of the Club. The following donations were announced : — " Science Gossip " from the Publisher. " The Medical Examiner " „ „ 67 « Proceedings of the Belgian Microscopical") frQm fche Societj- Society" ... ... ••• ... ) "The Octopus," by Mr. Henry Lee ... „ the Author. " Thudichuni's Manual of Chemical Phy-~) Mr jTeeman. siology'' ... ... ) " Brongniart's Mineralogy " „ Mr. M. H.Johnson. " Annals of Natural History '' by purchase. 1 Slide (Glyciphagus palmifer) from Mr. Michael. 12 Slides (Foraminifera) „ Mr. Hailes. 1 Slide (Diatoms, from Yarra Eiver) ... „ Mr. Priest. 1 Slide (Diatoms from Yarra Eiver) selected") Mr< rpoppino'. and aranged... ... ... ... ) A series of Slides of parasites of the Rat,") w f Mr. Beulah Babbit, &c ) |per Mr. T. Curties. Photographs of the Eev. W. M. Hutton, the Rev. W. Quekett, and Mr J. R. Eddy, were presented to the album. The thanks of the meeting were unanimously voted to the donors. Mr. Ingpen said it might be useful to some members to know that ground glass slides could be obtained with a surface fine enough for microscopical use. This surface was in the condition to which plate-glass was reduced immediately before polishing, and was without any of the roughness observ- able in ordinary ground glass. The specimen which he had brought for inspection was prepared by Messrs. Chance, and he believed slides of it could be obtained at Messrs. Home and Thornthwaite's. Mr West read a paper " On Microscopic tracings of Lissajous' Curves," the subject being illustrated by specimens exhibited under microscopes in the room ; also by larger figures of the same kiud, drawn upon smoked glass, and a number of the well-known curves produced by Mr Tisley's machine. Mr Ingpen read a letter from Mr. Wm. Webb, whose skill in microscopic writing and ruling was known to most microscopists, highly praising Mr. West's beautiful productions. Mr. Webb s opinion upon the sub- ject was entitled to great weight from the great beauty of his own pro- ductions, and his known skill in fine writing and ruling. Mr. West had not referred to the value as test objects of some of these figures, in res- pect of the possibility of measuring the lines of which they were composed. If they had any figure in which the lines were more or less elliptical, they might probably be so drawn that a band should be produced, showing wide lines at the top of the ellipse, whilst the same number would be drawn very much closer together towards the middle of the figure. In this way they might obtain a series of bands of known number and character, and yet so close as to be a very fair test for an objective. He thought that this was a point at which these slides ceased to be mere toys. The difficulty hud been mentioned as to the right kind of illumination to be used in examining these very delicate figures, and he thought it would be a severe test to put one of these slides before an amateur and ask him to show it properly. Mr Curties said he had great pleasure in assisting Mr. West in the illumi- 68 nation of these objects, and they had certainly turned out better than he had expected. He thought the best results had been obtained by a spot lens, thrown somewhat out of focus ; then the water-marking came out very beautifully ; the stereoscopic effect also was very remarkable. Dr. Matthews said he conld testify to the extreme beauty of these curves, and also to the stereoscopic effect, which seemed to be due to some illusion. These figures appeared to him to throw some light upon the subject treated of by Mr. Sorby, in one of his addresses, as to the ultimate limit of vision, for, as the lines approached one part of the curve, they became so close that it would be impossible to estimate their value unless their number had been previously known. Mr. Ingpen said he should like to ask Mr. West what kind of diamond point was used in drawing these figures, and also how it happened that the crossings of the lines, though so fine, showed no signs of splitting. Mr. West could only say that he thought he had been rather fortunate in fixing the diamond in a good position ; the point seemed to be rather blunt, and, in shape, like that of a minie bullet. Mr. Ingpen enquired what kind of glass was used ? Mr. West said he had used the ordinary microscope slips. He believed these were made of two sorts of glass, some being patent plate and others flatted crown. His chief difficulty had been with the surface of the glass. He did not think that the glass used for ruling micrometeis would answer so well. Mr. Powell, in reply to a question from Mr. Ingpen, said that the glass used for micrometers was the ordinary thin covering glass. Mr. Curties said there was a great difference between the cuts in the case of a micrometer line and the lines drawn by Mr. West ; in the latter the point seemed rather to slide along the surface than to scratch into it. Dr. Matthews said that, according to what he had seen of these lines, they seemed to be more like shallow cuts than scratches, in which there had been a removal of surface, so that if this were the case he should hardly expect any dust to be produced. Every one who had made use of a glazier's diamond was aware that there were two kinds of marks which could be made with it, one being a true cut, and the other a scratch. Mr. Spencer said that whenever a cut was made there was no dust pro- duced. Dust only was made when the attempt to cut was a failure. He had often tried to get a cut with the black diamonds, but could never succeed. The true cut was something physical and molecular, rather than mechanical. Mr. Ingpen said they must have a natural crystal of diamond to cut with ; a point of a broken surface would be of little use. Dr. Matthews remarked that in the new steel roller for cutting glass the curves of the edge were much the same as in the cutting diamond, and the same effect on the gla^s was produced. There was no cut through but it caused some kind of molecular disturbance. Mr. West said that he had found dust in the course of his experiments, but he had not examined it. He had also tried to fill in the lines, but had not yet been successful with either lamp-black and oil, carmine, or aniline; he 69 had not yet tried a fine kind of graphite, which he was told might, perhaps answer better. The President proposed a vote of thanks to Mr. West for his interesting paper, which was carried unanimously. Notice was given that ac the next gossip night Mr. Newton would explain the process of cutting soft tissues, and that at the next ordinary meeting there would be a paper read "Ona New Micrometer," by Mr. Burch. The proceedings then terminated with a conversazione, at which the follow- ing objects were exhibited : — Specimen of Gabbio (Polarized) Fungi on cover of an old book Fossil Fern Spores, &c, from Lancashire lower coal measures Obisium orthodactylum (unpressed)... Common house Gnat Wing of house Cricket Stamens of Deutzia gracilis Palate of Trochus lineatus ... Spiral fibre of seed coat of Collomia Scrapings from Atlantic Cable, 880 fathoms Sections of Human Teeth ... Hair of Indian Bat ... Specimens of ruled curves on Glass, in" illustration of his paper... Attendance — Members, 74; Visitors, 7. Mr. F. W. Andrew. Mr. Batchelor. Mr. T. H. Buffham. Mr. F. Enock. Rev. H. J. Fase. Mr. A. H. Halley. Mr. Martinelb. Mr. Moginie. Mr. J. W. Reid. Mr. F. Reeve. Mr. Topping. Mr. Woollett. Mr. West. March 8th, 1878. — Conversational Meeting. The following objects were exhibited : — Tongue of Mouse, injected ... ... A Blade of Grass, stained ... Geophiluslongicomis (Snake centipede) Leaf of Dendro -calamus giganteus, stained Aulacodiscus Kittonii ... Mr. F. W. Andrew. Mr. T. H. Buffham. Mr. F. Enock. Mr. W. H. Gilburt. Mr. H. G. Glasspoole. ; 1 Bladder of Guinea-pig, injected, showing" Peyers glands Graphic Granite from Portsoy Foraminifera from Indian Ocean Soundings Cynoglossum sylvatica Section of Human Skin Graphic Granite from Scotland Ptyclwdus tooth from chalk... ... ... ,, ,, Mr. E. T. Newton gave a detailed explanation of the method of preparing and cutting sections of soft tissues. Attendance — Members, 71 ; Visitors, 5. Mr. J. J. Hunter. Mr. M. H. Johnson. Mr. B. W. Priest. Mr. J. W. Reid. Mr. G. J. Smith. 70 March 22nd, 1878. — Ordinary Meeting. Dr. J. Matthews, F.R.M.S., Vice-President, in the Chair. The minutes of the preceding meeting were read and confirmed. The following gentlemen were balloted for and duly elected members of the Club : — The Ven. Archdeacon Darby and Mr. E. Darke. The following Donations to the Club were announced : — "The Journal of the Eoyal Microscopical") „ _, . _,.,„ > from the Society. Society" ) J " The American Journal of Microscopy "... ,, the Publisher. " Science Gossip " ... ... ... ... ,, „ " Annual Eeport of the Geologists' Asso the Association, ciation ■} > „ the Society. " Proceedings of the Belgian Microsco- . pical Society " "The Analyst" , the Publisher. " The Medical Examiner " (weekly) ... „ ,, " Eeprint of a Paper on Melicerta " ... „ Mr. F. A. Bedwell. " The American Naturalist " ... ... in exchange. "Annals of Natui'al History'' ... ...by purchase. Six Specimens of " Solid'' Insect Mounting... from Mr. Curties. Two Slides • ... ... ... ... ... „ Mr. Glasspoole. Seven Slides of Polyzoa ... ... ... „ Mr. Michael. Twenty-two Slides of Sections ... ... ,, Mr. Newton. The thanks of the meeting were unanimously voted to the Donors. The Secretary exhibited and described a new form of air pump for microscopical mounting purposes, devised by Mr. Edmund Gardner, and carried out by Mr. Browning. Two patterns of the instrument were shown, the simpler of which consisted of a glass tube cemented to the exhausting syringe at one end, and closed at the other by a screw cap rendered air tight by means of an india-rubber washer. The slide to be operated upon was placed in the tube, and the effect produced by the exhaustion of the air could be readily observed. A more elaborate form of the apparatus was also placed upon the table. The Chairman said that the great difficulty with regard to the ordinary form of air pump was in keeping the receiver air tight, but by the use of vulcanised rubber, the vacuum in the little instrument before them could be easily maintained. Mr. Thos. Spencer enquired if anything was known as to the cost of these instruments ? The Secretary had not been informed, but he believed it would be certainly less than that of most of the usual forms, on account of its extremely simple character. A paper by Mr George J. Burch, of Cheshunt College, "On a New Micrometer," was read by Mr. Curties, the subject being illustrated by diagrams, and by the exhibition of several forms of the apparatus described. Mr. Curties, at the conclusion of the paper, expressed his inten- 71 tion of making a model from the design of Mr. Burch, and of presenting the same to the Club. The Chairman said that this very clever invention was calculated to promote what every microscopist should do, namely, draw everything to scale. It appeared to be an ingenious attempt to make one eye do what had formerly been done by both. He had much pleasure in moving a vote of thanks to Mr. Curties for reading the paper, and would beg him to convey the thanks of the Club to the gentleman who had been at the trouble of elaborating it. Mr. Ingpen said that he had an interesting paper to read by Mr. Stani- forth Green " On Insect Mounting." Mr. Green had x-esided some years in Ceylon, and made good use of the opportunities there afforded to him of collecting and mounting insects. He was one of the first to mount them in the solid, and to protest against the ordinary method of compressing them, and he now gave them his process of mounting and preserving. The paper was then read to the meeting. Mr. Thomas Spencer wanted to know what the Anti-Vivisectionists would say to the paper, because the insect must, of course, be killed before they commenced to operate, and it was probably killed rapidly by the action of the turpentine. Mr. Ingpen said that most insects were killed instantaneously by placing them, in turpentine ; one of the quickest means of killing them was by plunging them into boiling water. The Chairman could assure Mr. Spencer that turpentine was an un- doubted anaesthetic, and therefore no doubt these insects died happily. He had often prescribed turpentine to patients to be used as an outward appli- cation, and had ascribed its beneficial effect not so much to its action as a counter irritant as to its anaesthetic effect upon the patient. Mr. Spencer said he had no doubt that death was quick, and what they might call instantaneous ; but what might be to a human being only half a second of time might be half a minute to the insects. However, he only spoke of the matter philosophically. Dr. Matthews was very glad the subject of mounting insects in their natural condition was receiving attention ; he himself had been almost one of the first to protest against the process of squashing them. Mr. Ingpen thought it important that they should get all the informa- tion they could on the subject, especially with regard to getting specimens from foreign parts with the least amount of injury. The extremely beautiful manner in which objects mounted by Mr. Green's plan were shown by the paraboloid, the perfect condition of the trachea, eyes, and muscular tissue, rendered this process a matter of the greatest interest. A vote of thanks to Mr. Staniforth Green was unanimously carried. Announcements of meetings and excursions for the ensuing month were then made, and the proceedings terminated with a conversazione, at which the following objects were exhibited: — Tongue of Honey Bee Mr. F. W. Andrew. Shell of Haliotis sjplendens Mr. A. L. Corbett. 72 Micro-photograph of Professor Queketfc , Spinnerets of Garden Spider (nnpressed) Growing Point of Equisetum Section of Hedge Maple Scale of Haddock Section of S acker of Octopus Scale of Lepisma Stellate Hairs of Deutzia Crystals from Opium liniment Section of marble Attendance — Members, 80 ; Mr. T. Cnrties. Mr. Enock. Mr. W. H. Gilbnrt. Mr. Glasspoole. Mr. Goodwin. Mr. J. J. Hunter. Mr. J. Locke. Mr. Martinelli. Mr. T. H. Powell. ... Mr: W. S. Smith. Visitors, 8. April 12th, 1878. — Conversational Meeting. The following objects were exhibited : — Young Salmon Trout... Head of Hyous papillosa, Tongue of Sphinx Moth Red Snow — Protococcus nivalis Eggs of Vapourer Moth Section of Chalcedony Diptera ... Knee-joint of Human Foetus Chert from Axmouth... Hydractina Gemellaria coricata ... Polyzoa ... ... ... ... Yeast Plant Mr. W. H. Gilburt gave an interesting description of the method of bleaching and staining vegetable tissues. Attendance — Members, 68 ; Visitors, 5. Mr. F. W. Andrew. Mr. Dunning. Mr. Enock. Mr. H. G. Glasspoole Mr. W. Goodwin. Mr. G. Green. Mr. A. H. Halley. Mr. J. J. Hunter. Mr. M. Hawkins Johnson. Mr. A. D. Michael. Mr. T. S. Morten. Mr. Ogilvy. Mr. A. C. Tanquery. April 26th, 1878. — Ordinary Meeting. Henry Lee, Esq., F.L.S., &c, President, in the Chair. The minutes of the preceding meeting wei'e read and confirmed. Mr. George W. Gibbins was balloted for and duly elected a member of the Club. The following donations to the Club were announced : — " Proceedings of the Royal Society" (two) „ ,, _, . " & J i from tlie Society, parts)... ... ... ... ... ) " The Popular Science Review " ... ... „ the Publishers. "The American Journal of Microscopy" ... in exchange. "The Annals of Natural History "... ... by purchase. " Report of the Croydon Microscopi Club" opicaH from the Club. 73 The Quarterly Journal of Microscopical) ~ . "" „ > by purchase. Science ... ... ... ••• ) Report of the Microscopical Society of) . Liverpool "... ... ... • • • J Liverpool " " Science Gossip " )? the Publisher. in exchange, from Mr. F. Crisp. „ Mr. Tatem. „ Mr. Glasspoole. " The American Naturalist "... " Harting's Treatise on the Microscope " Six Slides of Desmids One Slide — Red Snow Photograph of Dr. Matthews, for the Club album. The thanks of the meeting were unanimously voted to the Donors. The President said that Dr. M. C. Cooke had laid before the committee a plan which had received their cordial approval, and which he would ask that gentleman to explain to the meeting. Dr. M. C. Cooke said that having found a certain plan which he had adopted for years of considerable use to himself and friends, he had thought that the larger association of friends who formed the Club might gain some advantage from it also, if he showed them how it might be carried out. They all knew that he attached great value to drawings made from objects under observation — in the progress of years names might be changed, and organisms might be placed in other classes where it would be difficult to recognise them, but a faithful drawing was always of value- When Ehrenberg had only a £5 microscope to work with he made drawings of what he saw, which were now regarded as of great value, although his descriptions were, many of them, become out of date. In studying fungi he had made a practice of obtaining drawings from all sources, and of every species which it was possible to obtain, and he had collected alto- gether about twenty thousand such drawings of fungi, mounted in uniform size and kept in portfolios for easy reference ; and he had thought that this plan would be of value in the Club, and might be of special use at their gossip nights. Say the subject illustrated was that of Algce, for instance — any one being interested in the subject, and desirous of identifying any specimens, might come to the Club on a gossip night, and having looked over a box containing figures of Algce would probably be able to obtain the information he required. The committee approving of the suggestion, had authorised the purchase of paper of the size found most convenient, and ruled for the purpose ; any one who had any drawings at disposal, and was willing to give them for the purpose, might obtain some of this paper upon which the drawings were to be mounted. The mounting would, of course, have to be done by the member presenting the drawings, because it would not be fair to ask any honorary officer of the Club to undertake this trouble. Care should be taken to mount illustrations of one species only on a single sheet, because the sheets were intended to be kept like a pack of cards, so as to be sorted and arranged as easily as possible; where drawings were taken from books, or where engravings were mounted, members should in all cases state the work from which the extracts were made ; and when original drawings w T ere contributed, the name of the con- 74 tributor should always be given. These suggestions, if carried out, would add very greatly to the value of the specimens. The President said he need not add that the suggestions made by Dr. Cooke met with his hearty approval, and that the committee had decided to purchase a ream of paper the same size as that of the specimens brought to the meeting by Dr. Cooke. He should be very glad to see this new movement encouraged. Mr. J. G. Waller read a paper " On Variation in Spongilla fluviatilis," the subject being illustrated by diagrams showing the close resemblance of several so-called species. The President, in inviting observations upon the paper, said that he so far agreed with what Mr. Waller said, that when some years ago he had a specimen of Spongilla Meyena sent to him by Dr. Bowerbank, he wrote to ask him if he had not made a mistake and sent S. fluviatilis instead, for he could not see any difference. Having called attention to a specimen brought by the late Mr. J. K. Lord from Vancouver's Island, he enquired if Mr. Waller held that there was a specific difference between S. fluviatilis and 8. lacustris, Mr Waller said he quite believed these to be different, although he had shown that they had been found growing together in the same locality. Dr. Matthews asked if the so-called species did not depend upon such things as food, temperature, and the mineral constituents held in the water ? He thought these might be possible causes of the variations, and he was inclined to lay great stress upon the quantity of silex contained in the water. He added his protest to that of Mr. Waller against the terrible multiplication of species. Votes of thanks to Dr. M. C. Cooke and Mr. Waller for their communica- tions were then proposed by the President, and carried unanimously. Announcements of meetings and excursions for the ensuing month were then made, and the proceedings terminated with a conversazione, at which the following objects were exhibited: — Cuticle of Ficus elastica, showing stomata Section of Echinus Spine Plumose Antennae of Biston hirtaria English Tingis (?) Section of Epidermis of Rat " Daphnia pulex y Flour Mites Micrasterias tlenticulata (mounted) ... Volvox globator ditto Young Sea Anemones ... ... ... Salivary Glands of Kitten (injected) G lycip h agus spinipes ... 33 Sectious of the head of one Blattal orientalis ... ... ... ... j Phlogopite — a variety of Mica I Mr. F. W. Andrew. Mr. A. L. Corbett. Mr. F. Enock. Mr. H. E. Freeman. Mr. W. H. Gilburt. Mr. Goodwin. Mr. H. E. Gregory. Mr. H. F. Hailes. Mr. A. H. Halley. Mr. J. J. Hunter. Mr. A. D. Michael. Mr. E. T. Newton. Mr. J. Woollett. Attendance — Members, 83 ; Visitors, 5. 75 On an Apparatus for Facilitating the Use of " Powell's Small Bull's-eye" Illuminator in the Resolution of Test Objects. By Geo. Williams. (Read May 24, 1878J Plate VI. The attention of microscopists having lately been much devoted to the determination of the merits of object-glasses of recent manu- facture, and to the more or less successful exhibition of beads, lines and stria? on diatoms and other objects, especially with reference to the several condensers and other optical means and appliances by which the desired results can be best obtained, I have thought that a short paper bearing upon the latter portion of the subject might be interesting ; and I beg leave to introduce to the meeting, this even- ing, a contrivance of mine which I have designated " An Apparatus for Facilitating the Use of ' Powell's small Bull's-eye ' Illuminator in the Resolution of Test Objects." A very simple, but at the same time highly effective, method of resolving the transverse strice or ribs of Amphipleura pellucida is that employed, and first devised, as I believe, by Messrs. Powell and Lealand. It consists in concentrating an intense beam of light upon the frustule, at a very extreme angle, by means of a small il bull's- eye " of very short focus. For this purpose a super-stage is re- quired, which may be briefly described as a thin platform, slightly larger than an ordinary 3x1 slip, raised upon uprights about an inch above the level of the princij)al stage, the base bearing the up- rights sliding on upon the dovetails which take the upper stage- plate, that having been first removed. The platform, thus fixed, assumes a position perpendicular to the body of the microscope, and has a £" central opening, horseshoe-form, cut out from its side edge to about \ rds of its width ; the light, therefore, on one side of the platform, meets with no obstruction. The slip being laid upon the G 7G G. WILLIAMS ON THE USE OF platform beneath its springs, the flat side of the "bull's-eye" is brought close up to the side edge of the slip, a brilliant beam is concentrated upon, and thrown across, the slide, the proper illumina- tion is obtained by the necessary manipulation, and the markings are thus resolved. In order, however, to show these transverse lines or striae with this "bull's-eye," it is necessary that they lie at right angles to the direction of the light. A selected slide, prepared on purpose, of course provides for this, the mounter arranging the frustules on the cover, and fixing it so that they lie across the slip ; but, to say nothing of the great difficulty of thus arranging A.pellucida (which high skill and much patience can alone accomplish), the number of the valves is generally limited to some half-dozen, and these few mostly turn out to be so extremely difficult of resolution, and are otherwise so unsatisfactory as to render the slide of comparatively little use. A good ordinary strewed slide, on the contrary, contains hundreds of the valves, and amongst them may be found, by diligence, many on which the lines can be seen with reasonable ease ; but it is obvious that the "bull's-eye" can be made to successfully operate upon those specimens only which happen to lie in the direction of the width of the slip, or within very narrow limits thereof ; the rest of the specimens, and possibly the best, being incapable even of examination owing to their unsuitable position. To place any one of the latter in the right direction it is clear that the only course is to turn the slide by the rotating motion of the microscope ; but the length of the slip quickly interferes with, and pushes aside, the " bull's-eye," and there is nothing for it but to abandon the examina- tion of that valve. To overcome this difficulty, and put an end to the annoyance of seeing crowds of frustules which one cannot even attempt to resolve, I have devised the easily-made and inexpensive apparatus described below ; and I have ventured to bring it to the notice of the members of the club, in the hope that it may meet with approbation, and extend the use of this excellent illuminator, which will be found to give very good results with A. pellucida, and to be equally effective in resolving other tests ; always, of course, assuming that an objective be employed which is competent to the task. Fig. 1 is a disc of thin plate, or crown, glass, f " diameter, on which may be mounted diatoms in balsam, or dry strewed on the cover. Any cover carrying dry diatoms can be easily removed from Powell's small bull's-eye illuminator. 77 its slip, transferred to the disc, and cemented thereon, as shown in the figure. A rough edge to the disc greatly facilitates its handling. Fig. 2 is a tubular setting or holder, 1" long and f" diameter inside measure ; the top cut out so as to leave 3 equidistant \ " uprights, having small lips upon which the disc (fig. 1) is to rest. The tips of the uprights are slightly inclined inwards to spring lightly against, and steady, the disc, to overcome the suction of an immersion objective. The uprights should be as slender as possible, consistent with the needful strength, that as little obstruction as may be shall be presented to the passage of the light beneath the disc. Fig. 3 is a brass plate 3" by 1", having a tube -§-" long fixed into central hole. The tube to well fit fig. 2, the latter resting on the flange, and rotating easily and smoothly, but without any " shake." The small milled heads screw the plate to the principal stage of the microscope (two holes being tapped in the stage-plate to receive them) , that the disc may be subject to the concentric rotating and other mechanical motions ; so that the whole mount may be brought suc- cessively under the objective. A ny other mode of firmly fixing the plate to stage may be substituted for the milled heads, which are suggested merely as an easy but secure method of fastening. Fig. 4 is a brass rod to support the " bull's-eye " — a plano-convex lens of about %' diameter and ^" focus. The rod is furnished with ball and socket joint (to give universal motion), to be inserted in the usual fitting in the head of the carrier (Ross model), or in the crane arm (Jackson model). The rod is curved to advance the "bull's- eye" approximately into position, which is afterwards brought close to the disc by the ball and socket joint. The shape of the curve will depend upon the form of the microscope to which the rod may be fitted. The cell of the "bull's-eye" is attached to the rod by a tongue-joint that it may be "kept square" whatever the inclination of the rod. The rod must be sufficiently long to allow the "bull's- eye" to be conveniently manipulated ; it is divided in the figure to show the necessary milled stud at the tail-end. The pin of the joint should fit into a square hole, thus confining all motion to the joint itself, and preventing any tendency to " crawl." The socket should be carefully packed to obviate all jumping motion in the joint, the ball moving freely. Fig. 5 is a brass plate, 3" by 1|", with central aperture f " diameter, turned out so as to leave a very thin and narrow flange, as shaded in the figure. This aperture is to receive and support 78 G. WILLIAMS ON THE USE OF POWELL'S ILLUMINATOR. the disc on the stage of the microscope, in case it should be desired to examine the mount as an ordinary slide by illumination from the sub-stage. The disc will require to be kept steady by a slight spring ring to counteract the suction of the immersion objective. It will, I think, be seen that by mounting the diatoms on a small disc instead of the ordinary slip, and placing it in the holder above described, the whole of the frustules on the cover are brought under the control of the observer, who, by mere rotation, can bring any one of them into the necessary position, and thus ultimately succeed in examining a large majority. Having selected a specimen, and rotated it into position, one of the uprights of the disc-holder may chance to stand immediately between the diatom and the light ; in that case, all that is necessary is to turn the disc in its setting, and again rotate the holder until the object is again in position ; a glance will show whether or not the light will now pass between the uprights, if not, the turning of the disc and rotation of the holder must be repeated until it does so. The turning of the disc and rotation of the disc-holder can be easily managed with thumb and finger, under a quarter-inch objec- tive ; indeed, with a well-made apparatus, but little difficulty has been found even under a -^th, aided by a mechanical stage in good working order. The rotation can, of course, be effected by the use of the concentric motion of the microscope stage ; but, in practice, it will be found far preferable to rotate the holder itself to approxi- mately place the object, resorting to the concentric motion to effect only the niceties of position ; the milled heads which work the mechanical stage will then retain their normal situation (or very nearly so) , at the right side of the microscope, and be, consequently, much more convenient for the manipulation of the observer. 79 On the Influence op Diffraction in Microscopic Vision. By Frank Crisp, LL.B., B.A., Sec. R.M.S., V.P.Q.M.C. {Read June 28, 1878.) Plate VII. The subj ect which I bring before you this evening is now, so far as date is concerned, somewhat of an old story, but unlike some of the other old stories of the world which are being daily repeated it is one which, I think, will peculiarly bear repetition — the discoveries of Professor Abbe, in relation to the resolution of minute structure, being as remarkable as any that have been made in ancient or modern Microscopy. I intend to deal only with the most elementary parts of the sub- ject, advisedly abstaining from attempting to present any more com- plete resume, as I am convinced that its real significance and import- ance will be far more likely to be appreciated if I confine myself to the leading points. Moreover, there will be this advantage, that I shall have left ample room for entertainment on future evenings, and every one will be able to leave to-night with the knowledge that he can occupy very many leisure hours in further investigations. I shall not, perhaps, be far wrong if I assume that there are some present who are not aware that within the last two or three years the theory of microscopic vision has received a new and important development, so that some of the old notions — which seemed to depend on the simplest principles, and not to be susceptible of innovation — have been completely exploded, leaving a feeling of not a little wonder that such simple facts had escaped observation, and that we should have had them so long, literally right under our noses, without any appreciation of their importance. It is desirable at the outset to point out the two leading ideas hitherto held, which are now known to be erroneous. The first error relates to the mode of formation of the microscopic image. It will be remembered that in our books on optics or the microscope, the images of objects are stated to be formed in that 80 F. CRISP ON THE INFLUENCE OF instrument on ordinary dioptric principles, that is, in the same way in which they are formed in the telescope or a camera, and if any microscopist were asked to describe the way in which a diatom or other lined object is seen in the microscope, it would have been in this manner that the explanation would, without hesitation, have been given. It had never been suggested, prior to Professor Abbe, that that (which may be termed the dioptric method) was at all incorrect. One result of this view was that, in the manufacture of objectives, very erroneous methods came to be adopted — methods that were perfectly correct if the images were formed dioptrically, but entirely inapplicable if that theory was unsound. The second error relates to angular aperture. Not long after achromatic object-glasses were first made, Dr. Gor- ing found that the markings on particular objects, such as the scales of the wings of insects, could not be seen by some object-glasses, while with others, of equal magnifying power, they were clearly visible. This led him to the important discovery that the resolving power (or, as he termed it, the " penetrating" power) of an objec- tive depended upon the extent of its angular aperture. One of the explanations given of the cause of this quality of the objective was that, as by the larger aperture, rays of greater obliquity were admitted, structural details became more plain, in the same way that the inequalities on a white wall or a person's face are plainer when the light falls upon them obliquely — casting shadows — than they are by direct light. This theory has remained without alteration to the present day, and some writers have exhibited the most praiseworthy efforts to account for some of the anomalies that the theory did not satisfy, much in the same way as the old astronomers who, when the motions of a planet seemed to become erratic, did not throw over the theory which they had adopted to account for the motions, but added additional crystal spheres, until at last the whole thing was so mar- vellously complicated that it is a wonder how any sane person could have believed in it. I now come to the phenomena which show that a special and important part of the functions of the microscope has been over- looked, and that both the theories just referred to, that of the dioptric formation of the image, and that of angular aperture are, in the case of lined objects, erroneous ; the explanation, in fact, DIFFRACTION IN MICROSCOPIC VISION. 81 equally applies to granular bodies, or others with minute structural details, but fine lines present the simplest phenomena, and are best suited for the present demonstration. I assume a general acquaintance with the phenomena of the inter- ference of light, and with the so-called diffraction images that are produced when a flame (for instance) is looked at through a fine grating, such as lines ruled on glass. I have, however, some grat- ings for examination after the meeting, which will make the experi- mental part of the subject, at any rate, very plain. If any, not too finely-lined, object is focussed on the stage of the microscope, and the eye-piece is removed, on looking down the tube, instead of seeing only a small circle of light, we see, in addition, other subsidiary circles, or rather ovals (as shown in Figs. I, II), which, if white light is used, appear with the colours of the spec- trum, the blue being always towards the centre. The central circle is the direct image of the aperture in the dia- phragm, and, when the eye-piece is in position, gives a view of the object on an illuminated field. The ovals are the diffraction images (or " spectra ") of the open- ing, and any two of them together will give an image of the object on a dark field. They are formed by the interference of the light in consequence of its passage through the object, in the same way as the images of a flame are produced by a grating in the ordinary diffraction apparatus. In the case of the scales of insects or valves of the diatoms, the variations in their structure, whether arising from unevenness of surface, from the unequal transparency of parts of the structure, or from holes, or whatever it may be, will produce precisely the same effect upon the object as is produced by the lines ruled on glass, the light transmitted through such objects not entering the object-glass in the same direct line which it held in its course from the mirror to the object, the structure causing a number of rays to be separated from the rectilinear rays on each side — these deflected rays forming larger or smaller angles with the lines of direction of the unchanged rays, according to the greater or less minuteness of the structure. The theory propounded by Professor Abbe, as the result of his observation of these diffraction images is, that the microscopic image consists, as a general rule, of two superimposed images, each distinct in origin and character, and capable of being separated 82 F. CRISP ON THE INFLUENCE OF and examined apart from each other — one image being that by which the contour outlines of the larger parts are formed, the other image giving the delineation of minute structure. So in the case of an object with lines closer than g^oo" °^ an i ncn apart, the image seen by the eye is formed not simply by the cen- tral dioptric beam, but by the joint action of that and the diffraction images and their exact union in the upper focal plane of the objective. How important an influence the diffraction spectra haVe on the formation of the image, may be seen by the following experiments, which, for the moment, I must explain by means of diagrams, though they can be verified after the meeting under the microscope. Fig. I represents the appearance in the field of the microscope of an object formed of two sets of lines ruled through a thin film of silver deposited on glass, the lower set being twice as close as the upper ones. Fig. II shows the appearance which is presented on removing the eye-piece and looking down the tube of the microscope, the central circle in each series is the dioptric beam, the others being the diffraction spectra. It is important to observe that the distances of the spectra apart are inversely as those of the lines, the upper (widely separated) lines producing spectra twice as close as those of the lower. If we now place over the back of the object-glass a diaphragm like Fig. A, the diffraction spectra will be admitted, as well as the central beam, when the slit of the diaphragm is at right angles to the direction of the lines ; when, however, the diaphragm is turned round 90°, so that the slit is vertical, the whole of the diffraction spectra are shut out, and nothing but the dioptric beam is admitted. If, therefore, the diffraction spectra contribute, as the theory assumes they do, to the formation of the image, some change ought, of course, to be perceptible when they are thus excluded. It will be found that, as the diaphragm is turned round, and the diffraction spectra disappear, the lines also disappear, and not a trace of them can be seen (Fig. a). This demonstrates the importance of the spectra in the formation of the true image, and we may now carry the demonstration a step further, and show what influence they may have in the formation of false images. Referring again to Fig. II, if we are able by any means to make the spectra of the upper lines identical with those of the lower, it DIFFRACTION IN MICROSCOPIC VISION. 83 would be reasonable to assume, if the theory is correct, that the images of the two sets of lines, as seen by the eye through the microscope, would resemble each other. This object maybe attained by placing at the back of the object- glass the diaphragm, Fig. B. It will be seen that when this is placed over Fig. II, each alternate one of the spectra of the upper (more widely separated) lines is cut off, so that they become identical with those of the lower lines. On now replacing the eye-piece, and looking at the object in the ordinary way, the appearance shown in Fig. b will be presented, and it will be seen that the wider lines have doubled in number, and, so far as definition is concerned, have become identical with the lower lines, the only possible mode of distinguishing them being by a slight decrease in light, which is necessarily caused by the partly opaque silver film in reality existing where the false lines appear. We can carry this experiment a step farther, for better illustration of the effects produced, by again " tampering " with the spectra. If the object had consisted of lines twice as close as those of the lower set of Fig. I, the spectra would have been twice as far apart, that is, at the distance of the outermost ones of Fig. II (the space between them and the central beam being unoccupied). This state of things can be produced artificially by cutting off all but the outermost spectra by the use of the diaphragm (Fig. C), and when that is done, instead of the two sets of wide and narrow lines, or two sets of equally distant ones (as in Figs. I and b), we have the wide ones quadrupled and the others doubled in number, so that the object presents the appearance of Fig. c, and, as in the previous case, no one seeing them would hesitate to affirm that the finer lines really existed. This leads us to the application of Prof. Abbe's theory in the true explanation of angular aperture. If, in the last experiment, the lines were still closer together, the spectra, now almost at the verge of the field, would have been thrown outside it altogether, and we should have had nothing but the central beam, with the same result as first shown, viz., the entire disappearance of all lines ; in other words, the object would not be " resolved" by an object-glass that would only take in the former spectra. If, however, we had an object-glass of larger angular aperture, so that the spectra thrown outside the field of view in the former case 84: F. CRISP ON THE INFLUENCE OF were now brought within it, the lines of the object would at once become visible, and the latter object-glass would have in ordinary parlance greater " resolving power " than the former. The advantage, therefore, of an object-glass of large angle over one of smaller angle consists, in the case of objects with minute details, entirely in the fact that spectra, which with the one are thrown outside its field, are with the other brought within it, and thereby details of the object become visible. We are consequently at once able to dispose, on the clearest grounds, of the controversy, raised a year or two back, as to the power of small-angled object-glasses to show the finest lines. Those who asserted such a fact were evidently (however unconsciously) drawing upon their imagination. One other experiment may be mentioned as extending somewhat the ideas which the preceding ones enable us to form, and will be interesting to Microscopists as bearing upon the question of the structure of P. angulatum. If an object is taken which is formed of two sets of lines placed over one another at right angles, we get of course a series of squares, as shown in Fig. Ill, which produces the spectra of Fig. IV. It must be remembered (a point which I have not mentioned before, as its application is better seen here) that the spectra are always produced in a direction at right angles to that of the lines, as is seen in Figs. I and II, where the lines are vertical, whilst the spectra are horizontal. In the case of the cross lines we are now considering, the horizontal spectra are due to the vertical lines, and the vertical to the horizontal ones. So a line inclined at an angle of 45° — say, for instance, a diagonal drawn from the top left to the bottom right-hand corner of Fig. Ill, would produce spectra ranged in a line parallel to the other diagonal. It will occur to you that these do actually exist in Fig. IV, and that, therefore, if we place at the back of the object-glass a diaphragm like Fig. D, only the spectra along the one diagonal will be admitted. When this is done, the rectangular lines entirely dis- appear, and are replaced by lines parallel to the other diagonal, as shown in Fig. d — a very striking example of the production of spectral lines. If the diaphragm had two slits at right angles, a second set of lines at right angles to the former would have appeared, forming a network smaller than the original ; so that, in lieu of the true object with vertical and horizontal lines, we should DIFFRACTION IN MICROSCOPIC VISION. 85 have one in which the lines are oblique — a purely illusory appearance. It results from similar experiments with these diffraction images that it is not possible to determine the real structure of P. angulatum merely from its image as presented by the microscope. With an object- glass of large angle, it appears, as is well known, to be covered with hexagonal markings, and when the diffraction spectra are examined, they are seen to be six in number, ranged round the margin of the field at equal distances, with the dioptric beam in the centre. These hexagons are not, however, necessarily a true appearance, for some entirely dissimilar objects may be made to appear with hexagonal markings by cutting off all the spectra except the six just mentioned. Thus a set of lines, which, crossing one another at an angle of 60°, form in reality rhombic spaces, presents two rings of spectra — the inner one identical in position with that of P. angu- latum. The rhombic spaces may be made to appear hexagonal, simply by reducing the aperture by a diaphragm, so as to exclude the outer and include only the inner ring. Or, again, by varying the combinations of the spectra, different sets of hexagons of varying size and position may be produced, all of which cannot, of course, represent the true structure. It is thus seen that dissimilar structures give identical microscopic images, when the difference of their cliffractive effects in the micro- scope is removed, and that, conversely, similar structures give dis- similar images, when their diffractive effects are made dissimilar, the moral of the whole being, as Prof. Abbe puts it, that minute structural details (as stria, &c.) are not, as a rule, imaged by the microscope, geometrically or dioptrically, in accordance with the real detail of the object, and cannot be interpreted as morphological, but only as physical characters — not as images of material forms, but as signs of material differences of composition of the particles com- posing the object ; so that nothing more can safely be inferred from the image as presented to the eye than the presence in the object of such structural peculiarities as will produce the particular diffrac- tion phenomena on which the images depend. In conclusion, I may mention that we are favoured to-night by the presence of Mr. Stephenson, the Treasurer of the Royal Micro- scopical Society, who first drew the attention of that Society to Professor Abbe's theory, and who has kindly come to exhibit, under the new oil-immersion objective (made on his suggestion at 86 P. CRISP ON MICROSCOPIC VISION". Jena, and having an aperture exceeding that of a dry lens of 180° by- no less than 25 per cent.), the object which excited much interest at their last meeting, viz., P. angulation with the whole of the central dioptric beam stopped out, and shown by the diffraction images only. The hexagons have entirely disappeared, and are replaced by what look like round holes punched out of the groundwork of the valve — an appearance which, it is very interesting to observe, had, unknown to Mr. Stephenson, been previously calculated by a pupil of Professor Abbe, who had never seen P. angulatum, and to whom the problem was set as a pure mathematical and physical one ; his solution of it even takes into account a peculiar semi-transparency which the groundwork shows. This experiment, I may mention, disposes of another fallacy that has its advocates, viz., that the central part of the objective is essential to fine definition. In leaving the subject here, I think it will be admitted that it is a very important one, and it is not a little surprising that so few microscopists have hitherto appreciated its importance or the revolu- tion it makes in microscopy.* * A reference to this subject would be incomplete without a mention of Dr. Fripp, of Bristol, to whom the thanks of English microscopists are due, for having, at the cost of much labour, presented them with a translation of Prof. Abbe's original communication in addition to numerous papers of his own, written with the view of further elucidating the subject. 87 ADDRESS BY THE PRESIDENT, Henry Lee, Esq., F.L.S., F.G.S., &c. (Delivered at the Annual Meeting, July 26th, 1878.J Gentlemen, — At the termination of my period of office you will expect that I shall offer to you a few valedictory remarks, to which I shall venture to add some brief suggestions. In my address last year I reviewed the progress of microscopical science, especially during the previous thirty-six years ; more, I think, with reference to the love of that science and a yearning for further knowledge having led to the foundation of the Quekett Club, than to any especial influence on the advancement of microscopy attributable to the club. I claim for the Quekett Club that its members have contributed their full share towards microscopical researches, and to the inven- tion of apparatus by which those researches are facilitated. But there is one branch of investigation to which I think increased attention may advantageously be given. We have had the micro- scope before us during the periodical meetings of the club in almost all its aspects except one, and that one has certainly not been developed to its fullest capacity. I allude to that which may be called " the commercial relations of the microscope." The practical application of the microscope to the things of every- day life is something more than merely commercial microscopy. It is just that phase of microscopy which commends itself to the utilitarian, inasmuch as it furnishes a complete answer to the question, " What is the use of it ? " As a rule, I have little respect for the mere utilitarian standard ; but, as so good an answer can be returned to the utilitarian questioner as to the utility of the microscope in a money-getting and money-spending world, let us be prepared to meet such an one on his own ground, and furnish a reply of the requisite kind. There are so many phases of this side of the subject that I shall not attempt to elaborate them. I beg you to understand that in mentioning a few I am only endeavouring to suggest a train of thought — not to compile a list of topics. 1st. The microscope is, and may be still more than it is now, a 88 the president's address. useful instrument in the detection of crime and of criminals. In- stances will occur to many of you of cases in which the microscope has been applied to stains of blood, to fragments of hair, and in other ways, with great success. A curious illustration of this will be found in a suggestion made in France, during last year, in order to prevent the forgery of bank-notes. There are some large toad- stools, common everywhere in Europe, which are known by the scientific name of Goprinus. These, as they grow old and decay, melt into a black fluid of a permanent character, which has been used as ink. Under the microscope this fluid consists of uniform purple-black oval spores, which may be detected in the ink at any time after its use. The proposal in the " Bulletin de la Societe Botanique de France " was to the effect that bank-notes should be printed or signed with this ink, which could always be verified under the microscope. I believe the obstacle to this was that there was no way known of manufacturing this coprin ink which forgers themselves could not employ. 2nd. The microscope may be useful in establishing innocence, as well as detecting crime. I had the great pleasure, some years ago, by means of the microscope, to save the reputation of an honest man, and prevent his being dismissed from a situation in which he had faithfully done his duty for many years. As, although I have frequently mentioned the incident in conversation, it has, I believe, never been published, I will record it here, as apropos to my sub- ject. My deceased friend, Edward Blyth, the learned Indian zoologist, one day brought me a few fibres of fine hair, with an earnest request from a certain noble lord that I would, if possible, ascertain to what animal they had belonged. He was under a strict promise, he said, to give me no information, except that a matter of grave importance rested on my answer. Of course, I carefully examined the few fibres submitted to me, and was soon able to decide that, beyond a doubt, they were the hair and wool of a hare. I was enabled to arrive at this conclusion with the greater ease and certainty that I had just previously been engaged with " the micro- scope in its commercial relations," in minutely examining with a view to comparing their structure with their relative felting proper- ties, the various furs used by hatters, amongst which is hare's wool. Poor Blyth was a very excitable man. When I told him my decision he shook my hand, and the tears rushed to his eyes, as he ejaculated " Thank God for that ! " And then he danced about the THE PRESIDENT'S ADDRESS. 89 room, and gave way to so many exuberant expressions of delight that for a minute or two I could not obtain from him the explana- tion I was longing for. At length, he told me that a gamekeeper in the service of the nobleman referred to had been accused to his master of having been seen to trap a fox, cut it open, disembowel it, and carry it home with him to hide his misdeed. As vulpicide in a hunting country is regarded as an offence about as heinous as child- murder, the keeper would inevitably have been dismissed in disgrace if the charge had been proved against him. His story was that he had found a hare in a trap set by a poacher, whom he had deprived of his expected prize by taking it home for his own dinner, after paunching it on the spot ; and he added that the man who made the accusation was a troublesome poacher, and the owner of the trap, who had a spite against him because he kept a keen watch upon his movements. As the latter persisted in his accusation, the keeper's knife, with which he had opened the animal in question, was examined ; and, in the hinge of the blade, were found the hairs sent to me. My reply completely confirmed the keeper's statement, restored him to his master's confidence, and baffled the malignity of a scoundrel. Two or three years ago an action at law came on for hearing in the North, in which a large field of onions having been blighted and destroyed, certain persons were sued for having caused the evil by the smoke of their neighbouring works. On the trial these damaged onions were produced, and proved to have been destroyed by a parasitic rust, which filled all the tissues of the plants, and killed them. The microscope gave an answer to the action, and the suit was lost. Last year a similar trial took place in Edinburgh. A large number of evergreens and other trees were covered with a black coating like soot. It was assumed that this, also, was a case of smoke nuisance, and an action was commenced against the owners of certain chimneys. On the trial the report of our Foreign Secre- tary, Dr. M. C. Cooke, showed that the black substance was not soot, but organized vegetables — algse and fungi — capable of germi- nation ; and, again, the microscope prevailed. In both these instances had the simple precaution of microscopical examination been first employed large sums of money would have been saved by those who, having suffered supposed injury, attributed it ignorantly to the wrong cause, and experienced defeat. 90 THE PRESIDENT'S ADDRESS. 3rd. Tlie microscope is useful in protecting us against commercial frauds. Most of you are acquainted with Dr. Hassall's book on the adulteration of food ; and from it you will have learned how effective an instrument is the microscope in the detection of adultera- tions. A friend of mine, who is known to be a most indefatigable microscopist in the locality where he has resided for twenty years, called on his grocer for some article of domestic use — arrowroot, I think — and was astonished by being told by the tradesman that he had none to sell. He remarked, in surprise, that he had seen some weighed a few minutes previously. " True," said the grocer, " but I can't give you that — you are too handy with the microscope ! " Not only in articles of food, but in clothing also is this protection afforded by the microscope. Some few years since one of our mem- bers, Mr. Suffolk, was engaged in a long series of experiments and examinations with the microscope and polariscope on the structure of flax, hemp, jute, cotton, and similar fibres. As a consequence, he was subsequently appealed to on more than one occasion to determine the character and extent of mixtures found in woven fabrics. Although this is an operation of great delicacy, when applied to fibres so similar in structure as jute and hemp, it is comparatively easy to detect the admixture of cotton with hemp, or of jute with silk. 4th. The microscope may be useful in the detection of concealed dangers to health. Some time since great consternation prevailed on the subject of trichinosis. All the evidence then adduced con- cerning the trichina encysted in diseased pork was founded on microscopical discovery. Instances might be multiplied, of course, of what has been done and what may be done to render the micro- scope valuable in commerce and in every-day life ; but I shall rest satisfied with having suggested thoughts which may be pursued at leisure. I fear that some of the elder members of our fraternity may consider my remarks somewhat elementary ; but it is my duty, as President of a Club like ours, to bear in mind that there are constantly joining our ranks recruits, to whom the microscope is new, and who have a right to expect guidance and assistance. That such incidents as I have mentioned could have occurred is sufficient proof that our Club, and other kindred Societies, may do good service by impressing upon public opinion the practical utility of the instrument from the use of which we derive so much intel- lectual enjoyment. In some quarters practical men are desirous of THE PRESIDENT'S ADDRESS. 91 enlisting the microscope in their service. I recently received a com- munication from the Manager of a large brewery, inquiring whether, and to what extent, the microscope might be expected to afford assistance in the operation of brewing. Some of the most formid- able difficulties of a brewer are connected with the process of fermentation. This subject has had some little attention from workers with the microscope, and it is not surprising that, having learned this, manufacturers should ask us whether we can furnish them with any practical results. The acquisition of knowledge and the cultivation of science are delightful and beneficial of themselves, but, in my opinion, the highest object of science, and the greatest use of knowledge is that they be made practically advantageous and beneficial to mankind. It is this feeling which has suggested the tone of my remarks to-night. Before I retire, there is one paramount duty incumbent upon me, and that is to thank you all for the hearty and cordial support which you have given me during my two years of office. It would not have been possible for the officers of the club, its committee, or the members generally, to have supported me more efficiently and kindly than they have done. Hence that which might have been two years of irksome and arduous duty has been to me, on the con- trary, a period of pleasurable enjoyment. I need not recount the history of this period, but I trust that during the more brilliant career of my successors in the Presidency, we may be able to look back upon it with satisfaction, and that there may in the future be moments when we may revert with pleasure to incidents of the past two years. Like all its predecessors, this has been a season of harmony and unanimity of action, although not, of necessity, one of unanimity of opinions. As I first occupied this chair surrounded by all the evidences of good feeling, so, now, I leave it with the happy consciousness that there has not occurred one instance of dissension, discord, or schism, unfortunately but too common in large societies. It is no small honour to this club that throughout its career it has been conspicuously remarkable for the absence of party feeling and cliques. The good fellowship of the whole body of its members having been averse from this mischievous tendency has evidently been one of the causes of its unexampled success. We still remain, as we were ten years ago, a club ; we still adhere to our old programme of sociable microscopy : and if the world has not been astonished by our great discoveries in science, it has, at H 92 THE PRESIDENT S ADDRESS. least, learned that five or six hundred persons can combine to cheer and strengthen and help each other in a favourite pursuit in perfect harmony, because thoroughly in earnest. The best counsel that I can offer you on this last occasion of my addressing you from the chair is that you seek to maintain in the future the same features which have contributed to your success in the past ; that you keep yourselves acquainted with the early history and development of your club ; that you continue to bear in mind the objects and aims of those who first called it into existence ; and that the original programme, which is always regarded by your officers and committee as their " Articles of Faith," be also your creed, and its principles be maintained by you as inviolable as a Royal Charter. I have seen the prosperity of societies diminished by imprudent changes in the conduct of their affairs ; and, by the loss of their original tone, their warmest supporters estranged, their ardour damped, and their affections alienated. There appears to be no danger at present of any such mismanagement of our own club, therefore a word of warning may be the more freely given against such a contingency in the future. Do not be too anxious for inno- vations, alterations, new modes of action, or experiments which would involve any modification of the club, more or less change its character, and thus render it less fitted for the position it now occupies. From so large a body of members there will necessarily, from time to time, proceed suggestions and proposals inspired by the best intentions, and which will doubtless always receive patient and careful consideration. Let me urge you always to test them rigidly by the principles of your " charter," and ascertain whether they involve any departure from the original plan adopted by the founders of the club, and maintained by you during twelve years of its exist- ence. If they do, reject them. And now I have one duty left ; it is to resign the office to which you did me the honour to elect me two years ago, to one far more competent than myself, and in whom we recognise all that we could desire in our President. I lay down my authority with supreme gratification that I am succeeded therein by one of the first spirits of the age, by one whom I have been accustomed to look up to with profound admiration and respect as a great master in science, whose name is known and revered wherever the English language is spoken. I hoped that Professor Huxley would be here this evening, but before he was made aware of the date of our meeting he had THE PRESIDENT'S ADDRESS. 93 inevitably engaged himself elsewhere, and he wishes me to convey to you his apologies for his unavoidable absence. My respect for him and for you will lead me to regard it as an agreeable duty to be present at the meetings of the club during his term of office if my health permits ; that I may have the privilege of listening to his observations when he is able to preside, or that I may act as his substitute, in turn with my fellow vice-presidents, in his absence. In this I shall only be following the good example of my excellent predecessor, Dr. Matthews, to whom, separately and especially, I offer my grateful thanks for the kind and able support I have received from him. 04 PKOCEEDINGS. May 10th, 1878. — Conversational Meeting. The following objects were exhibited : — Filmy Fern Raphides, in situ, in very young leaf of black bryony Transverse Section of Fossil Wood from Coal ... Larva of Meloe cocatricosus ... Ovary of Rabbit Eggs of Water-snail ... Feather from head of Wild Duck Parotid Gland of Kitten Plocamium coccineum Meyerina claviformis . . . Section of Pearl Daphnia } Mr. F. W. Andrew. Mr. T. H. Buffham. Mr. A. L. Corbett. Mr. Mr. Mr. Mr. Mr. Mr. Mr. Mr. Mr. Attendance — Members, 62 ; Visitors, F. Enock. W. H. Gilburt. W. Goodwin. A. H. Halley. J. J. Hunter. A. D. Michael. B. W. Priest. F. Reeve. J. Woollett. 5. May 24th, 1878. — Ordinary Meeting. Henry Lee, Esq., F.L.S., &c, President, in the Chair. The minutes of the preceding meeting were read and confirmed. The following gentlemen were balloted for and duly elected members of the Club :— Mr. F. E. Beddard, Major Richard O'Hara, Dr. W. T. King, Mr. A. Southey, and Mr. Horace Wilmer. The following Donations to the Club were announced : — " The Midland Naturalist " " Report and List of Bristol Natural") History Society"... ... ... j " Lindberg's Monographia Metzgerise " ... "Manual of Autographic Printing" "Report of the Hackney Microscopical^) Society" ... ... ... ... ) "The American Journal of Microscopy" ... in exchange. " Hartog on Floral Structure " " The Medical Examiner" (weekly)... "The Statist" from the Editor, the Society. »> the Author, the Publisher. the Society. from the Author. ,. the Editor. >y 95 60 Drawings of Hepaticce in portfolio ... ,, Dr. M. C. Cooke. A Solar Microscope, by Adams ... ... „ Mr. M. J. Hallett. 1 Slide, Cheyletus fiabellifer ... ... „ Mr. Michael. 1 Photograph for the Album „ Mr. M. J. Hallett. The thanks of the Club were unanimously voted to the donors. A paper by Mr. Geo. Williams, " On an Apparatus for Facilitating the Use of Powell's Small Bull's-eye Illuminator for the Examination of Test Objects," was read by Mr. Curties (in the unavoidable absence of the author through indisposition). The subject was illustrated by diagrams, and by the exhibition of the apparatus in the room. Mr. B. T. Lowne gave an interesting resume of some of his recent researches on the structure of the eyes of insects, which had been lately made the subject of a communication to the Royal Society. Mr. Lowne commenced his remarks by observing that the eyes of insects were not only very pretty objects, but they were also objects of great interest, inas- much as they appeared to have a very different manner of subserving vision from that of the eyes of ordinary Vertebrates. The most probable explanation of the manner in which vision is effected by the insect's eye was that given by Johannes Muller many years ago, and which had since been thought to have been entirely disproved by the production of the multiplied images of objects seen through the eyes in the manner which had been often shown in that room. He believed, however, that he should be able to show that in nine cases out of ten Johannes Muller's view was correct, and that many insects had no lenses at all in the cornea. Attention was next called to the work of Dr. Grenacher on this subject, and to the distinctive forms of insects' eyes which he had described. In his typical or conic eye there was found first a cornea, which might or might not be lenticular ; then a body called the cone, consisting of eight distinct cells and formed of a glass-like structure of great transparency, from which proceeded some extremely fine fibres not exceeding the 30505 of an inch in diameter. These fibres could be traced down into the retina, and they appeared to be formed of some semi-fluid material, seeing that when broken they ran up into viscid drops. Below the cone was a rod-like body which went down into the retina. Grenacher's next form was what he called the Pseudo-conic eye, and which was the kind found in the fly. This consisted of a lens, a cup containing a fluid resembling water, then a remarkable body consisting of four cells, and lastly a kind of rod connecting it with the retina. In addition to these he also found a third kind which he called the a-conic eye, and considered to be a rudimentary form, and one which pro- bably remained so. Mr. Lowne then proceeded to examine these forms as described by Grenacher, and considered that there could be no doubt as to the existence of the conic eye. The Pseudo-conic form was that kind which used to be brought forward in opposition to Johannes Muller's view, and he had himself held to the same opinion at the time when he wrote his work on the Blow-fly. Since then, however, with improved means of investigation at his command, he had so far modified his opinion as to doubt whether it really differed much from the eyes of other insects, for he 96 found that at the bottom of the cup there were the four cells as in the others. He objected to the name, and proposed to call it instead the Hydro-conic eye, because it was found that although a cone existed in the eye of the pupa, its cells afterwards are replaced by fluid. In addition to these there was another form of eye which he believed no one except him- self had pointed out. This form was then minutely explained by reference to a diagram ; the cornea was said to be non -lenticular in shape, and the cone was described as consisting of four spherical bodies attached to deli- cate stems, which, in a modified form, passed down through the cup into the cornea. This structure was said to be found in all diurnal lepidoptera and in most of the grasshoppers. Another form of eye was then described by reference to a diagram, and shown to consist of a lens of very short focus, with a retina coming up close to it, the rods being all of a highly refractive nature, like rods of fine spun glass. Another form — found in Tipulse, Gnats, Bees, and Wasps — had spherical lenses, with a bundle of sixteen rod-like structures, beneath each of which had a curious little bright globule attached to it. He thought it possible that these peculiarities of structure might be of use in perceiving other rays than those which we called light, and that nocturnal insects might be able to see objects by reason of their radiating heat. The President said that at that somewhat late hour he would not encourage a long discussion, but would invite a few observations from any gentlemen present who might like to remark upon Mr. Lowne's very interesting communication. Mr. Chas. Stewart said it was a long time since he had paid much atten- tion to this subject, but he had listened with exceeding interest to Mr. Lowne's remarks, and hoped to reap considerable benefit from them, as he intended to look into some of these questions during the coming summer. As regarded the eyes of dipterous insects, he might say that instead of there being eight of the fibres he had in every case found the number to be seven. In a great number of them there was to be seen an exceedingly brilliant colouring in the eye itself, which rendered many of them such beautiful objects. Had Mr. Lowne any theory to explain this remarkable kind of tapeturn ? He believed he had found it to be due to a layer which existed between the individual lenses, and he fancied that it might have the same problematic value as the tapeturn lucidum in some of the nocturnal animals. A pupillary orifice in some species had also, he believed, been clearly made out ; some sections of spiders also led him to believe that there was little or no difference between their eyes and those of the in- sectidas. Mr. Lowne said with regard to the number of the rods, he had not stated the number as being at all precise. Four was, however, the typical number, but in a great many species seven were doubtless found, and it would be seen 'that they ran into one another and anastomosed in a very curious way. He had no doubt that what Mr. Stewart referred to was a true tapeturn lucidum, and that there was yet a good deal to be made out of it. As regarded spiders he must confess that there were a good many in- 97 accuracies in Dr. Grenadier's paper, but still he thought there must be fluid found in some species ; although not having investigated the subject, he could not say anything about it from his own experience. The President proposed votes of thanks to Mr. Lowne and to Mr. Williams for their interesting communications, which were unanimously carried. The proceedings then terminated by a conversazione, at which the follow- ing objects were exhibited : — Platino-cyanide of Magnesium Diatoms, in situ, on an Alga Pulex masculi... Section of Porcupine Quill ... Trophi of Flea dissected by Mr. Tatem Wolf Spider, Lycosa agretica Argas rejiexus ... Globules of Nitella flexilis ... Young Water Snails ... Geranium Aphis Eye of Insect... Water Spider ... Internal Dissections of Insects Siplionia elastica, &c. .... Cellularia cuspidata ... A New Rotifer Microscopic Drawings Fossil Sponge — Siphonia multi-costata Sherzolite from Pyrenees, &c. Medusa from Cory nee Toe of Mouse... Attendance — Members, 71 ... Mr. F. W. Andrew. ... Mr. T. H. Buff ham. ... Mr. W. G. Cocks. ... Mr. A. L. Corbetfc. ... Mr. T. Curties. ... Mr. F. Enock. ... Mr. H. E. Freeman. ,.. Mr. W. H. Gilburt. ... Mr. W. Goodwin. ... Mr. G. Green. ... Mr. A. H. Halley. ... Mr. G. Hind. ... Mr. J. J. Hunter. ... Mr. M. H. Johnson. ... Mr. T. S. Martin. ... Mr. F. Oxley. ... Mr. A. Hammond. ... Mr. Priest. ... Mr. G. J. Smith. ... Mr. T. C. White. ... Mr. J. Woollett. Visitors, 4. June 14th, 1878. — Conversational Meeting. The following objects were exhibited : — Leaf of Tea Plant ... Pinnule of Asplenium ad. nigrum ... Aulacodiscus Oreganus Dolichopus popularis mounted without") pressure Anatomy of Cercopis sanguineolata Desmids Salivary Gland of Rat Cyclops quadricornus... A New Rotifer Hymeniacidon maceleuta S Mr. F. Mr. T. Mr. C. W. Andrew. H. Buffham. G. Dunning. Mr. F. Enock. Mr. F. Mr. W Mr. J. Mr. T. Mr. F. Mr. B. Fitch. Goodwin. J. Hunter. S. Morten. Oxley. W. Priest. Attendance — Members, 56 ; Visitors, 5. 98 from the Editor, the Publisher. jj June 28th, 1878. — Ordinary Meeting. Henry Lee, Esq., F.L.S., &c, President, in the Chair. The minutes of the preceding meeting were read and confirmed. The following Donations to the Club were announced :— "The Medical Examiner'' (weekly) " Science Gossip '' "The Analyst" " The American Naturalist " " Proceedings of the Academy of Natural") Science, Philadelphia " (series extend- > from the Academy, ing over a period of five years) ... j "Proceedings of the Belgian Microscopical" Society" " Proceedings of the Royal Society " in exchange. the Society. >> » »» " Proceedings of the Watford Natural") History Society " ... ... ... ) " " Proceedings of the Geologists' Association " ,, the Association. "Annals of Natural History '' ... ... by purchase. "American Journal of Microscopy " ... in exchange. "Baker's Natural History of the Polyp" ... from Mr. M. H. Johnson. 4 Slides of Polyzoa ... ... ... ... „ Mr. A. D. Michael. 8 Slides of Flint Sections 4 Slides of Sponges ... 12 Slides The thanks of the meeting wer „ Mr. Ingpen. „ Mr. J. G. Waller. „ Mr. T. Curties. re unanimously voted to the donors. The following gentlemen were balloted for and duly elected members of the Club : — Mr. W. Brewster, Prof. T. H. Huxley, Mr. John B. Magor, and Mr. Richard J. Ward. The President reminded the members that as their next meeting would be the annual meeting, at which elections of officers for the ensuing year would take place, it would be necessary for them to proceed to nominate the gentlemen whose names would then be placed upon the list for ballot. The following nominations had been made by the Committee . — As Presi- dent, Prof. T. H. Huxley, F.R.S., &c. ; as Vice-Presidents, Dr. Matthews, Mr. Chas. Stewart, Mr. T. C. White, and Mr. Henry Lee; as Treasurer, Mr. Gay ; as Hon. Secretary, Mr. J. E. Ingpen ; as Hon. Secretary for Foreign Correspondence, Dr. M. C. Cooke. The members were then requested by the President to nominate such of their number as they might desire to fill four vacancies upon the committee in place of Messrs. Johnson, Oxley, J. Smith, and Rogers, who would retire by rotation. The following nominations were then made : — Mr. E. T. Newton, proposed by Mr. Curties, and seconded by Mr. Gay. Mr. Frank Crisp „ Mr. Lee „ Mr. Oxley. Mr. A. D. Michael „ Mr. Hailes „ Mr. Freeman. >> 99 Mr. F. Oxley „ Mr. Parsons „ Mr. T. Powell. Mr. A. de S. Guimaraens Mr. Crisp „ Mr. F.H.Ward. Mr. E. Simpson „ Mr. Terry „ Mr.F. H. P. Hind. The President announced that Mr. Hainworth had been appointed auditor of the accounts by the committee, and requested the appointment of another gentleman to act in that capacity on behalf of the members. Mr. Dobson was then proposed by Mr. Curties, seconded by Mr. Cottam, and elected in the usual manner. Mr. Frank Crisp then read a paper " On the Influence of Diffraction in Microscopic Vision," the subject being well illustrated by excellent coloured diagrams, and by objects and apparatus exhibited in the room, special attention being called to the exhibition of Pleurosigma angulatum by Mr. J. W. Stephenson with the new oil-immersion lens, and with the central dioptric ray stopped out so as to produce an image formed by diffraction spectra only. Mr. J. W. Stephenson, in reply to the President, said that Mr. Crisp had so completely exhausted the subject that he hardly knew if he could add anything to what had been said, except to point out that the experiment which he proposed to show with P. angulatum was merely the exclusion of the central dioptric beam, and that the effect of this was that the mark- ings were shown as bright circular dots punched ont of a beautiful blue ground. If every alternate spectrum was stopped out then hexagonal mark- ings were seen. With the oil lens the angle was so large that it took in spectra of the second order. Mr. Curties enquired if the appearance shown was to be considered as the correct view of the object ? Mr. Stephenson said they did not know what was the correct view. Mr. Ingpen said that what Mr. Crisp had brought forward as the rudi- ments of this subject formed the groundwork of the knowledge of a branch of microscopy which was of very great importance, and it was just in this way that one should bring forward the first principles of a matter which every one would agree ought to be well known, and could not be too widely or thoroughly understood. And he might add that he hoped the subject would be followed up not only by the members themselves, but also that further instruction might be given at suitable times of the application of the principles involved. As soon as the principles were explained in a paper, the subject became educational, and there was then great scope for explaining these applications to the members of the Club, to whom it could be shown how great was the advance thus made both in the theory and practice of the microscope. Mr. Frank Crisp briefly, by means of drawings upon the black board, showed how the intersection of three sets of lines naturally produced the appearance of hexagonal markings. The President then proposed a vote of thanks to Mr. Crisp for his excellent paper, and also to Mr. Stephenson for his kindness in coming down that evening to illustrate it. Carried by acclamation. Announcements of meetings and excursions for the ensuing month were 100 then made, and the proceedings terminated with the usual conversazione, at which the following objects were exhibited : — Double-stained Vegetable Tissues ... ... Mr. Curties. Soldier Beetle (Telephones melanurus) ... Mr. Enock. Foot of Human Foetus ... ... ... Mr. J. J. Hunter. Sections of Leaf of Irish Yew ... ... Mr. W. H. Gilburt. Syenite, &c. ... ... ... ... ... Mr. G. J. Smith. Also specially in illustration of Mr. F. Crisp's paper, objects and appa- ratus were exhibited by Mr. Crisp, Mr. Curties, Mr. Ingpen, and Mr. J. W. Stephenson. Attendance — Members, 54; Visitors, 2. Mr. F. Enock. July 12th, 1878. — Conversational Meeting. The following objects were exhibited : — Hairs of the Tea Plant Mr. F. W. Andrew. Head and Tongue of Sand Wasp (Cerceris~) arenaria), mounted without pressure ) Growing-point of Dahlia ... ... ... Mr. W. H. Gilburt. Damceus papillipes ... ... ... ... Mr. A. D. Michael. Mcidium urtlca, Nettle cluster cups ... Mr. H. J. Roper. Section of Ovary of Mallow ... ... Mr. J. Slade. Section of Stem of Gallium aparine ... Mr. F. H. Ward. ,, ,, Stachys sylvatica ... „ ,, ,, Scrofularia nodus „ „ Strawberry „ „ Gladiolus Section of Petiole of Parsnip Young Hippocampus (alive) ... ... ... Mr. T. C. White. Attendance — Members, 35 ; Visitors, 5. j> >> July 26th, 1878. — Annual Meeting. Henry Lee, Esq., F.L.S., &c, President, in the Chair. The minutes of the preceding meeting were read and confirmed. The following gentlemen were balloted for and duly elected members of the Club : — Mr. John Battersby, Mr. William Crockf ord, Dr. John McDonald , and Mr. Henry Morland. Two gentlemen were proposed for membership. The following donations to the Club were announced : — " The Popular Science Review " ... ... from the Publisher. " Science Gossip " ... ... ... ... „ ,, "Journal of the Royal Microscopical ~) ,. _ . , J * \ „ the Society. Society' ... ... ... ... ) 101 " The Medical Examiner " (weekly) ... „ the Editor. " Proceedings of the Belgian Natural") History Society " J » the Societ ^ " The American Journal of Microscopy" ... in exchange. " Annals of Natural History'' ... .. purchased. A New Micrometer on the principle" from Mr. Curties. recently described by Mr. Burch '} Some old Slides mounted in ivory slips be- ', Mr. B. W. Priest. } tween Mica, for the Museum. Portraits for the Album of Mr. M. H. Johnson and Mr. T. C. White. The thanks of the meeting were unanimously voted to the donors. The Secretary read the Annual Report of the Committee. The President said that having heard the report, he rose to formally move that it be adopted and printed in the usual way. He called attention to the reference which had been made to the donation of £20, which it had been decided to give to the building fund of University College, and which he felt sure would meet with the hearty approval of all present, seeing how largely they were indebted to the Council of the College for permission to meet in that room — a privilege which, no doubt, had greatly contributed towards the remarkable success of the Club. The adoption of the report having been seconded by Mr. T. C. White, was put to the meeting, and carried unanimously. The Report of the Treasurer containing balance-sheet, &c, duly audited, was then read by the Secretary. The President moved " That this report be also received, adopted, and circulated with that of the Committee.'' Mr. T. C. White having seconded the motion, it was put to the meeting, and unanimously carried. Mr. Reeves and Mr. Faulkner having been appointed scrutineers, the ballot papers were distributed, and the election of officers proceeded with. The President then delivered the customary Annual Address, taking for his subject "The Commercial Application of the Microscope,' and con- cluding his remarks by many useful suggestions and counsels to the members as to their future wellbeing as a Club, and by the expression of his thanks to those who had so ably and unanimously co-operated with him ia the conduct of its affairs during his two years term of office. The Address was listened to with great interest and attention, and loudly cheered at its conclusion. Dr. M. C. Cooke said that the pleasure with which he had listened to the very interesting address of their worthy President, led him to rise and ask the members to support him in proposing that the Address be printed and circulated with the Journal in the usual manner. He did so with great pleasure, because he was so fully aware how their President had worked for the wellbeing of the Club, and how heartily he had promoted its interests in every way in his power. Dr. Matthews seconded the proposal with entire satisfaction. Mr. Ingpen said that he had the greatest pleasure in supporting this 102 proposal, and as the President could not himself put it to the meeting he wonld do so. Having put the resolution to the meeting, it was carried by acclamation. Mr. J. G. Waller said the task had been committed to him of proposing a vote of thanks to the President, Committee, and Officers of the Society, for their services during the past year. As regarded the President, Dr. Cooke had already taken the words out of his mouth, and he could add nothing which more entirely expressed his own appreciation of his merits. Their Secretary was one whose labours were too well known to need any observations from him. The other officers well deserved the thanks of the Club, and the Committee had always performed their duties in an admirable manner, and he had very great pleasure in moving this vote of thanks to them for their labours. The motion having been seconded, was put to the meeting, and carried unanimously. The President said he could not forbear again expressing his appreciation of the work done by their esteemed Honorary Secretary — so painstaking, so punctual, so reliable, so business like, his services were of no common kind. He felt he must thank him personally for the assistance he had received from him during his period of office, and for the promise to continue to act as their Secretary to the end of his term, although intimation had been given of his strong desire to resign. He was also glad to be able to announce that Mr. Ingpen bad consented to continue his duties as secretary to the end of Professor Huxley's term of office as their President. The President then moved the thanks of the Club to the Council of University College for the continued privilege of meeting in the library of that building. He was sure that every member who was in the habit of com- ing there must feel grateful to the Council for their kindness in this matter. The motion was carried by acclamation. Mr. T. C. White said he had a pleasing duty to perform in proposing a vote of thanks to the auditors and scrutineers for their services in connec- tion with the accounts and the ballot. Dr. Matthews having seconded the motion, it was put to the meeting and carried unanimously. The President said there was one other person to whom they owed a good deal — in a quiet corner next the Secretary sat Mr. Lewis, their honorary reporter, who from the first had carried on his work without emolument or remuneration, and this so quietly that perhaps there were many amongst the members who were not even aware of it. They all thought, however, that the time had come when they might and would offer him some token of their thanks, and as they felt that it would not be in accordance with his wishes that they should draw upon the funds of the Club for this purpose, the Committee and a number of the members had joined together in the matter, and he now had the pleasure of presenting to Mr. Lewis a testi- monial of their feelings towards him in the form of a gold watch, which he asked him to accept in their name, and to wear as a token of their esteem for the service which he had thus for so many years rendered to the Club- The President then handed to Mr. Lewis a valuable gold watch, the case of 103 which was beautifully engraved with his monogram, and inside which was also engraved the following inscription : — " Presented to Mr. R. T. Lewis by some of his fellow members of the Quekett Microscopical Club, in appreciation of his seiwices as honorary Reporter. July 26th, 1878." Mr. R. T. Lewis expressed his warm thanks to the President and to those gentlemen who had been associated with him, not only for the very hand- some testimonial which had been placed in his hands, but also for the very kind way in which the presentation had been made. He was extremely glad to have been able to perform any service to the Club, and his position might be explained by a reference to how he came to undertake it in the first instance. The idea was started at the meeting of the Club in October 18ii6, when a gentleman to whom they had so often been indebted for usefnl suggestions, Mr. (now Dr.) M. C. Cooke, expressed his opinion that the meetings of the Clnb were becoming so important that some permanent record of them was very desirable, and he hoped some member would be moved to volunteer his services in that direction. Accordingly during the following week he (Mr. Lewis) wrote to their then Secretary, Mr. By water, and offered to do what he could in the matter, stating that he did so from the desire to be a useful rather than a useless member of the Club. With this wish he had all along been animated, and he hoped, if spared to con- tinue the work, he might be yet able to do so for many years to come, being desirous to do what he could for the welfare of the Club, whose interests he had so much at heart. It had been a labour of love, and, thanks to the extreme kindness which he had always experienced from the three Secretarys with whom he had had the pleasure of working, it had never at any time pressed upon him as a burden, indeed from first to last the only cause he had for regret was that having one evening carelessly left one of his report books in a carriage in the Underground Railway, no amount of enquiry or offered reward sufficed to get it restored. He again sincerely returned his thanks for the very beautiful present which they had made to him ; he should value it for its own sake, but should do so far more as an expression of the good feeling of those many friends by whom he felt himself surrounded. The Scrutineers having handed in their report, the result of the ballot for officers and Council was declared to be as follows : — As President Prof. T. EL Huxley, F.R.S., &c. fMr. Henry Lee, F.L.S., F.R.M.S., &c. I Dr. J. Matthews, F.R.M.S. As, Vice-Presidents - *j Mr . C . Stewart, M.R.C.S., &c. I Mr. T. C. White, M.R.C.S., &c. fMr. F. Crisp, B.A., LL.B. To fill four vacancies on I Mr. A. D. Michael, F.R.M.S. the Committee ... 1 Mr. E. T. Newton, F.G.S. I Mr. F. Oxley. As Hon. Treasurer ... Mr. F. W. Gay, F.R.M.S. As Hon. Secretary ... Mr. J. E. Ingpen, F.R.M.S. As Hon. Foreign Secretary Dr. M. C. Cooke, M.A., A.L.S., &c. 104 The Secretary said that a paper had just been handed in which would be interesting as showing the results of one of their latest excursions — that of July 13th to Hampton Court. The water there was productive of a number of the most valued and beautiful microscopical objects. The excursion had been highly successful. He then read the following list (which had been prepared by Mr. Oxley) of the principal objects found on that occasion : — Polyzoa — Cristatella rnncedo, Plumaiclla repens. Rotifera — Melicerta rlngens, Limnias ceratophylli, iEctsiis crystallinus, Lacinularia socialis, Floscularia comuta, &c, &c. Infusoria — Acineta, Ophrydium, Anthoplujsa Mulleri, Arcella vulgaris. Hydra vulgaris (very large specimen), &c. Dr. M. C. Cooke said that on occasions like that when they caught any live object, especially one from a far distant place, they liked just to stick a pin through him, and exhibit him to the meeting. They had with them that evening a friend of his from the Far West, a member of the San Francisco Microscopical Society, and he wanted him to be able to go back and say to his brethren on the other side of the Atlantic that he had attended the annual meeting of the Quekett Microscopical Club, and that the members present heartily sent their greeting to their fellow -workers in that distant land. The President expressed the pleasure which he felt at seeing his friend Dr. Harkness amongst them as a visitor upon that occasion, and in the name of the members assured him of the hearty good wishes felt by all of them for the welfare and prosperity of the Society with which he was connected. Dr. Harkness said that he felt much gratified at this compliment, and should upon his return home convey to his co-workers an account of the reception he had met with from the meeting. The proceedings then terminated with a conversazione, at which the following objects were exhibited : — " Beetle found in Old Furniture " ... Cristatella mucedo, &c. Abdomen of Wild Bee, containing Male~^ and Female Stylops Spencii ... ) Cheyletus (alive) Trichinae (in situ) Attendance — Members, SO ; Visitors, 11. Mr. F. W. Andrew. Mr. Cocks. Mr, , F. Enock. Mr H. E. Freeman Mr. J. J. Hunter. 105 Ok the History and Structure of Corals. By John Matthews, M.D., F.R.M.S. Bead September 27, 1878. PLATE VIII. I have a few words to say by way of preface to the subject on which I am to address you this evening, and, if they appear to you to be somewhat egotistical, I ask you to believe that they seem to me to be absolutely necessary thus far, that I am able, in that way only, to set clearly before you the raison d'etre of this paper, and, therefore, to excuse me. I have ever held strict mutuality to be one of the most indispen- sable conditions of fellowship of this as well as of kindred societies. It is not enough that a man merely become a member. By doing so, he not only acquires certain privileges and advantages which he can scarcely rate too highly, but he— ipso facto — takes on himself cor- relative duties, the former immediate, the latter most probably post- poned — deferred — until he shall have passed his novitiate. His privileges are, to see, to hear, to observe, to question, and the more he exercises this last, the better for him. In due time, it is incum- bent on him to impart what he knows freely, to help by example, by lucid direction, by patient reply. It must be quite obvious to all who have long been members of this Club, that our conversa- tional meetings have done much to promote its prosperity, not only by the friendly intercourse, which is the natural result, but by the tacit obligation which they seem to enforce — that it is each member's duty to contribute in his turn, as often as he can, to the interest or instruction of the evening. It is an uneasy feeling of shortcoming on my own part in this respect, as well as another motive not less powerful, and which I will explain presently, that is the origin of this paper. Our field excursions are undoubtedly of the utmost value as feeders and promoters of search for the necessary objects for display and discussion on the gossip nights — or ought to be ; but it is cer- i 106 J. MATTHEWS ON THE HISTOBY AND tainly very quietly and below the surface — if I may use such an ex- pression. I cannot help thinking that their results ought to appear more frequently in the shape of papers and discussions in our trans- actions, to which they would impart an unfading interest and value. And now, in relation to my own share of the exchange on which I have laid so much stress, I must aver that it has ever been a cause of much regret to me that the excursions take place on a day of the week which my professional duties forbid my using for that purpose. My opportunities for the pursuit of Natural History are thus very rare. It is an almost trite saying, " that a medical man's work is never done," so that, as I very rarely know when I shall have a leisure afternoon, I cannot arrange to have the company of a friend, and thus such excursions are neither so pleasant nor so profitable as if I had the society and ready aid of some of the gentlemen whom I now see before me. To a great degree, then, I am compelled to rely upon my vacations, alas ! too few and far between ! Yet, out of them, I do manage to get work for a few months after, as you shall now hear. Some three months or more ago, I paid a visit to Llangollen. On a mantel-piece at the house of my friend there, whose wife is an ardent naturalist, an obelisk, fashioned out of what appeared to be black marble, attracted my notice, as it was evidently full of organic remains. On enquiry, I was informed that the stone came from a quarry near Corwen, a town west of Llangollen. Of course, I went there as soon as possible, and found that the formation was full of fossils, and presented features of the highest interest. I may also tell you that there is a range of lofty limestone cliffs, which I visited, called the Eglwyseg Rocks to the north of Llangollen, running parallel with the beautiful vale, and from two to three miles long, which has been extensively quarried, and is, therefore, easily open to inspection. This also abounds with similar fossils, of which 1 subjoin a list, furnished to me, by a local authority, and corrected by Mr. Newton of our club : — Corals (Ccelenterata.) Lonsdaleia (species of) Lithostrotion irregulare. „ basaltiforme . Syringopora juncea. „ reticulata. STRUCTURE OF CORALS. 107 POLYZOA. Fenestella nodulosa. Brachiopoda. Productus Llangollensis. „ giganteus. ,, spinulosus. Spirifera (species of) Terebratula hastata. ,, (? Spirifera) glabra. I brought some of my precious specimens home with me, being much pleased with the opportunity of being able to contribute by their help to the interest of our meetings. Having no means of ready access to the necessary Geological authorities or text books at the time, I was glad to be able to avail myself of the help of Mr. Newton, who prondunced them to be fossil Corals, and also kindly took the trouble to identify and name them for me. I had not then been able to examine their structure, but our members may re- collect that I disjDlayed some sections, which had been very nicely made by Mr. Smith, on our Gossip night, August 9th. Well, they were Corals. But I began to ask myself : What is a Coral ? What do I know about Corals ? Of course I had a general knowledge of them, but I was compelled to confess to myself that it was of a very hazy kind. Something I knew, certainly, of their structure and zoological place, but it was not all of a precise kind, nor such as I could — in default of the necessary precision — easily and honestly communicate to others, and I was far from being content with it. I then began to use my privilege of " Socratic questioning" — only to find that many of my friends were in very much the same condition as myself. A little more egotism, Gentle- men, and I have done. When I was a young man, my reading was not well directed — it was far too promiscuous and desultory. I was omnivorous, in fact. Much of the information thus gathered has clung to me — not always of the most useful kind, I fear. Still more has slipped away — alas ! of the more useful. Yet, all has not gone. I have now in my mind, stored there for more years than I care to remember, the substance of a paper which is to be found in one of the best of our English classics — the " Spectator." I am tempted to quote it to you now, because it embodies and insists upon that recognition of the labour of others, which I have taken 108 J. MATTHEWS ON THE HISTORY AND occasion to urge, in one of the addresses which I have had the honour of delivering in this place. It runs thus : You probably all recollect the good old knight, Sir Roger de Coverley ? Indeed you ought all to know him well. He has a domestic chaplain, whom he has made the parson of the parish. He had, " being afraid of being insulted with Greek and Latin at his own table . . . desired an old friend of his to find him out a clergyman, rather of plain sense than much learning, of a good aspect, a clear voice, a sociable temper, and, if possible, a man that understood a little of backgammon." He proceeds to say — " At his first settling with me, I made him a present of all the good sermons (both by living and dead authors) that have been printed in English, and only begged of him that every Sunday he would pronounce one of them in the pulpit. Accordingly he has digested them into such a series that they follow one another naturally, and make a continuous system of practical Divinity." He continues — i.e., the ' Spectator ' — not Sir Roger : — " I could heartily wish that more of our country clergy would follow his example . . . and would thus enforce what has been penned by greater masters. This would not only be more easy to themselves, but more edifying to the people." This, Gentlemen, is the second motive to which I just now referred, and, heartily coinciding as I do with the principle so genially laid down by the " Spectator," feel that it is equally appli- cable to the works of the great writers on Natural Science. I do not, however, propose to follow it literally on the present occasion, except so far as to endeavour to make you fairly well acquainted, as well as myself, with some j^art of the literature of the very fasci- nating subject now before us. Men who have been labouring hard in their daily avocations often dislike the labour of reading, and yet the mind though needing rest, is at least receptive ; 1 therefore venture to think that they will gladly listen to any one who will narrate to them, or at least set before them in some lucid way, an account of the labours of our masters in science as occasion may suggest. What I have done, then, and propose to do in the future — if the effort prove successful and acceptable to you — is to collect and collate, as succinctly as I can, all that I can gather on a given subject, together with such additions of my own as I may have been STRUCTURE OF CORALS. 109 fortunate enough to make. We must avail ourselves of the labours of others — or what would be the use of books ? What would the mechanical engineer do without his tables of strength of materials ! What the civil engineer without his constants — all of them the results of the labours of their predecessors ? And, if we be taller than our fathers, is it not because we are hoisted on their shoulders ? In this spirit, therefore, I now propose to lay before you a brief account of Corals. 1st. Their history — ancient and modern. 2nd. Their place and analogies in zoology. 3rd. Their structure — development — modes of offence and dejence, and their works* The time at my disjDOsal will not admit of more than a sketch — yet I hope a trustworthy one, of a very large subject. A very fanciful origin has been found for the word Coral, by which it was said to have been derived from two Latin words — " Cor "=the heart ; " alere "=to nourish. This idea is a relic of very curious old medical theory, which has long disappeared under the light of modern science, called the doctrine of Signatures. Under it most natural substances were imagined to possess some indications of their medical properties and uses, called " Signa- tures " — from "signum," Latin for a mark or sign — either by some fancied resemblance of shape or colour between them and the bodily organism, or by some peculiar taste or odour in the case of plants, and these were supposed to arise from astral influences. In the present case the fancied resemblance of red branching Coral to the heart and bloodvessels was thus supposed to indicate its uses in medicine, and hence its name. There are many relics of this old theory in the domestic as well as the classical names of herbs which were largely used in ancient pharmacy. But there can be no doubt that the real derivation is from two Greek words, which mean KOfjr) "Daughter;" \xA.os "of the Sea." The name "Coral" thus becomes singularly appropriate. The ancients did not know much of any Coral but the red variety, since that was the kind which was found most plentifully near their great centres of civilisa- tion, and they prized it greatly, adorning with it their helmets, * Commonly so called, but which are only the normal results of their life — their skeletons, in fact. 110 J. MATTHEWS OS THE HISTORY AND shields, and weapons. They wore it made into amulets to avert the " evil eye," and necklaces of it placed around the necks of new- born children were supposed to preserve them from contagious diseases, of which practice a relic still exists in the shape of the baby's coral and bells. It is found in many parts of the Mediter- ranean Sea, principally at the entrance of the Adriatic Gulf, the iEgean Sea, and on the coasts of France, Barbary, and Tunis. It is got up by a rude kind of dredge sometimes, but very rarely from water only ten feet deep, but is never found below 150 fathoms, generally at between about 60 to 100. That found in the Adriatic and on the coast of France is of the most brilliant colour, but in commerce there are five varieties, of which the rose-coloured is the most rare and valuable.* Of its modern uses I need not speak. The Corals belong to the Ccelenterata, the general characters of which are, that they have a distinct and permanent mouth, and a distinct and permanent body-cavity, but the mouth opens into, and freely communicates with the body cavity either directly or indirectly. The Ccelenterata are divided into two classes — -the Hydrozoa and the Actinozoa, and amongst both probably are found the Corals. The type of the former is the fresh-water Hydra, that of the latter, the Actinia, or Sea Anemone. The Hydra consists of a soft muscular bag, capable of being stretched into a slender tube, shrunk into a small globe, or widely distended, at will. At one end there is a circular mouth, highly sensitive, opening, closing, or protruding like a cone, and surrounded by from five to twelve (according to species) long and flexible tentacles, arranged symmetrically. The mouth opens into a cavity, which extends throughout the length of the body, and performs the office of a stomach ; but it is stated, as an extraordinary fact, which at present needs confirmation, that they appear to suffer no in- convenience from being turned inside out, the new cavity perform- ing all the functions of digestion as well as the old one. The other end terminates in a disc-like sucker, by which the Hydra fixes itself to aquatic plants. The whole sac, or bag, forming the body is made up of three layers, the Ecto-denn,t\\% Meso-derm more or less de- veloped, and the Endo-derm, and the space between is filled, according to my own observation, with a semi-fluid matter, having in it some ap- parently solid bodies and vacuoles, or ajDparently empty spaces. These * It is said by Mrs. Somerville that the white variety is a diseased form. STRUCTURE OF CORALS. Ill layers are united at the mouth, and each tentacle consists of a pro- longation of the layers of the body, enclosing a branch of the stomach, and having many stinging or thread cells. No hard skin layer is ever at any time developed in the Hydree. In none of them is there a haemal or blood system, nor a neural or nerve system, and aeration is effected by contact of the whole surface with the water in which they live. These creatures increase by budding, like plants. They are also hermaphrodite, being alternately propagated by buds and by eggs according to the season of the year. Dr. Carpenter says that this process of budding must be regarded as a modification of the ordinary nutritious process like the power of reparation so remarkable in all animals, but which exist in greatest degree among the lowest tribes, and especially in the Hydra, which may be cut into pieces, each part becoming a perfect animal. The Hydrozoa, then, may be defined shortly as those coelenterata in which the walls of the digestive cavity are not separated from those of the general body cavity, the two coinciding ; and the repro- ductive organs are in the form of external processes of the body, wall buds, in fact, on the one hand, or, of external protuberances, containing either spermatozoa, at the base of the tentacles, or ova, which appear in autumn towards the base of the column, forming a connecting link between gemmation, and ordinary sexual generation. The Actinozoa differ from the Hydrozoa in this important respect that they have a space between the digestive cavity and the general body cavity, i.e., the cavity bounded by the outside of the animal, so that it resembles a "vessel suspended in another by an upper turned-over edge, like a double glue-pot, the inner vessel having a hole below, by which it communicates with the cavity of the outer. The great family of Actinian Zoophytes, or Anthozoa, numbers many genera and species. The common sea anemone is the type of all such of them as inhabit the stony corals, and build the coral reefs and atolls of the tropical Pacific, they being essentially the same in structure, but having no sucking disc at the base. The sea anemone has a cylindrical body, attached at one end by a sucker to rocks ; at the other end is also a disc, more or less concave, having a mouth in its centre. This is usually elongated in one di- rection, and at the extremity of the long diameter are folds which are continued into the gastric cavity. It is surrounded by a series of tentacles, which vary considerably in number, but are generally in 112 J. MATTHEWS ON THE HISTORY AND multiples of five or six, and are tubular, usually retractile, smooth, generally more or less conical, but sometimes thread-like, and mostly richly coloured. You must all be familiar with these beautiful flower-animals, so that I need not say more about their external appearance. The soft smooth body consists of three layers — an outer (Ecto- derm), inner (Endo-derm), and intermediate, more or less largely developed (Meso-derm). It is provided with two layers of muscles, probably developed in the meso-derm, the fibres of which are antagonising, being longitudinal and circular. From the edge of the mouth is suspended a bag, which is the stomach. This has an opening at its lower end, by which its cavity communicates freely with the body cavity. Between the two are a number of thin partitions or folds, called Mesenteries, which connect them — some completely, others not — forming many interspaces, called loculi, and inter-communicating freely, their number and that of the tentacles generally corresponding, and the latter also open- ing at their bases into these interspaces. All these cavities are lined with innumerable cilia, -which keep up a constant circulation in the water which is admitted by the stomach into the whole animal, and which thus effect respiration, and, being mixed with the digested food, nutrition also. In these creatures, as in the Hydras, reproduction is " con- current " — i.e., it may be effected in the same organism by ovula- tion, or by gemmation, or by fission, which last seems to be the origin of the laminated forms of Corals which thus grow laterally. But there is this important difference between them — that in the Hydras it is wholly external, as I have before said, but in the Actiniae and the Coral polyps, while the individual is multiplied by buds, the species is multiplied by sperm and germ elements. The situation in which these elements occur, and their mode of conjunc- tion, are somewhat peculiar in this tribe. They may be hermaphro- dite, but generally spermatozoa are developed in cysts in the mesen- teries of the males, and when perfect are discharged into the stomach, whence they are at once ejected by the mouth into the water. In like manner the ova are first observed in the mesenteric folds of the female, and when mature are discharged into that cavity, which also receives the spermatozoa imbibed with the food. Very few things are more wonderful to me than this circum- stance, that the ovum remains in the stomach, after having been STRUCTURE OF CORALS. 113 impregnated, until it is hatched, and the progeny, a pear-shaped ciliated embryon, is discharged into the water by the mouth. Why- is it not dissolved with the food? There is one other part of the organism of these creatures which I must now notice briefly, viz., their thread cells, which are endowed with the most marvellous stinging powers, and from which the Acalephse take their name. With the exception of some of these, the thread cells of the sea anemone are more highly developed than in other animals of the class. During the act of contraction on being touched, a number of long filaments called Craspeda (fringes) issue through the walls of the body by almost imperceptible slits, with a stream of water from the chambers. These are covered with the poisonous stinging cells, by which the creature touched or entangled in them is para- lysed and rendered an easy prey. I call your special attention to these as interesting objects for microscopical examination and display. It is easy for you now to understand how the stony Corals and Madrepores are formed. The Coral polypes have the power of abstracting carbonate of lime from the sea-water, com- bined with a little animal matter, and a still smaller quantity of phosphate and sulphate of lime, with a trace of silver and magnesia. This stony substance takes the form of needles, a network is formed around the body of the animal, which, by a series of these deposits, is condensed into a hard impervious coat. The same process goes on simultaneously in the mesenteric plates near their bases, and in many of the Corals a horny column forms in the axis of the Polype, called the Columella, which is soon hardened by cal- careous deposit, and varies in structure in different genera. The horizontal septa which are to be seen more or less in all Corals, crossing the mesenteric plates — some of them at varying depths in each of the loculi, and called tabulas and dissepimenta — are evidences of the growth of the tenant upwards, since having left that part it has no longer any use for the space, and therefore cuts it off by a partition. Thus, the Actinious polypes may be said to possess an internal skeleton, and they also acquire an external one, in the form of a cylindrical coat, into which most of them can withdraw the soft upper part of their bodies and tentacles. The plates are some- times continued through the wall, forming ribs, which project, but are still covered by the ectoderm. By far the greatest number of Corals grow in size by budding, as the Astrasa, one of the deepest. They form groups in which the whole of the polypes, except their 114 J. MATTHEWS ON THE HISTORY AND starry summits, are connected by a living viscous substance, called C^enosarc, which, becoming consolidated by lime taken from the sea water, becomes what is called Ccenenchyma, or Scler- enchyma, so that the resulting Coral becomes a rounded mass, yet varying in shape according to the genus or species. The variety of compact or branching Corals far exceeds description, one hundred and twenty species being inhabitants of the Red Sea alone. The Millepora complanata, which, according to Mr. Moseley, of the " Challenger," is one of the Hydrozoa, is the largest coral known. This and the Porites, and one or two others, are the chief reef-building corals. They cannot live at greater depths than from 15 to 25 fathoms, for light and abundance of air are essential, and these decrease as the depth increases. In every case the polypes are alive only as far as they have free access to light, heat, and air contained in the water. The process of budding kills them also, for, when the buds proceed from the discs, or cups, of the star {i.e., are casspitose), the consequence is the death of the parent, and the formation of a new layer of the living above the dead. They thus increase vertically. Red coral was for a long time regarded as a marine plant, but is now well known to belong to a group of polypes called Alcyonaria, of which Alcyonium digitatum, an octo-corallum of Huxley, may be taken as the type. Its polypes possess eight fringed tentacles. If they possess sheaths, or cases, they are with- out horizontal septa or partitions. The mesenteries and body chamber are in fours, or multiples of four. And the corallum, if any, is sclero-basic, a term which I will explain presently, and they have abundant spicules in the sarcode. They are divided into Alcyonidse, Tubiporidse (organ corals), Pennatulidas (which include the sea pens, sea fans, cock's combs, etc.), and lastly the Gorgonidaa, to which the red coral of commerce belongs. I have now to set before you, as clearly as I can, the nature of the difference between this group and the reef-building corals, and to do this intelligibly, I must recall your attention to the three coverings of the Actinias and Hydrozoa, viz., the Ecto-derm, the Meso-derm, and the Endo-derm, as, upon the development of the corallum (for so the hard structure of the corals is called) in each of these is founded their classification. In the reef-building varieties, and in many others of the branch- ing kind, the hard structure is formed within the Meso-derm, and STRUCTURE OF CORALS. 115 in the intercellular substance of that layer of the body, and also of the mesenteric partitions, which form the loculi. Thus the calcifica- tion of the base and side walls of the body forms the cup (or calyx), while, in the centre, the columella is formed by the coalescence of the edges of the completed vertical mesenteric plates, called the primary, but sometimes independently. In like manner the " Pali," i.e., posts, or props, arise from those mesenteric plates, which do not reach the stomach — the secondary. These varieties are called sclerodermic, and the classification thus founded is comparatively easy to understand. They have what is called an " endo- skeleton. ," But the Gorgonidae-Isidse, and the rest of that class, which includes Red Coral, present at first sight greater difficulties. In all these, the Corallum is deposited outside the meso-derm, and although it forms the support (or axis) of the creature upon which the soft parts are spread, and thus appears to be inside it, it really is only so because the soft tissues, or sarcode, clasps it around. This axis is therefore outside the base of the actinozoon, and it is said to be Sclero -basic — to have an Exo-skeleton, like that of a crustacean. It arises thus — the ciliated embryo swims away, base forwards, affixes itself by its base to a suitable spot, and then begins to secrete corallum from it. Budding next occurs, and a branching coral is in due time the result ; but no calyx is ever formed by or in the corallum, the body of the polyj)e being retracted when required, into the soft parts which surrounds the axis, as the bark does a tree. Whatever the shape then, they may thus be distinguished from the Sclero-dermic kinds. Red Coral is, however, according to some observers, in part sclero-dermic, since it has spicules inside the meso- derm also. There seems, indeed, to be no absolute line of demarka- tion between the two classes. I will now try to give you a short account of the various kinds of reefs which are the result of the life of these animals. They are — 1st. Coral fringes, which lie very close to the land, and in shallow water. 2nd. Encircling reefs, lying in somewhat deeper water, and further from the shore around an island. 3rd. Barrier reefs, much further from the shore, about 60 or 70 miles off, and a hundred yards to a mile wide. That on the N.E. coast of Australia extends along the coast more than a thousand miles in length. 116 J. MATTHEWS ON THE HISTORY AND 4th, Atolls, or lagoon islands. These are rings of coral enclos- ing a lagoon, or portion of the ocean in their centre ; usually having an opening on the leeward side, and being apparently unconnected with any land. Structure or Coral-Reefs. — 1, Fringing-reef ; 2, Barrier-reef; 3, Atoll. a, Sea level ; b, Coral-reef ; c, Primitive land ; d, Portion of sea within the reef, forming a channel or lagoon. (From Nicholson's " Manual of Zoology.") Corals exist, like all other living things, under limiting circum- stances. These are light, heat, air, food, and probably electricity, though we know far too little of the part played by the last to be able to assign to it its due share in the general scheme. When the balance of these is disturbed, the organism affected by the disturb- ance endeavours within certain limits to conform to the altered con- ditions, or, failing that, perishes. I will now try to explain how this applies to the varying coral formations. 1st. Coral fringes are such as have existed undisturbed in all their vital and normal conditions, and along a coast line at moderate depths. 2nd. Encircling reefs are of the same formation and conditions, also undisturbed in their vital relations, but such as surround an island at the same moderate distance from land as the fringes. STRUCTURE OF CORALS. 117 Now, to explain the existence of barrier reefs, which lie so far from the land, and in very deep water, as well as of atolls, which have, apparently no land at all near them, we have to look for some dis- turbing cause which will account for their presence in depths quite fatal to the existence of the polypes, for all must die below the level necessary to secure light, heat, air, and food. This disturbance, Mr. Darwin has convinced us, we must look for in the slow subsidence of the crust of the earth. Corals can only live and flourish at depths of from 20 to 30 fathoms, and such a depth implies " no very great distance from land." Suppose, now, the bottom of the sea to sink slowly. Such corals as were at the lowest, being deprived of the necessary light, air, warmth and food, would die, and so not increase laterally, or outwards, towards the sea. But such as were near the surface would grow upwards, still trying to find subsistence by conformity to the new relations ; so that the upper edge would still remain awash with the sea, and thus flourish. Now, during this slow subsidence, the shelving coast line would evidently seem to be removed further from the reef by its submergence, and thus the distance of the barrier reef from land is explained. The same reasoning as easily accounts for the formation of atolls, since an island thus slowly subsiding must eventually disappear, leaving only the encirling reef to mark its position. We see, then, in each barrier-reef, a proof that the land has there subsided, and in each atoll a monument over an island now lost. The very deep and abrupt soundings outside both are thus also explained by the death and non-growth of the lowest corals. The lesser depth inside the reef is explained by the violent action of the tremendous surf in those latitudes, by the action of which masses of coral are broken off, carried over and inside the edge, and finally converted into coral sand and mud. Smaller and more delicate corals also grow inside, and help the process of diminishing the depth. One curious fact now remains to be noticed, namely, that in most, if not all of these reefs, if a well be dug, it will be found to contain nearly fresh, or very slightly brackish water, which makes them fit for the habitation of man. These wells ebb and flow with the tides, and, according to Mr. Darwin, " are common on some of the low islands in the West Indies." The compressed sand, or porous coral rock is permeated like a sponge with the salt water ; but the rain which falls on the surface, must sink to the level of the surrounding sea, and must accumulate there, displacing an equal bulk of the salt 118 J. MATTHEWS ON THE HISTORY AND water. As the water in the lower part of the great sponge-like coral mass rises and falls with the tides, so will the water near the surface : and this will keep fresh, if the mass be sufficiently com- pact to prevent much mechanical admixture ; "but where the land consists of great loose blocks of coral with open interstices, if a well be dug, the water, as I have seen, is brackish " (Darwin.) With this, Mr. Chairman and Gentlemen, I now conclude, earn- nestly assuring you that I have been speaking as a student to students, and that the best fate that I can wish for this paper is that it may arouse discussion, and perhaps excite criticism. In either case I shall be content, for my purpose will have been answered. Note. — I have been requested to append a few words on the relation of the microscope to Corals. I may therefore say that on every point they are essentially microscopic, their masses, though so great, extensive, and widely spread, being composed, for the most part, of microscopic units. Of course, the polypes cannot be examined in this latitude except by the light which their British congeners throw on them. But their hard structures can be instructively examined — 1st. By horizontal sections cut by the usual methods employed for very hard tissues. 2nd. By a plan communicated to me by Mr. Stewart, viz., splitting them vertically by the sharp blow of a hammer upon a razor; or 3rd. By splitting them by means of a pair of cut- ting pliers, such as are used for wire. By either of these last methods, the most interesting and beautiful structure is revealed, which is also so delicate that it would be quite destroyed and lost by grinding, and can be properly examined by the Microscope only. J. M. EXPLANATION OF PLATE VIII. Fig. 1. — Transverse section of a Hydrozdon, showing the body-cavity in the form of a single tube, enclosed by the body-walls. Fig. 2. — Transverse section of an Actinozoon .- s, Digestive sac; m, One of the primary mesenteries dividing the body-cavity into vertical compartments. Between the six primary mesenteries are seen the secondary and tertiary mesenteries, which fall short of the walls of the stomach, a, Ectoderm ; b, Endoderm. Fig. 3. — Diagrammatic vertical section of a Sea-Anemone : a, Mouth ; s, Stomach; b, Body-cavity ; cc, Convoluted cords ("craspeda') containing thread-cells, and forming the free edges of the mesentery (m) ; tt, Tentacles ; o, Reproductive organ contained within the mesentery. The Ectoderm (e) is indicated by the broad external line, the Endoderm (e 1 ) by the thin line and the space between that and the Ectoderm. Fig. 4. — Actinia rosea (after Gosse). Fig. 5. — Calicular gemmation as seen in Lonsdaleia jioriformis. Car- boniferous. STRUCTURE OF CORALS. 119 Figs. 6 & 7. — Diagrams of the arrangement of the septa in Zoantharia sclerodermata and Rugosa. Transverse section of a simple sclerodermic coral (Turbinolia), showing the theca, with its pro- jecting ridges, or " costee," outside, the visceral chamber and radiating septa inside, and the columella in the centre. Trans- verse section of a simple Rugose coral (Cyathophyllum), showing the wall, costae, and septa. Fig. 8. — Portion of four corallites of Favorites Gothlandica, enlarged, showing the tabulae. Fig. 9. — Portion of a Sclerodermic coral; branch of Dendrophyllia nigrescens, a compound sclerodermic coral (after Dana). Fig. 10. — Longitudinal section of Isis liippuris, a sclerobasic coral, exhibit- ing the external bark or ccenosarc, with its embedded polypes, supported by the internal axis or skeleton (after Jones). These figures are all taken, by permission, from Nicholson's " Manual of Zoology " (5th Edition). 120 On the Floral Development op Helianthus annuus. By W. H. Gilburt. {Read October 25, 1878.) PLATE IX. In the " Journal of Botany " for February of this present year there is a paper by Dr. Maxwell T. Masters, entitled " Side-lights on the Structure of Composites," in which, after describing a pro- liferous and in other respects abnormal specimen of Helenium autumnale, he raises the question as to whether the Composite possess a true calyx or not. In order to find an answer more or less satisfactory, observations were made, the results of which I now pro- pose to lay before you. Not that the examination of one species in an order containing 10,000 or more can in any sense be conclusive, but it may furnish a standard of comparison, and a point of departure. You will all doubtless be aware that the theory now held with regard to the various organs which go to make up a flower, is " that the calyx, corolla, stamens, and pistils are, notwithstanding their varied forms and functions, only modifications of one another, and all are, again, only modified leaves." However improbable this theory may at first sight appear, an acquaintance with the developmental history or morphology of the flower, and the fact that each and all are found reverting to the original type, will show that no other hypothesis yet advanced can be considered tenable. The order of development of leaves in all plants is strictly acro- petal, and consequently, regarding the various parts of the flower as modified leaves, they should be developed in the same order ; the lowest or outermost first, the others following in regular sequence. This law holds good in most, if not in all orders but the Composite, and here, from some cause, it is disturbed, and the calyx does not appear till late, if at all. In the species now under consideration, if a section be made of a very young capitulum, which is always found at the summit of either a primary or secondary stem, it will be seen that the apex of the stem has become depressed and extended in diameter, having THE FLORAL DEVELOPMENT OF HELIANTHUS ANNUUS. 121 the form of a slightly rounded cushion, over-arched by the modified leaves or bracts of the involucre, or what was at one time regarded as the common calyx of the compound blossom. Upon the surface of this cushion or receptacle, the florets, with their subtending bracts, are developed. The earliest appearance which they present in common with all young organs, is that of a hemispherical tubercle ; those nearest the circumference of the capitulum are the first to appear, development than proceeding in centripetal order. The tubercle, however, speedily loses its hemispherical form, and appears as shown in section in Fig. 1, being a circular protuberance with a flattened summit. The free edge now begins to grow more rapidly, and a hollow upper surface is the result, the margin of which is the commencement of the future corolla (Fig. 2). On the rudimentary corolla five rounded papillae arise — these are its lacinise or divisions — and growth still being more vigorous on the exterior, causes an over-arching of the corolla, so producing the valvate astivation which is one of the character- istics of Composites. An early stage of this is shown in Fig. 3. It is at this period of development that we find the first indica- tion of the stamens as five small projections at the internal base of the corolla, and alternating in position with its divisions. This is shown in section in Fig. 3. The Anthers of all Composites are syngenesious, or so united as to form a tube, the filaments being- free. This is brought about by the whole of the tissue, on which the staminal whorl originates, growing upward, so that what was at first but five papilla? is now a cylinder with five somewhat conical projections on its upper end. The tissue after a time separates near the base, at intervals corresponding with those which originally divided the stamens from each other ; growth is arrested in a tan- gential direction, thus forming the Anthers, but proceeds vertically at the original points of emergence, till the filaments are developed. Next in order arises the so-called calyx, as two projections at the base of the corolla, assuming at maturity the appearance of minute scale-like leaflets, or, as Sachs describes them, " sub-paleaceous Awns." If these are to be regarded as referable to the calyx, we note how late is their development — that which should have been first only just precedes, or is synchronous with the fourth whorl, for at this time we observe the first appearance of the pistil in the form of two semi-lunar prominences at the base of the stamens (Fig. 4) ; both the leaflets and the carpellary leaves of the pistil being arranged K 122 W. H. GILBURT ON THE radially — i.e., a line drawn through the centre of each would extend from centre to circumference of capitulum. The two carpellary leaves preserve their individuality for a time, until sufficient height has been attained to form the bifid portion of the pistil, then growth commences round the whole cavity of the floret, enclosing a small hollow space at the base, thus forming the future ovary — a condition shown in two stages in Figures 5, 6, and 7, Figure 7 being a transverse section of fig. 6. Growth now proceeds rapidly above the ovary, so that the cavity which was first at its upper part soon occupies its centre. While this is taking place, we observe at the base of the now elon- gated pistil — a growth of tissue which, when fully developed, appears as a cushion or collar, encircling the style — a cellular and generally glandular body, secreting nectar, and known as the disc (Fig. 8). Whether this is its function in the species under consideration, I have not been able satisfactorily to determine. There is one fact concerning this part of the flower which, so far as I know, has not hitherto been observed — at least, it is not referred to in any papers, nor shown in any figures that I have seen — i.e., the presence in comparatively large numbers of perfectly developed stomata. Whether they are accompanied by the usual intercellular spaces I am not able at present to say, the cell-walls of the disc being so extremely thin that it is difficult to decide whether two cells are in contact or not. The stomata however are so numerous, that on a disc — when only -^ of an inch in diameter — I have counted as many as 54. We come now to the development of the ovule, concerning which in some particulars authorities are not agreed. In the Composites we always find an unilocular ovary, and the ovule erect and anatropous, one question in dispute being whether the ovule is a development of the floral axis and also its termina- tion, or a lateral development upon it; some authorities, amongst them Sachs, holding the latter view. Kohne appears to regard it as a development from one of the carpels, but from which he was not able to say. It is difficult, however, to see how either can be supported in the species we are dealing with, as the first indication we have of the ovule is an uprising of the floor of the ovary, the centre of which is slightly conical, as shown in Fig. 10. True, in the earliest stages the base of the funiculus is somewhat inclined to the carpel which is nearest the centre of the capitulum ; but this fact seems to favour the hypothesis of the axial character of FLORAL DEVELOPMENT OF HELIANTHU8 ANNUUS. 123 the ovule, as, were it lateral upon the axis, and having regard to its direction of growth, which is always towards the centre, we should hardly expect to find it so inclined, but rather that its point of origin was nearer to the outer carpellary leaf, leaving a space for the rudimentary or suppressed axis. The terminal character of the ovule receives further support from the consideration of its after development, which points to the nucleus being the termination of the floral axis, the other point concerning which doubt exists ; those who regard the ovule as lateral, and consequently as a modified leaf, considering it a new formation on its superior surface. Growth of the funiculus from the first proceeds unequally, most rapidly on that side which is towards the circumference of the capitulum, the result being that its base speedily becomes horizontal, and that that point which was originally axial in position, and which seems to me to be the true floral axis, is by degrees forced over, and is found as a slight projection on the inner side below the summit. Figures 11 to 13 represent this at various periods of its progress. When the funiculus has attained the height of -^-^ of an inch, the first indication of the integument is seen as a ridge across its summit (Fig. 14), which, growing forward, forms a hood-like pro- jection over the now apparent nucleus, for the original apex has begun to grow faster than hitherto, and to keep pace with but slightly in advance of the integument. It has also altered in appearance and character, being clear and transparent, the cells being most distinctly nucleated. The young nucleus at first stands at right angles to the funiculus, but during development it is gradually depressed through an angle of 90°, and thus attaining its anatropal character (Figs. 15, 16). At length its further develop- ment is retarded, and it becomes covered by the integument, or primine, the ovule having but one envelope. Now having regard to the facts as above stated — first, that the earliest indication of the ovule is a rising of the floor of the ovary, with a bluntly projecting centre ; second, that growth proceeds more rapidly on the exterior side of the funiculus, by which the blunt point of the centre is gradually forced over, though never lost, that the nucleus is developed at this point at the same time, or just after the primine — it seems to me we cannot regard the ovule as other than a terminal structure, and the nucleus as the apex of the floral axis. Turning now to the question as to the presence or absence of a 124 W. H. GILBURT ON THE calyx in the Composita?, Dr. Masters refers in his paper to the various opinions held by botanists of authority upon the subject, and says, " For my own part, I am disposed from the facts above- mentioned, and from my examination of a large number of teratolo- gical specimens, to agree with those who, like Buchenau and Warm- ing, are of opinion that at present Composites have no true calyx, or only traces of it, and that the pappus consists of mere appendages or outgrowths not referable to distinct sepals. Buchenau suggests that pre-historic Composites had a five -leaved calyx, which has become effaced as time has rolled on, from the pressure exerted by the densely packed flowers." Then, after citing the opinions of Lund and Hofmeister, that each pappus hair, or scale, represents a sepal ; and pointing out that Warming, in opposition to this theory, shows that they do not correspond in position, nor agree as to period of development with sepals, and that the slight rim which forms beneath the corolla should be regarded as the true calyx, Dr, Masters says, " In all these points I am disposed to concur with the Danish naturalist (Warming), who further refers these organs to Trichomes rather than to Phyllomes, on anatomical grounds, upon the validity of which I am in no position to offer an opinion." In Helianthas we have two series of structures which have been referred to calyces by different authorities, viz., Trichomes, or hairs, which are found at the base of the corolla, and the two scale-like leaflets which surmount the ovary. Duchartre appears to have been the first to observe and refer the former to the calyx, and he describes their development, first as a ring of tissue, which afterwards, for the want of parenchyma, splits up into plates and eventually into hairs composed of a single series of cells. In this developmental history I cannot help thinking he was mistaken, as after a very careful examination of a large number of florets in all stages of development I have not been able to see them in any other form than that which he describes as the final one. Moreover, they do not occupy one plane, but extend over a considerable space ; they each have their origin in a single epidermal cell, and are but the termination, though more fully developed, of a series which extends upward from the base of the ovary. Again, if we regard them as representing the calyx, the difficulty as to retarded development is greatly increased (this Duchartre himself points out), as they are not seen till the ovule is well advanced. From these considerations it would appear that they are only refer- able to Trichomes. FLORAL DEVELOPMENT OF HELIANTIIUS ANNUUS. 125 With regard, however, to the two leaflets or scales there are certain facts which, as it seems to me, will prevent their reference to the same class of appendages, whether we regard them as sepals or not. " Trichomes," according to Sachs, " is the term given in the higher plants to those outgrowths which arise only from the epidermis, i.e., from the layer of cells which always remain the outermost in roots, stems, and leaves." According to Warming, they are of two kinds, viz., hairs, as we generally understand the term, and a emergences," the last being the strongest, and some- times containing a rudimentary vascular bundle. To this last class the tentacles of Drosera would belong. Now with the definition just quoted, the structures under con- sideration certainly do not agree, their origin being the same as that of all leaves — an extension of the Dermatogem and an outgrowth of the underlying periblem in the form of a tubercle. That they have a broad base of insertion is shown in Fig. 6, the dotted line representing their form and position at this stage of development. It will be observed that their point of origin, as shown in Fig. 4, is on a level with that of the carpellary leaves, and for some time this position is preserved, but ultimately, owing to more vigorous growth on the periphery, they are found surmounting the ovary (Fig. 9). At maturity they are leaf-like in form, with a serrated margin (Fig. 17). In section, at their thickest part I find six or seven layers of cells beside the epidermis. Up the centre from base to apex runs a fibro-vascular bundle containing four or five spiral vessels ; on either side there is another bundle, with a spiral vessel or two for about one-third their lengths ; these anastomose with the central one before reaching the apex. Outside these there are three bundles, still more rudimentary in character, and extending but a short distance into the lamina, in one of which there are no vessels. Both stomata and chlorophyll are absent. Simple as is the structure of these leaflets, and far removed as they appear from either leaves or sepals of the ordinary type, I think it can be easily shown that we have a series of links, almost complete, which will connect the two extremes with each other. In Figs. 18 to 22 are shown a series of bracts from one capitu- lum, Fig. 18 being at the same time the innermost bract of the involucre and the outermost floral one. Now between this and the ordinary foliage leaf examples may at once be found which will convince the most superficial observer that the one is but a modified 126 THE FLORAL DEVELOPMENT OF HELIANTHUS ANNUUS. form of the other, although in size, outline, and structure such a great divergence has taken place ; and continuing the series, we find bracts in which further modification has taken place, and which will, so far as structure is concerned, demonstrate that these diminu- tive scales, whether regarded as sepals or not, are certainly not Trichomes. Taking now the bract (Fig. 18), we find it abundantly supplied with chlorophyll, but which gradually diminishes in quantity as the bracts get farther away from the circumference of the capitulum ; this is shown in the figures, the shaded portions representing the decreasing surface occupied by it. Another feature to be observed is that they become greatly reduced in substance, and at last scale- like in appearance, the only part containing chlorophyll being that which, projecting above the floret, is exposed to the influence of light. Only one vascular bundle is present, that representing the mid-rib ; stomata are also absent, except upon the green portions ; the chlorophyll, the vascular system, and the stomata disappearing together, and were it not that some portion of the bracts were still exposed to the influence of light, we should find them in all respects as rudimentary as the two leaflets under consideration ; as it is we find they nearly approach each other. Taking then the facts above cited as to origin and structure, together with the circumstance that the subtending bracts of the florets do not differ much in the latter particular, I think we must conclude that they belong to Phi/ Homes rather than Trichomes, and if so, we can scarcely help referring them to the calyx, in spite of their retarded development and want of symmetry ; for if we regard them as bracts joined to the ovary, as Duchartre suggests, the same difficulty as to retardation presents itself, but in a greater degree. EXPLANATION OF PLATE IX. b. bract. co. corolla. s. stamens. cp. carpels. d. disc p. pistil. sp. sepals. a. apex. /. funiculus. pr. primine. n. nucleus. ov. ovary. sic. ovule. v. vessel. Figs. 1 — 9. Development of Florets; 6, Transverse section of fig. 7; dotted line, Fig. 7, position and form of sepals. „ 10 — 16. Development of ovule j 14 — 16, development of primine and nucleus. „ 17. Sepal, showing position of rudimentary fibro-vascular bundles. „ 18 — 22. Floral Bracts from one capitulum ; shaded portion indicates extent of surface occupied by chlorophyll. 127 On the Queen Bee, With Especial Reference to the Fertilization of her Eggs. By John Hunter. {Read Oct. 25th, 1878.) The life history, functions, and attributes of the Hive Bee, have for more than 2,000 years engaged the attention of Naturalists and other men of science. Apiarian students have numbered in their ranks men whose pre-eminent learning have left their names as land- marks to posterity, and who will never be forgotten while history exists. Among the ancient philosophers who have studied and written upon the Bee, I may mention Virgil, who devoted the whole of his Fourth Georgic to the subject ; Cicero, Pliny, Aristomachus, Philiscus, Columella and Celsus ; and within the present century we have the great naturalist, Swammerdam, the mathematician Maraldi, Reaumur, the inventor of the thermometer which bears his name, my illustrious namesake, John Hunter, the anatomist, and Huber, of Genoa, whose total blindness did not prevent his giving to the world many facts in the bee's life history which were before unexpected. Without approaching nearer to our own time, the above array of brilliant names as examples will sufficiently excuse any amount of attention we lesser lights may give to an insect so small, but yet of great and increasing service to mankind. When so many learned men have been before us, it may be assumed that the subject is well worn, but the fact is, that, from the imperfect means of observation enjoyed until lately, mainly by the miscon- struction of hives, facts have been so mixed up with surmises and wrong deductions drawn, that it became a difficult task to separate the true from the false. A colony of bees consists of workers which may number 50,000 or more, in summer a few hundred drones, and one queen, who is the only individual in all this vast assembly capable of propagating the species. At the present time, the month of October, we may safely assume that under normal circumstances the queen in any hive is the mother of every other bee there. The 128 J. HUNTER ON THE QUEEN BEE. drones are males, and what I have just said, will, of course, have informed you that the queen is the female ; and the question naturally arises,what are the workers ? They used to be styled neuters, but they are not so, they also, as well as the queen, are females, differing in the fact that their sexual organs are not fully developed. Drones, workers, and queens, of course, are all bred primarily from eggs, and those gentlemen who have made no special acquaintance with bee history, will perhaps feel surprised when I say that the eggs which produced the queen and the workers were, when deposited by the mother bee, identically of the same kind, and either could at the will of the bees, who may even be influenced by the will of the bee master, by skilfully directing them, as his agents, be made to give birth to either queens or workers — nay, I will even go further, and say, that 1 believe it possible that the skilful experi- mentalist could so direct that some selected eggs, which, left to themselves, would give eventual birth to drones, should be made to produce drones, workers, or queens at will. To elucidate this problem, I must beg your attention while I trace the history of a bee, not only from the deposition of the egg, but from the growth of the latter in the ovary of the mother, and it will also involve an explanation of the theory of Parthenogenesis. On dissection of a queen, we find within her abdomen a pair of ovaries, as on the diagram to which I direct your attention, as also to the preparation of these organs under the microscope. We see each ovary consists of a great number of tubes, containing eggs in various stages of development, and all these tubes lead to a right or left duct which again unites into one main channel down which the eggs pass ; at the side of this latter duct we find a little globular sac opening into the oviduct ; this sac is called the spermatheca, ' and is filled, when the queen has had copulation with the male, with the usual whitish seminal fluid, containing countless thousands of spermatozoa in full activity. I have here an impregnated queen, from which I will show you it is easy to dissect out the spermatheca, and verify its contents to be as I state. Seeing these active bodies all wriggling and twisting like so many eels, it is hard to believe they are not animalcules, as was long thought. To return to the eggs : when arrived at maturity they glide down the oviduct from either ovary, and on passing the opening of the spermatheca, receive one or more spermatozoa, which, penetrating the egg's substance, causes the birth of a worker larva ; but it may so happen that the egg in J. HUNTER ON THE QUEEN BEE. 129 its j>assage, does not, either from volition, or inability of the queen, receive impregnation, in this case it does not perish or addle, but gives birth to a drone larva, and it has been conclusively proved that the act of fertilization or not determines the sex of the future bee. The egg being fertilized and deposited, it hatches in about three days, and the young larva receives the careful attention of the worker bees, who feed it with appropriate food, and in due time it passes to the pupa state, on the 21st day becoming a worker bee, but the same egg that produced the worker in 21 days could, had the bees been so minded, have been bred up to a queen in 16 days. The bees only rear queens when necessity calls for them, either from loss of their old monarch or apprehended swarming. If I remove the queen from a hive, the first of these contingencies occurs, and after a period of a few hours' commotion, the bees select certain of the worker eggs, or even young larva, two or three days old, the cell is enlarged to five or six times its capacity, a superabundance of totally different food supplied, and the result is that, in five less days than would have been required for a worker, a queen is hatched. The marvel is inexplicable, how a mere change and greater abun- dance of food and a more roomy lodging, should so transform the internal and external organs of any living creature. The case is without a parallel in all the animal creation — it is not a mere super- ficial change that has been effected, but one that penetrates far below form and structure, to the very fountain of life itself. It is a transformation alike of function, of structure, and of instinct. On the birth of the queen, her wings are limp, and hairs clotted with moisture, but she is in full activity, the workers assist in her release from the wax-cell in which her transformation takes place, but they pay very little or no attention to her so long as she remains a virgin. The impregnation of the queen bee was long an enigma to Naturalists ; some have denied that any intercourse with the male was necessary for the fecundation of the eggs. Some supposed that the effluvia arising from the males within the hive was sufficient for this purpose. Maraldi thought the eggs were fecundated by the drones after they were deposited, in the same way that the spawn of fishes is fecundated ; but, from our extended means of observation, we are no longer in any doubt as to the modus operandi. From three to seven days after birth, the queen issues from the hive, on nuptial thoughts intent, and after circling a few times round her home, apparently taking its bearings, she flies away into space ; if 130 J. HUNTER ON THE QUEEN BEE. her trij) be fortunate, and she meets a drone, they fall together to the ground, where separation quickly takes place, at once fatal to the drone, who parts with his sexual organs, which remain attached to the queen on her arrival home ; these quickly shrivel up, and are removed by the workers. In the act of coition the spermatheca of the queen is injected with the seminal fluid, and, wonderful to relate, this small vessel whose external measurement is but -— of an inch, contains sufficient material to fertilize all the eggs which the queen may lay in her whole life (for she mates but once), although she may live four or five years, and deposit during this time more than a million eggs. Dzierzon, a highly scientific German bee-master, says, " Most queens in spacious hives at a favourable season, lay 60,000 eggs in a month, and a specially fertile queen in four years, which she on an average lives, lays over 1,000,000 eggs." On this authority I make this statement, and I do not think it is an exag- geration. Referring back to my text that " the act of fertilization [of the eggs] or not — determines the sex of the future bee," you may naturally ask how I prove this statement, or that the unfertilized eggs will hatch at all. Professor von Siebold made many most skilful microscopical dissections of eggs, and he affirms that among 52 eggs taken from worker cells examined by him, with the greatest care and conscientiousness, 34 furnished a positive result, namely, the existence of seminal filaments, in which movements could even be detected in three eggs, and among 27 eggs from drone cells examined with the same care and by the same method, he did not find one single seminal filament in any egg, either internally or ex- ternally. A phenomenon sometimes occurs in a beehive of a queen laying eggs that produce males only ; this for ages had puzzled philosophers, without any satisfactory solution, but if you will bear in mind what I have said, and admit it as fact, the solution is easy. The theory of Parthenogenises (or virgin breeding) which Dzierzon promulgated in 1845, is said to have explained this phenomenon of the beehive as perfectly as the Copernican hypothesis the phenomena of the heavens. The principal points to bear in mind are — that the queen to be able to breed workers must be fertilized by the drone, and that the union takes place only in the air — that drone eggs do not require fecundation, but that the co-operation of the drone is absolutely necessary when worker bees are to be produced — that in mating the ovaries are not fecundated, but the seminal receptacle (the spermatheca) and that the supply of semen thus re- J. HUNTER ON THE QUEEN BEE. 131 ceived is sufficient for her whole life-time. We prove these hypo- theses as follows : — Eggs laid in drone cells never produce aught but drones — a queen born with her wings imperfect rendering her unable to fly, or one born after drones are all dead (generally by August), and consequently unable to mate, lays eggs indiscriminately in both drone and worker cells, but all alike produce drones. The verification of this is very easy, we have but to deprive a stock of its queen in autumn, and provided there are eggs in the hive, young queens are sure to be reared, and as surely they will become drone breeders; the experiment has been so many times repeated that the fact is now incontestible. That a queen mates but once in her life, the introduction of the Ligurian bee into England enables us to prove. This variety has the reputation of being a better one than our own native bee — and it is a common practice to import annually from Italy fertile queens, which, by a little skilful management, are made to take the places of the rightful sovereigns in our English hives. The Ligurian bee is gaily striped with yellow bands, and we quickly find the original black bees are dying out, and replaced by the easily distinguished Italians, and while this naturalized queen lives, the bees of her hive are thorough-bred Italians. I will pre- sently dissect out, and display the contents of the spermatheca of a fertile queen, which will exhibit many thousands of the spermato- zoa, with their characteristic contorted movements. I will then perform the same operation on a virgin queen, when we shall find the contents of the spermatheca a limpid fluid only, not a trace of the spermatic filaments. My namesake, the great surgeon, attempted to fertilize drone eggs by artificial impregnation from the sperma- theca of a queen — he failed with the bee, but succeeded with the silkworm moth. Dr. Donoff is stated to have been more successful, and I see no reason why the experiment should at all times fail. Cases sometimes occur, when a hive is queenless, that one or more workers will develop the power of ovipositing ; it is reasonable to suppose from their diminutive size and general non-perfection of their organs, that the functions of the drone had not been performed ; certain it is that eggs of a fertile worker produce drones only, and in one solitary case, where such a worker came into my hands for dis- section, although I found ovaries and eggs, I could discover no sper- matheca. It has been a common subject for authors to dilate upon the respect and reverence bees pay to their queen, and the valour with which they defend her. This, although very pretty, I am sorry 132 J. HUNTER ON THE QUEEN BEE. to say, is all fable. The bees' attention to the queen is solely in interested motives, that is care for the eggs. A virgin queen receives no attention whatever, no defence is ever offered for the queen. I never hesitate to pick up a queen from the midst of her subjects, to which the bees pay no heed, and in cases where an eruption of strange workers takes place in the hive, the rightful inhabitants will suffer their queen to be seized and ill-treated by the intruders without resentment. A queen is possessed of a sting, but I have never known her use it as a weapon, except in combat with another queen — but it is probably used to direct her ovipositor when in use. 133 PEOCEEDINGS. The following paragraph was accidentally omitted from the Eeport of the Proceedings of the July meeting. Its place is in page 101, between lines 30 and 31. " Attention was called by the Secretary to the fact that since the last meeting two of the gentlemen proposed for election as Members of Com- mittee — Mr. Guimaraens and Mr. Simpson — had withdrawn their names ; the four remaining names would therefore stand to fill the four vacancies in the Committee, and the members would not be at liberty to strike out those names, or to substitute other names for those nominations, but they could do so in the case of the nominations for the offices of President, Vice- Presidents, Treasurer and Secretaries." August 9th, 1878. — Conversational Meeting. Mr. F. W. Andrew. Mr. F. Enock. Mr. W. Goodwin. Mr. J. J. Hunter. Mr. M. Hawkins Johnson. Dr. J. Matthews. The following objects were exhibited : — Exudation from surface of Terra-cotta ... Brilliant eyes of Crysops relictus (Cattle fly) Scale of Sole Thumb of Human foetns, injected Flint stained with acetate of roseaniline Fossil Corals from Corwen Micrasterias denticulata. mounted more than") ,, . ^ ,,. , , ,, ' s Mr. A. D. Michael. 1Z months ago ... ... ... ... ) Stems, &c, of Chara, in flint ... ... ... Mr. G. J. Smith. Section thorn of Gooseberry ... ... ""| " Bramble I Mr. F. H. Ward. „ Stem of Alisma plantago „ Flower of Butomus umbellafois ... J Attendance — Members, 35 ; Visitors, 3. August 23rd, 1878. — Ordinary Meeting. Dr. J. Matthews, F.R.M.S., Vice-President, in the Chair. The minutes of the preceding meeting were read and confirmed. The following gentlemen were balloted for and duly elected members of the Club:— Mr. John H. Steel, Mr. Washington Teasdale, Mr. George F. Watson. Four gentlemen were proposed for membership. The following Donations to the Club were announced : — " Science Gossip " ... ... ... ... ... from the Publisher. " The Medical Examiner " (weekly) „ „ Editor. " Proceedings of the Eoyal Society "... „ „ Society. 134 " Proceedings of the Belgian Microscopical Society " from the Society. The last volume of the Eay Society's publication ... by subscription. " Annals of Natural History "... ... ... ... ,, purchase. " Journal of the Cincinnati Natural History Society " from the Society. " Annual Report of the Brighton and Sussex Natural / History Society " ... ... ... ... J " Quarterly Journal of Microscopical Science " ... by purchase. " The American Naturalist " ... ... ... ... in exchange. " The American Journal of Microscopy " ... ... „ „ 10 Slides of Acari ... ... ... ... ... from Mr. Michael. A Photograph for the Club Album , ... „ Mr. H. Davis. The thanks of the Club were unanimously voted to the donors. The Chairman said it appeared that they were without any formal paper to be read that evening, but he had observed that when such was the case it often happened that the meetings were not the less interesting. He would suggest that the results of their vacation rambles would form very interesting topics for conversation. It was not matters of great importance which they desired, for, as microscopists, they did not despise the day of small things. Perhaps whilst others were preparing to say something, Dr. Cooke would be kind enough to offer some remarks upon some subject, which from him would be sure to be interesting. Dr. M. C. Cooke, having expressed his willingness to gossip for a few minutes, said that when one had ever so many ideas stored up in one's head, it was sometimes rather difficult to pick and choose amongst them at a moment's notice ; he had, however, had so much to do with one group of organisms, that it would be strange if he could not find something to talk about in connection with them. It was that old mouldy subject which always cropped up whenever he got upon his feet. One of the commonest things in the whole group was the common blue mould, and whilst he pro- ceeded to describe it, he would just for a moment assume that the members of the Club before him were a class of persons who had never before heard of such a thing as blue mould. They had doubtless heard something of a vinegar plant, a film of ropy substance which was often cultivated domesti- cally for the purpose of producing vinegar by letting it grow in any sweet mixture, such as sugar and water. In most cottages in the country they would find it to be well-known, and most cottagers were very proud of it J he had tried the vinegar of some of the most experienced producers, and could only say that he should be very sorry to call it vinegar himself. If this vinegar plant was exposed to the air, and its means of subsistence was allowed to get dry, it would no longer increase in its former manner, but it turned about to seek some other means of development. There were two phases of fungi — the reproductive and the vegetative. The common mush- room exhibited both of these ; the stalk, the cap and other portions re- presenting the vegetative growth, whilst under the cap were found a number of gills on which myriads of spores were developed, and these were the reproductive portions, and sometimes it happened that under special cir- cumstances, in the mushroom the reproductive growth became checked. 135 The vinegar plant was naturally vegetative only ; year after year cells were added to cells, and filaments to filaments, but there was nothing to be found about it of the character of a seed. So long as sweet water was supplied to it, so long it kept growing in this manner ; but if a check took place and it could no longer get what it wanted to feed upon, directly it began to starve, it shot up a number of filaments, and it became covered with a beautiful crop of blue mould. When these filaments were developed to their full extent, a number of chains of bead -like spores appeared at the top, hence this mould was called Penicillium. No end of these were pro- duced, and when the spores ripened and dropped off, every one was capable of producing a plant. Each chain, it would be observed, proceeded from a small branch, each of them growing in pairs, the top of the thread forked out into some elongated cells, and on these grew the chain of spores. If any member of the Club, who was desirous of studying these things, did not happen to possess a vinegar plant or a piece of mouldy bread, if he were to take up a small portion of fresh horse-dung and put it under a bell glass, in 48 hours he would have a strong supply of this mould. If they shook off some of these spores into a hollow glass slide containing a little sugar and water, they would in the course of a few hours be able to detect each one sending out a short filament, and branching out in various directions. Each spore would measure, say the 5 f )i7 of a millimetre or "005 of an inch, and each one was perfectly capable of producing a vinegar plant. Another mould, nearly of the same size, and resembling it to the naked eye, was found in similar places. The top of the stem is swollen and simple, the chains of spores are seated on elongated cells, which spring from the thickened apices of the threads. This is the Aspergillus glaucus. Another remarkable thing might be observed in this mould — when it grows on some substances, under favourable con- ditions, the mycelium at the base curled up at the ends in a curious way, twisting itself round like a corkscrew, until at length it became quite like a ball. It then became absorbed into a globose form, clear and colourless, and containing a number of globules. Gradually the outside wall thickened, it became of a yellow colour, and it was transformed into a fungus of a different character, belonging to a different group, and as widely distinct from its original type as a blade of grass was from a walnut tree. The structure of these globose bodies was an out- side reticulated wall containing cells called asci, these again containing eight small bodies called sporidia ; when the outside case broke, the ascus opened by a small lid, and the spores escaped, and each one of these was capable of producing not always something like itself, but either of the other species. This fungus was known as Eurotium herbariorum, and upon old specimens of dried flowers or insects they would often find these little golden balls, which were only another phase of the growth of a very common mould. The Chairman said that it had passed into a proverb that it was difficult to speak gracefully upon common things, but this task their friend, Dr. Cooke, had succesfully accomplished. He should be glad to hear 136 observations from any gentleman present npon the subject, though he thought they must admit that it was very difficult to come after Dr. Cooke, seeing that what he said was usually almost exhaustive. Meeting with no response, he then called upon Mr. Ingpen to give them some observations upon a question of great optical importance ; he need not tell them that much depended on how they saw things, the importance of the question often depending far more on hoiv than ivhat they saw. Mr. Ingpen then gave an account of the present state of the " angular aperture" question, and exhibited and described Professor Abbe's Apertometer. The Chairman invited observations upon the very interesting subject which had been placed before them, and thought that Mr. Ingpen had thrown a flood of light upon a matter which was a very difficult one. The presence of oil between the front lens and the object stood much in the same relation as the field lens of the eye-piece to the eye-lens ; it collected rays which would otherwise be lost. If the field glass of an eye.piece was taken out, they would still see the object, but only a small portion of it, though more magnified, but when placed in its position again they would find that the field lens gathered in many rays of light which would other- wise be lost. He might compare this effect to that of a number of wires surrounding a hyacinth in its glass ; they spread out very much until a ring was put round them to gather them together. Mr. Ingpen further illustrated this effect by a drawing on the blackboard. The thanks of the meeting were unanimously voted to Dr. Cooke and Mr. Ingpen for their communications. Announcements of meetings for the ensuing month were then made, and the proceedings terminated with a conversazione, at which the following objects were exhibited : — Stained tissue of Cystsopteris bulbife?'um ... ... Mr. T. H. Buffham. Lining of nest of English Trap-door Spider — Atypus^ „ , . ( Mr. F. Enock. Sulzeri ... ... ••• ... ... ••• t Section of leaf of Pinus sylvestris Mr. W. H. Gilburt. Pollen of Japanese Lily Mr. W. Goodwin. Various Anatomical Injections ... ... ... ... Mr. J. J. Hunter. Attendance — Members, 44 ; Visitors, 5. September 13th, 1878. — Conversational Meeting. The following objects were exhibited : — Cuticle of Water-cress, showing crystals and raphides Mr. F. W. Andrew. Elytron of Oak Weevil Mr. G. Beaman. Dentate Antennae of Goat Moth Mr. F. Enock. Frond of Stag-horn Fern, transverse section, double^ ^ ^ ^ Gnburt stained ... ••• ••• ••• ••• ••• ) Hairs of Deutzia scabra Mr. W. Goodwin. Section of Jaw of Cat, showing four teeth Mr. J. J. Hunter. 137 Cuticle of leaf of Fuchsia showing bundles of raphides Mr. C. Le Pelley. Polyxenus lagurus Mr. A. D. Michael Micro-rulings on glass 1,000 to 20,000 to the inch Compound vibration and Geometric curves ... Star ruled on glass by the late Mr. Stannistreet Larva of Coccinella bipuncta ... ... ... ... Mr. T. C. White Attendance — Members, 38 ; Visitors, 5. Mr. Washington Teas- dale. September 27th, 1878. — Ordinary Meeting. Charles Stewart, Esq., M.R.C.S., &c, Vice-President, in the Chair. The minutes of the preceding meeting were read and confirmed. The following gentlemen were balloted for and duly elected members of the club : — Mr. H. T. Ashby, Mr. Heneage Gibbes, Mr. George D. Plomer, and Mr. Eobert G. West. The following Donations to the Club were announced : — Proceedings of the Royal Mici'oscopical Society ... from the Society. ,, „ Watford Natural History Society ,, ,, ,, Eighth Report of the Croydon Microscopical Club ... ,, „ ,, Annual Report of the West London Scientific Asso-") ciation j" " " Proceedings of the Belgian Microscopical Society ... ,, „ „ " Science Gossip " ... ... ... ... ... „ „ Publishers. " The Analyst " .. . ... ... ... ... ... ,, „ ,, " The American Naturalist " ... ... ... ... in exchange. " The American Journal of Microscopy" ... ... „ „ " The Annals of Natural History " ... ... ... Purchased. 58 Slides of Acari ") Photograph of Mr. A. H. Halley, and a photograph of the grave of the late Professor Quekett, the latter presented by Mr. T. H. Powell. The thanks of the Club were unanimously voted to the Donors, and, on the motion of the Chairman, a special vote of thanks was accorded to Mr. J. F. Cocken, of Botsdale, for his valuable additions to the Cabinet. The Secretary read a letter from Dr. Alfred Carpenter, President of the Croydon Microscopical Club, inviting the co-operation of Members on the occasion of the Soirie of that Society, which was fixed for November the 6th. Dr. J. Matthews read a paper " On the history and structure of Corals," the subject being illustrated by numerous diagrams and by models and specimens exhibited in the room. The Chairman said that they had, by the applause which followed the conclusion of the paper, anticipated the proposal that he was about to L from Mr. J. F. Cocken. 16 „ Shells of Mollusca 138 make, namely, that their very best thanks be presented to Dr. Matthews for the very excellent paper which he had given them. The whole subject was one of extreme interest to Microscopists, and it was well known that the corals furnished them with some of the most lovely objects which they possessed, so that hardly a cabinet could be found which did not contain specimens of spicules and other portions from this interesting group. He would just point out one little matter in connection with the subject — it was formerly always taught that the septa of the stony corals were due to the calcification of the mesenteries ; this, however, was not the case, for it was found that the septa arose from an independent growth in the intervals between the mesenteries. The septum in the actinozoon corals was beneath the tentacles, whereas the mesentery was between them. He asked the members to return their hearty thanks to Dr. Matthews. A vote of thanks to Dr. Matthews was carried by acclamation. Mr. Hardy enquired whether any cause had been found for the red colour of the coral ? Also, if the cause of the stinging property of the anemones and hydras was explained ; was it electrical or something of a poisonous nature ? Dr. Matthews believed the stinging property to be the result of a purely animal poison, of the nature of which they knew nothing. As to the cause of the colour, he confessed himself to be utterly ignorant on the subject. Mr. Stewart regarded the colour as being in all cases organic in its nature ; in some cases it was clearly due to the colour of the fleshy part covering it. As regarded the stinging power, he had often watched the behaviour of prawns which came in contact with the anemones, when the anemone was taking its breakfast, for instance, and the prawn had tried to take it away. No inconvenience seemed to be suffered by the prawns, who, probably, were able to resist the stinging property, but a fish coming into contact with it exhibited great distress in consequence. Dr. Matthews said that Mrs. Somerville regai'ded the white varieties as diseased specimens, and he believed that the dealers also said it was diseased coral ; but they seemed ' to know very little about why they said so. Mr. Frank Crisp said he for one would be very glad if Dr. Matthews would carry out his idea of a series of papers, like the oue he had read that evening as he could hardly imagine anything more useful to them than such papers, which conveyed a great deal of instructive and useful information, though perhaps they might contain little which was absolutely new; and he should decidedly like to see a series of papers upon " What is Rotifer ? " " What is a Sponge ? " and so forth, in preference to endeavouring to obtain nothing but original papers. Another subject to which Dr. Matthews referred was that of their excursions. It had often been a matter of sui'prise to him that the excursions produced so little result in that room, and he thought that if those who went to them would preserve what they gathered and bring it to the Club on the gossip evenings, many of those members who could not go to the excursions would be only too glad to have some of the specimens. 139 Mr. Curties said he should like to ask a question on one point, and that was, whether Dr. Matthews could give them any information as to the form of preparation which should be adopted to make this class of objects into those pretty and instructive slides which they had so often admired ? Mr. M. H. Johnson thought Dr. Matthews had expressed the opinion that these creatures had the power of separating carbonate of lime from the water of the ocean. He was not aware that the ocean, at any distance from the land, contained carbonate of lime ; bat he thought it probable that it was separated rather as a sulphate of lime, and that the sulphur served some kind of purpose in the animal economy. Dr. Matthews regarded this as an extremely difficult question in animal chemistry, and one which it was not easy to answer without careful con- sideration. He called the attention of the members to a number of speci- mens upon the table, lent in illustration of the subject by Mr. Newton and Mr. Stewart, and expressed his thanks to those gentlemen for the valuable assistance thus rendered. Mr. Ingpen wished to say just a few words with respect to two or three remarks which they had heard that evening, H e felt sure that all must be thoroughly aware of the extreme value of such papers as that which they had just listened to ; it was one of a class which could not fail to be most useful, and of which they had already had a specimen in the valuable series of papers by Dr. Braithwaite, on the " Histology of Plants." He hoped, however, that they would not be too ready to adopt the advice of giving up the idea of original research, and letting all such papers drift to the Eoval and other Societies. Any one who looked through their Proceedings would find a number of original communications, some of which were of consider- able value and interest, and he should be very sorry indeed if it w r ere to become an established custom that any of their members who did any original work, or found out anything new, should feel bound to run off with it to some other Society instead of endeavouring to add to the reputation of their own. Whilst, therefore, he valued very highly such papers as that of the evening, he still hoped that those members who were thinking out matters for themselves, or who were making original observations, would none the less give the Club the benefit of them. With regard to the excur- sions, he wished they could have a little more information as to their results reported before the meetings j but it should be borne in mind that objects which had been collected at the excursions were frequently brought to the meetings. It was not very easy to do this at all times ; if, for instance, there were to be an excursion to-morrow, he should like to ask what would be the condition of many of the objects by the time of the next gossip night ? It might be remembered that he stated at one of the meetings the result of an excursion to Hampton Court, and gave a detailed list of the rare and valuable objects then obtained. He was quite sure that those members who brought home specimens were willing to share them with others. Announcements of meetings, &c, for the ensuing month were made, } Mr. F. Enock. 140 and the proceedings terminated with a conversazione, at which the following objects were exhibited : — Madreporiform tubercle of Uraster rubens... ... Mr. T.H. Buffham. Head and Tongue of Queen Wasp, Vespa rufa (prepared without pressure) Pupa of Indian plant bug ... ... ... ... Mr. H. E. Freeman Leaf of Hydroch avis ... ... ... ... ... Mr. W. H. Gilburt. Section of foot of Human Foetus... ... ... Mr. J. J. Hunter. Specimens of Corals in illustration of paper ... Dr. J. Matthews. Fossil teeth from Bristol Bone bed — Lyme Regis Mr. T. H. Powell. Peridermium columnare ... ... ... ... Mr. H. J. Roper. Fossil and recent Corals ... ... ... ... Mr. C. Stewart. Attendance — Members, 65 ; Visitors, 4. October 25th, 1878. — Ordinary Meeting. Professor Huxley, F.R.S., President, in the Chair. The minutes of the preceding meeting were read and confirmed. The following gentlemen were balloted for, and duly elected members of the Club:— The Rev. H. M. Clifford, M.A., Captain F. E. Dowler, and Mr. Wm. E. Howling. The following donations to the Club were announced : — " Proceedings of the Royal Society " ... ... from the Society. " Proceedings of the Bristol Natural History ) Society" ... ... ... i "Grevillea" ... ... ... ... ... ... Purchased. " American Journal of Microscopy " ... ... in Exchange. " Quarterly Journal of Microscopical Science " ... Purchased. " The Popular Science Review " ... ... ... from the Publisher. " Science Gossip" ... ... ... ... ... „ „ „ " The American Quarterly Journal of Microscopy " „ „ „ 3 Slides ,. Mr. A. D. Michael. Photograph of Mr. C. Le Pelly. The thanks of the meeting were unanimously voted to the donors. The President said that it gave him great pleasure on this, the first occasion upon which he had the honour to preside at one of their meetings, to be able to lay before the Socieiy a work which would contribute very much to the usefulness of the collections in their possession. It was a new and revised catalogue of the microscopical preparations in the Cabinet of the Society, and great praise was due to their Curator, Mr. Hailes, for the very efficient manner in which he had carried out this work ; the committee had expressed their sense of the value of this service by passing a vote of thanks to Mr. Hailes, and he would now ask the meeting to do the same. A cordial vote of thanks was then passed to Mr. Hailes for his services in the compilation of the new catalogue of slides. 141 Mr. Hailes thanked the members for the cordial way in which their thanks had been voted to him ; he had carried out the matter to the best of his ability, and hoped that the catalogue would be found useful. He had been asked to call the attention of the members to a new form of lamp and shade by Messrs. How, a specimen of which was placed upon the table. He thought they would remember that about ten years ago he had himself introduced the white porcelain shade, which had since become so popular. He expected and hoped that some one would be able to improve upon it, but up to the present' time no one seemed to have really done so. Now, how- ever, he found that Mr. Smith, at Messrs. How and Co.'s, had improved upon it, and had produced a very pretty and useful lamp ; it was smaller, and therefore more portable than the original one, and the shade being closed in at the top cut off the light there entirely. In reply to an enquiry as to its cost, Mr. Hailes said he was unable to state it, he had no interest in the manufacture, and could only refer to the makers. The thanks of the meeting were voted to Mr. Hailes for his com- munication. Mr. W. H. Gilburt read a paper " On the floral development of Helianthus annuus," the subject being illustrated by a number of diagrams. The President said that he had been paying great attention to the paper which they had just heard read, and he must confess that as he did so, it had occurred to his mind to complain of a deception which seemed to have been practised upon him by their Secretary. When he was asked to become their President, he was told that they were not a scientific society in the severe sense of the term, but that they were largely made up of the amateur element. All he could say now was, that if tltat paper did not satisfy Mr. Ingpen, he must be very hard indeed to please. For his own part he might say that having dabbled in many subjects in the course of his time, amongst other things he had paid some attention to plant development, as he thought that there was no more instructive com- mentary upon animal structure than that supplied by vegetable growth. Indeed, he might say that the more important conclusions arrived at by such workers as Wolff and others were based very largely upon the study of the development of plants. He could not help saying that he had never heard a better paper, nor one which he regarded as a better piece of work, nor one which had been thought out on more philosophical principles than the paper which they had heard that night. It was one which must especially be instructive to every botanist, and he had been very much struck with the amount of thought and care evinced in its preparation. The President having invited observations upon the paper, and meeting with no response, remarked that there were two classes of papers which furnished very little in the way of discussion, those that were too good, and those that were too bad ; it was the medium class of papers which afforded the best material for discussion. Mr. John Hunter read a paper " On the Queen Bee and her fertiliza- tion," illustrating the subject by reference to an elaborately illustrated Italian work on the bee, and by the exhibition of living bees. 142 The President said that the whole subject touched upon by Mr. Hunter was wonderfully interesting. He (Mr. Hunter) certainly appeared to be one of those privileged persons who could handle bees with impunity. The story ran that if a black queen were crossed with a Ligurian di'one then all the workers which were hatched from the eggs of that queen would have the Ligurian marks, but the drones would have all the characters of the black bee — perhaps Mr. Hunter could tell them if this were the case. Mr. Hunter said that when an English queen had been crossed by a Ligurian drone it had been thought that this distinction could be made out, but the Ligurian drones were often so imperfectly marked that the dis- tinction was sometimes doubtful. The drone was thought to partake of the character of the mother, but he believed the fact had never been satis- factorily proved. In answer to an enquiry. Mr. Hunter said that the queen never left her home except to mate, and then she always flew quite away, sometimes as much as four miles. A member enquired why it was that the drones were so numerous if the queens were so few in number ? Mr Hunter said it was no doubt in order that the chances of the queen meeting with a drone might be increased. The President said he had been asked to announce that a paper was wanted for the next meeting. In this practice he thought he saw another part of this curious deception which had been practised upon him. In other societies a great deal of trouble had to be taken to secure papers for the meetings, but here it seemed they had only to intimate that a paper was wanted in order to get what they desired. The President announced the engagements for the ensuing month, and the meeting terminated with the usual conversazione, at which the following objects were exhibited : — Section of seed of Hemlock Mr. P. W. Andrew. Adiantum cuneatum ... ... ... ... ... Mr. W. J. Brown. Anguinaria spatulata ... ... ... ... Mr. C. G. Dunning. Tongues of Sand Wasp and parasitic Bee, showing") all the organs of the mouth without distortion > Mr. F. Enock. or loss of colour ... ... ... ... ) Various Insect Dissections ... ... ... ... Mr. F. Fitch. Chcetoceros armatum from Ormsby... ... ... Mr. H. G. Glasspoole. Swan's feather, polarized ... ... Mr. W. Goodwin. Ovaries of Queen Bee ... ... ... ... Mr. John Hunter. Section of Upper Jaw of Mole, showing trans- ) ,...,!. Mr. J. J. Hunter, verse sections ot teeth ... ... ... ) Glyciphagus plumiger, showing plumous hairs,' which attain a greater development in this species than in any other acarus. Only one specimen has been previously found in England' Section of brain of Blatta orientalis, showing") ,.,.,,.«. r., mb ( Mr. E. T. Newton. distribution ot nerve fibres, cells, &c. ... ) Mr. A. D. Michael. 143 Melicerta ring ens ... Spirogyra nitida in conjugation ... Batrachospermum moniliforme Ferns from the Coal Measures Hornblende granite from Cleopatra's Needle. Transverse section of Stem of Jasminum nudi- fiorum Larva of Beetle (?) Mr. T. C. White. Attendance. — Members, 99 ; Visitors, 26. • II Mr. G. D. Plomer. } Mr. J. W. Eeid. } Mr. G, , Smith. "j Mr. H. F. Ward. November 8th, 1878. — Conversational Meeting. The following objects were exhibited: — Dermis of Sponge, Hymeniacidon caruncula,~\ showing porous membrane and irregular de- > Mr. T. H. Buffham. position of spicula ... ... ... j Moss from Tenby ... ... ... ... Mr. A. L. Corbett. Zoophite — Crista eburnea... ... ... ... Mr. C. E. Dunning. English Trap-door Spider — Atypus Sulzeri ... Mr. F. Enock. General Anatomy of the Drone-fly. showing") Mr. F. Fitch. r l nervous system and respiratory organs. Section of capitulum of Helianthus o.nnuus ... Mr. W. H. Gilburt. Rhabdonema arcuatum ... ... ... ... Mr. H. G. Glasspoole. Polyxenvs ... ... ... ... ... Mr. W. Goodwin. Conochilus volvox ... ... ... ... ... Mr. J. D. Hardy. Hoinzontal section of upper jaw of mole, polarised Mr. J. J. Hunter. Head of Sabella, mounted in fluid two years ago Mr. A. D. Michael. Section of twig of Clematis vitalba, double stained Mr. F. H. Ward. Attendance — Members, 50; visitors. 5. November 22nd, 1878. — Ordinary Meeting. Professor T. H. Huxley, F.R.S., President, in the Chair. The minutes of the preceding meeting were read and confirmed. The following gentlemen were balloted for, and elected Members of the Club:— Mr. Jas. W. Cafe, Mr. H. F. E. Drayton, and Mr. Ernest E. Sabel. The following donations to the Club were announced : — " Proceedings of the Natural History Society of" from the Society. Glasgow " ) J ' ' Proceedings of the Belgian Microscopical Society" ,, ,, " American Quarterly Journal of Microscopy ... in exchange. " Journal of the Royal Microscopical Society" ... from the Society. " Annals of Natural History " ... by purchase. " Schmidt's Atlas of the Diatomaceae " ... ... „ subscription. " Science Gossip " ... ... ... ... from the Publisher, I Mr. Henry Lee. 144 Models made by the late Rev. J. B. Reade, to illus- trate his theory of beaded structures ... Dredgings from Gal way Bay ... ... ... Col. O'Hara. Twenty-four Slides ... ... ... ... Mr. A. C. Cole. Ten Slides Mr. F. H. Ward. Two Slides ... ... ... ... ... Mr. H. G. Glasspoole. One Photograph for the Album — Mr. Badcock. The thanks of the Meeting were unanimously voted to the donors. Mr. Henry Lee said that as the new Catalogue of Slides was now issued, it struck him that the time would be an appropriate one for members to look it through, so as to see where there might be some hiatus which they were able to fill up. There were probably still many specimens required to complete some of the divisions which members might be able to supply, and he would suggest that they should look through the catalogue with that object in view. The President said that the subject which he wished to bring before them that evening was a sort of contrivance which he had recently adopted him- self, for the purpose of making dissections. They would all be aware that in a microscope to be used for delicate dissections, certain qualifications were absolutely essential. In the first place they must have perfect steadi- ness, the stand must be firmly and well supported, and be of sufficient strength and weight to bear the pressure put upon it without moving. Next it must be of convenient height, so that in working the hands might get a steady support ; it should fulfil these two conditions, and yet not be so large as to be clumsy. The next point was as to the lenses ; they should be of such a form as to give a maximum of power, and yet at the same time afford sufficient distance between them and the object to admit of needles being moved freely to an angle of 60° with the surface of the plate, because the efficiency of the needles obviously depended upon the angle at which they could be used, and if a lens were made with a wide face it would very often interfere with the movements of the needles. Then there was another point of still greater importance — when a careful dissection had been made, it often became desirable to examine it with a much higher power than the one which had served the purpose of preparation, and provision ought to be made to enable as high a power as was desired to be brought to bear with- out disturbing the object, and this could only be done by placing a com- pound body above the simple lens. The President then exhibited the in- strument which he had devised to meet these requirements, and pointed out that it consisted of a glass stage, having a large aperture in the centre, and mounted horizontally upon three supports, one of which was formed by the pillar of the body; in this way it stood with great steadiness, and was strong enough to bear considerable pressure. The lens was carried by an arm projecting from the pillar, and made to turn aside horizontally when required; focussing and illumination were managed in the usual way, but there was a slow motion in addition to the rackwork. In offering the in- strument for discussion, the question would arise as to the best form of lens 145 to be employed, and he hoped to receive the opinions of the members npon this and other matters ; bnt at present he used an ordinary low-power achro- matic objective, made so as to slip into the arm without screwing; there was great convenience in thus mounting and using a simple lens. With the old doublet there was much difficulty in working comfortably, and whether a person could do so or not depended a good deal upon his nose, being specially troublesome in the case of those persons who had somewhat aspir- ing noses. In addition to the lens which he had placed upon the instrument, there was another belonging to it of half the focal length. Now, supposing they had made their dissection successfully, the point was how to be able to convert the instrument at once into a compound microscope without disturb- ing either the lens or the object. One of his aims in life had been to get microscope makers to abolish screws, which he regarded altogether as abominable inventions, and in this instance, the compound body had been made to slip over the outside of the socket in which the objective had been placed. This plan answered fairly well, but he thought it would be better to have it made to fit rather more easily, and to be secured by a bayonet joint, because, supposing that the power employed was not sufficient for the purpose, then inconvenience arose unless the body could be got off again with sufficient ease to ensure the object remaining undisturbed by any jerk or movement. With the improvement of the bayonet joint, it would be easy to remove the body, and having taken out the first lens and dropped jn, say a one-eighth in., the body would go on again without any disturb- ance. He had the instrument before them made upon that pattern, to see how the thing would work ; he had used it for the past six or eight months incessantly, and could certainly say that for his requirements it was the best thing he had seen, and he believed that with the little addition of a bayonet joint it would be as nearly perfect as any instrument of the kind could well be. He thought that all persons who had been occupied in mak- ing minute dissections would see that it had value, and met all the require- ments of the most delicate work. He hoped that the members would examine and criticise it, and make any suggestions that occurred to them for its further improvement, for it was becoming of very great importance to examine thin sections and minute portions of dissections without sub- jecting them to any such disturbance as to cause the slightest alteration, and it was equally important to be able to bring to bear upon them under such conditions the highest powers that might be needed. Dr. Matthews enquired if the President spoke of dissecting in water ? The President said that he referred to dissection in a very shallow trough, and by transmitted light. Mr. Ingpen was sure that the members would feel highly indebted to their President for bringing this instrument before them. The question of dissecting microscopes had always been a difficult one, from the different requirements of various individuals, and in many cases there was too great a desire for cheapness. He added some remarks upon the best form of slow motion, and on the objectives most suitable for the purpose, and then called attention to a number of dissecting microscopes which had been in use at 146 various periods, and which had been kindly lent for the occasion by Messrs. Crisp, Swiffc, Crouch and Curties. - Amongst these were the well-known " Quekett "' dissecting stand, the Lawson Binocular was also interesting as an attempt to introduce the binocular principle ; a very old one, lent by Mr. Curties, had the lens connected with the base by a number of short tubes with ball and socket joints; a large one made of wood, with a glass stage, was well known to their President (who said somebody had called it a " beetle trap"), it was very simple, and owed its origin to the Leoni form ; two other forms were those devised by the late Andrew Ross ; and one by Mr Swift was a sort of brass transcript of the original Quekett instrument, the stand of which was made of wood. Mr. Crouch said the instruments on the table well illustrated .the diffi- culties which microscope makers had to contend with in the matter of dis- secting microscopes, for no two persons seemed to agree as to what they really wanted. As a rule, an optician was required to make a certain in- strument to fulfil certain purposes, and was requested to make it for not more than £2 or £3, and for every dozen persons he would have to make two dozen alterations in the pattern. As far as the objectives went, there was not the slightest difficulty in making what had been mentioned ; but until they could get observers to agree as to what they wanted, it would not be worth any optician's while to take up the subject. Mr. Ingpen said that the question of cost depended very much upon where they went to get the thing made. The Eoss dissecting microscopes cost, he believed, A\ guineas, and with the doublets and accessories, it soon ran up to £10. The President said he had one of that pattern about 30 years old, and believed that it cost the sum named. Dr. Matthews enquired if the President had ever employed a binocular eyepiece for dissecting purposes ? The President said he must confess that he was rather heretical as to binoculars in such cases. What was really wanted was to have the object well lighted and well defined. For all ordinary purposes there was nothing better than a good watchmaker's eyeglass, because it was so readily adjusted to the work, and, with a good orbicularis, to keep it in its place, there was no trouble in using it. Dr. Matthews explained that he meant the ordinary binocular eyepiece, and not the binocular microscope. Some persons had a difficulty in holding an eyeglass properly, and to meet such cases there was another plan for nsing a single lens, namely mounting it upon an elastic wire, which could be moved to or from the object as required, by the pressure of the head. The President said that there was sometimes a little difficulty about hold- ing the glass in the eye at first. When a person was beginning to do so, he was apt to indulge in a good deal of impatient ejaculation ; because, when he got absorbed in his work, he forgot the eyeglass, and let it drop occa- sionally into the middle of his dissection. Mr. Ingpen thought that a large spot lens would be found of value, so as to get a black ground for the illumination of delicate transparent tissues in 147 water, especially as it would not exhibit the disturbance of the surface of the water by the needles. The President said that he generally used a black screen for the latter purpose. There was one other point upon which he should like to have the opinion of the Club, and that was upon the best way of illuminating things whilst working by daylight. He could not get on very well with the con- densing lens, and found it rather troublesome ; reflected light seemed to be the best, and he had often wondered if a polished hollow cone would be a good sort of thing to use. Dr. Matthews said that the idea had occurred to him of adapting some- thing like the " speculum, uteri " to the purpose, which would resemble a Wenham's illuminator inverted. He thought it would answer very well with a lens inserted into the wide end; he was, in fact, on the point of having one made, to try. Mr. Charles Stewart was sorry to say that he must differ somewhat from their President as to the valne of the binocular microscope in dissecting, for he had found it of the greatest use in the case of transparent objects, since it enabled him to recognise the precise position of one object above or below another, with a facility which he thought was of the greatest importance. He also wished to bring before them a little matter which he thought might be of interest, as it was in some degree connected with the subject which had engaged their attention. In making minute insect dissections, he had often f onnd the want of a perfectly structureless background upon which to pin the object, and upon which it might be treated with spirit, and set aside to work npon at leisure. He had tried various things, but at length Mr. Field, of the Ozokerit Works, gave him a small quantity of black Ozokerit (or black wax as they called it), and this seemed to answer admirably, for it melted at a low temperature, remained soft enough to stick a pin into, and was absolutely unacted upon by strong alcohol, or water, or by any mixture of them. When required for use it was only necessary to put a few knobs of it in a saucer, and when it was warmed it flattened out over the bottom with as smooth a surface as could he desired. There were two sorts of it, one being a little harder than the other — he had brought some speci- mens of each with him to the meeting, both in the lump and run out in small saucers ; the rims of these little saucers being ground off flat, a glass cover could be laid over them, and the contents would be preserved from dust, and, in a great measure, from evaporation also. One very great ad- vantage about this stuff was, that there was no stain to come out of it; if gutta percha was used, the spirit extracted a kind of gummy product from it, a stain came out of it, and it very soon became brittle, whilst even the best cork contained numerous small cells, which got out after a time, and seemed to have a peculiar proclivity for attaching themselves to the most delicate nerves and filaments. The new substance seemed to him to fill a want, and it was equally useful for large dissections, as it could be made to line a trough with very little trouble. The President said it struck him that the idea of using this material was a very important suggestion, and he could see at once that, in comparison 148 with it, gutta percha and cork were hopelessly out of court. He had him- self used paraffin or wax. It was certainly a great advantage to have it black, as attempts to blacken paraffin generally resulted in getting some por- tions of the surface well coated, but others not covered at all. Then again as to pins ; he thought a great deal of the fact that pins would stick into it so well j with paraffin the sides of the hole did not seem to close upon the pin as they ought to do, and so a very slight tension disturbed it, and by- and-by the pin became loose, and then the dissection became disturbed. With this new wax it was not so, there was a sort of elasticity about it which caused it to shut upon the pin and enabled it to bear the strain. He should also be glad to know where these convenient little saucers, shown by Mr. Stewart, were to be obtained ? Mr. Stewart said they were to be found at the corners of the streets, containing three whelks or three mussels for a penny. He bought those he had brought to the meeting at a shop in the New Cut, where they were supplied to costermongers. Dr. Matthews said he had used heel-ball, such as was used for taking rubbings of bi'asses with ; when this was melted it answered very well. Mr. Stewart rather fancied that there was rosin in the heel-ball, and if so, they could not use it in contact with spirit. Mr. Thos. Spencer said that such was the case. Dr. Matthews said he mentioned it because in case of failure to get the ozokerit, the heel-ball would be found a good substitute, though, of course, it would only do for use with water. Mr. T. C White enquired whether a supply of this substance could be got by members of the Club, and at what cost? Mr. Stewart said he thought it was worth about lOd. or Is. a pound; he had not the slightest doubt bat that it could readily be obtained if required, especially as Mr. Field was himself a scientific man. " Black wax " was the name they called it at the works. It was soluble to some extent in benzine or turpentine. Mr. Hailes said it was a substance very well known now in commerce. It was a kind of native or mineral wax, and was found in Bohemia in large quantities, and now that it could be bleached it was used very largely for making candles. It was found in lumps, and was melted and run into casks for exportation. Mr. Thos. Spencer thought that if the material itself was subjected to a bleaching process, possibly this black stuff might be some kind of residuum. Mr. Pearson believed that there were some specimens of it, in its native condition, at the Geological Museum in Jermyn Street, and if he remem- bered rightly, they were of a very dark brown colour. Mr. lngpen had very little doubt that since the value of this substance for microscopical purposes had been so prominently pointed out, the opticians would soon be able to supply it to those who wanted any. As regarded the best methods of illumination, condensers were by no means so good as reflectors, especially by daylight, when the concave mirror belonging 149 to the microscope would form a very good illuminator for opaque objects. For those persons who could not comfortably use the binocular dissecting microscope, he should recommend the use of a large spot lens as an illuminator, which they would find of great use in showing the relative positions of the various portions of a semi-transparent substance viewed by transmitted light. The President having proposed a vote of thanks to those gentlemen who had so kindly sent specimens of dissecting microscopes that evening in illustration of the subject they had before them, it was put to the meeting, and carried unanimously. Dr. Matthews said he was rather taken by surprise at the proceedings having terminated so abruptly, but rose to do what he had intended to have done earlier, namely, to propose a hearty vote of thanks to their President for the very interesting communication which they had heard that evening. The motion was put to the meeting, and carried by acclamation. The President made the usual announcement of meetings, &c, and the proceedings closed with a conversazione, at which the following objects were exhibited : — Seeds of Epipactis latifolia, showing loose reti- •) m , « ,, , , . i ? Mr. C. Emery, culate testa, and minute embryo ... J Head of Nbmada Uneola, a parasitic Bee, prepared without pressure, showing all the parts of the mouth, without distortion or loss of j ' * natural colour ... ... ... ... J Tip of Blow-fly's tongue showing the teeth in relief Mr. F. Fitch. Macrospores or spore-cases (?) from coal Rev. T. W. Freckleton. Section of capitulum of Helianthus annuus, showing development of ovule ... Cuticle of Maize, polarised ... ... ... Mr. C. Le Pelley. Lissajous' Curves, ruled microscopically on glass, i showing apparent solidity of figure ... j ... y Ear of Lobster, showing otoliths, filaments, -\ and auditory nerve ... ... ... r Mr. J. Slade. Nicothce, an epizoon from gills of Lobster ... J Ruse us aculeatus, Butcher's Broom, section of stem Mr. F. H. Ward. Attendance — Members, 91 ; Visitors, 9. X Mr. W. H. Gilburt. 150 On a New Method of Preparing a Dissected Model op an Insect's Brain from Microscopic Sections. By E. T. Newton, F.G.S. (Read January 2-1, 1879.) The structure of the nervous centres of Invertebrate Animals is a subject which is attracting some attention at the present time, and I have myself been much interested in the study of the Insect's Brain ; but have found some difficulty in clearly compreliending the forms of certain of the internal parts. In order to get a better knowledge of these forms, I was led to construct a model, on a principle which I believe to be entirely new. Knowing the interest which our honoured president and the members of this Club always take in new methods of working, I felt constrained to bring the matter before you, and it is the purpose of the present paper to describe the manner in which this model has been constructed. Whether the method will prove available for other objects, time alone will show. It will, perhaps, be desirable, before commencing the description, for us to call to mind the general form of an insect's brain. Some of us endeavoured on our last " Gossip niglit" to get a general knowledge of the anatomy of an insect, and, with regard to the nervous system, we noticed, that the most anterior pair of ganglia, which is placed in the fore part of the head, is joined by two large commissures to the second pair, which is placed lower clown, and towards the back part of the head. Through the ring thus formed the gullet, or oesophagus passes, and hence the anterior ganglia, being above, are termed the supra-cesophageal ganglia, and the second being below, are called the inJra-cesopJwgeal ganglia. The positions of these parts is very well shown in the diagram of these ganglia, taken from a Mole-cricket (Fig. 1). The upper ganglia present two rounded prominences above, from the sides of which the optic nerves are given off (op), while at the top are seen two ocelli. Somewhat lower down, and towards the front, are two other prominences, from which the autennary nerves pass off (an). A little lower down a nerve is given off from each side, the two joining in the middle line to form the frontal ganglion [f g.) ; from this a single nerve passes E. T. NEWTON ON PREPARING A MODEL OF AN INSECT^ BRAIN. 151 backwards along the upper surface of the alimentary canal. Below and behind the large commissures (cm) pass to the lower ganglia (lb), and, being long in the Mole-cricket, the two pairs of ganglia are well separated. In some insects they are much closer together. FIG. 1. — Brain of Mole-cricket, after Dietl. — ub, upper division of the brain, or supra-oesophageal ganglia ; lb, lower division of brain, or in- fra oesophageal ganglia; cm, commissures between upper and lower divi- sions of brain; x, a cross-band of fibres peculiar to mole-cricket and some other insects; an, antennaiy nerve ; op, optic ganglion; o, ocelli ; fg, frontal ganglion of stomato-gastric nerve ; 1, 2, 3, nerves to mouth organs. From the lower pair of ganglia the nerves are given off which supply the mouth appendages. The researches of Faivre, in 1857 (" Du Cerveaux des Dytisque dans ses rapports avec la locomotion." " Ann. d. Sci. Naturelles. Zool." tome 8, p. 245) seem to show that the power of co-ordinating the movements of the body is lodged in the infra-cesophageal ganglia, and, therefore, it is not without reason that some authors regard these as a part of the brain. What follows in this communication refers only to the supra-cesophageal ganglia, or, as I should prefer to call them, the upper division of the brain. The general arrangement of the internal structures will, perhaps, be best understood by reference to the figure given by Leydig, of the brain of Formica rufa (Fig. 2.) ("Tafeln zur Vergleichenden Anatomie," 1864, t. 8, fig. 4). Upon each side there is a large central ovoid mass (pi), which has been termed, the primary lobe, and this abuts in the middle line upon its fellow of the opposite side, while the optic nerve, with its ganglion (op), is given off from 152 T. NEWTON ON PREPARING A the outer or opposite end. The optic ganglion itself is a very complex structure. The antennary lobes (al) consist of a number of large rounded masses, -which have been called cells, but are really made up of a network of fine fibres. Above the primary lobe are seen the peculiar bodies, having the appearance of half-rings (mb), which have been called convolutions, by Dujardin. (" Sur le systemenerveauxdes Insectes," 1850. " Ann. Sci. Naturelles. Zool." ser. 3, tome xiv., p. 195), and have been compared to mushrooms. FIG. 2. — Brain of Formica rufa, adapted from Leydig. — pi primary lobe ; al, antennary lobe ; an, nerve to antenna ; op, optic ganglion; fe, facetted eye; o, ocelli; mb, mushroom-bodies ; st, stems of mushroom-bodies; c, cap of cells covering the mushroom-bodies; ma, optical section of the anterior mass of nervous matter. Each of these mushroom-bodies is supported upon a stem (si) which passes downwards into the primary lobe, where the two lie close to each other, if they do not join. The exact form of these mushroom-bodies is not easy to be made out from preparations such as that figured by Leydig, and, indeed, the appearance presented by sections does not convey a very clear idea of their form. In the middle of the primary lobe, as figured by Leydig, there is a rounded mass, which he describes as a " giant nucleus " (ma), but more recent researches have shown that Leydig was mistaken, and that this appearance is really the optical section of a cylinder of DISSECTED MODEL OF AN INSECT'S BRAIN. 153 nervous matter, which passes forwards, to end abruptly upon the front surface of the brain. The structure was correctly described by Dujardin, in 1850, but does not seem to have been recognised by Leydig ; this was, no doubt, due to the method of investigation em- ployed by the latter, which consisted in clarifying the brain (pre- viously hardened in alcohol) in potash solution, or glycerine. With regard to the origin of the nerves of the ocelli (o), it is desirable that Leydig's figure should be verified, for it seems very improbable that they should arise from the heads of the mushroom- bodies in the Ant, and from a different part of the brain in other insects.* Insects' brains vary very considerably as regards the development of the mushroom-bodies. In Ants, Bees, and Wasps they are proportionately large, and double on each side. In the Cockroach they are double, and moderately well developed, and in the Mole- cricket there is said to be only one on each side. Dujardin could not detect these mushroom-bodies in the Diptera ; but recent investiga- tions (E. Berger, " Untersuchungen iiber den Bau des Gehirns und der Retina der Arthropoden." Arbeiten des zoolog. Instituts zu Wein. Bd. I., Heft. II., p. 173) show that certain bodies exist in the Blow-fly (AJusca vomitoria), and the House-fly (31. domestica), which, most probably, are correctly regarded as the homologues of the mushroom-bodies. I had already prepared sections of the heads of several insects, some of which have been exhibited at our meetings, before I saw the paper by Dr. Dietl (" Zeitsch. f. wissenschaft. Zool." 1876, vol. 27, p. 488), in which some beautiful sections of Insect brains are figured and described. When I saw them I determined to try the method he had used for hardening the brains, namely, with hyperosmic acid. The insect which I selected to work upon was the Cockroach (Blatta orientcdis). In the first place it was necessary to remove the brain from the head in a perfectly fresh condition, and this required some care, because the organ itself is extremely delicate, and if the investing membrane be injured the internal parts are apt to be squeezed out in the hardening process. The fresh brain, cleared from the surrounding parts, was placed for a few hours (6 or 8) in an aqueous solution of hyperosmic acid (£ to ± per cent.) It was then * I find, since this paper was written, that according to Flogel, these nerves pass down beside the mushroom-bodies to the middle of the brain. (" Zeitsch. f. wissenschaft Zool.," 1878, Vol. 30., suppl. p. 556.) M 154 E. T. NEWTON ON PREPARING A washed and laid in spirits of wine. The hyperosmic acid seems to me to be somewhat uncertain in its action, for sometimes the brains remained soft and unstained in the interior, while at other times the hardening and staining was most successful throughout. The next point was to cut up the brain in a definite direction into consecutive sections of a known thickness. So much has been said in this Club lately about section cutting, that it would only be wearisome to attempt to describe the process fully. It may, however, be mentioned that a microtome was used, in which the screw for raising the object was divided, so as to register a thickness of about the T oVtt °f an inch. The brain was embedded in wax, in the usual manner, and each slice, as it was cut off, was placed directly upon a glass slip in a drop of glycerine, and numbered. When the entire brain had been disposed of in this way, the sections were cleared of the pieces of wax adhering to them, covered with thin glass, and cemented down. The sections which appear to me the most instructive are those cut in a direction as nearly as possible parallel to the front of the brain. One brain, cut in this direction, gave me 34 slices, each about the yoVo- of an inch thick, and as no intermediate pieces were lost — although some were subsequently injured in the process of mount- ing — I had the whole of this upper division of the brain in a con- secutive series of slices, and, therefore, in a very satisfactory condi- tion for work. Any one who, in working out structures by means of sections, has endeavoured to trace the various parts through a series of slices, will understand how difficult it is to keep in mind the structures seen in each, so as to picture to himself the form of any part when entire. And still more difficult is it to convey to others the knowledge which one has gained by the examination of such a series. Now it seemed to me that, if a drawing of each section of the series were made, and the corresponding portions in each coloured some definite tint, then the structures presented would be much more easily understood, inasmuch as they could all be laid before the eye at one time. I determined, therefore, to prepare such a series of drawings with the camera lucida, and the diagrams numbered 2, 4, 6, 10, 13, 17, 20, 25 (Fig. 3), represent the most typical sections of this series ; only one-half of each section being here represented. In section No. 2 may be seen, at the lower part, a portion of the antennary lobe (al). In the middle is a mass of nervous matter, here distinguished by vertical lines, and marked (a). Above this is a DISSECTED MODEL OF AN INSECT S BRAIN. 155 cap-like portion, distinguished by horizontal lines (c). These are the portions which should be borne in mind in passing through the series. Os CL—&- 'i rrvb FIG. 3. — Diagrammatic) outlines of sections of the upper part of the brain of a Cockroach. Only one side of the brain is here represented. The numbers indicate the position in the series of 34 sections into which this brain was cut. inb, mushroom-bodies, with their cellular covering, c, and their stems, st; a, anterior nervous mass; m, median nervous mass. 156 E. T. NEWTON ON PREPARING A In No. 4 we find that while the parts noticed in No. 2 remain much the same, two dark masses (mb) have appeared in the upper portion, close to the mass (a), but definitely separated from it. In No. 6 the dark masses have increased in size and become somewhat curved, but the most obvious difference is that the mass (a) has suddenly extended inwards and downwards to the middle line of the brain (in). In No. 10 the dark masses are much more deeply curved, the upper portion of the mass (a) is rather less, and another process has begun to extend upwards and outwards (st). In No. 13 the most important point to notice is that, while the inner mass (a) has almost disappeared, the outer one (st) has extended upwards, and may be seen to join the outer dark mass. In the 14th section the outer mass (st) joins the inner dark mass also, and this junction extends as far as the 18th or 19th section. In No. 17 the outer mass (st) may be seen joining both the dark masses, which are here very deeply hollowed out. In No. 120 the outer mass has entirely disappeared, and we have simply a small portion of the lower mass (?n) left close to the middle line, the dark masses are somewhat smaller. The extension (coin) seen just below the antennary lobe is the commencement of the com- missure to the lower division of the brain. In the sections which follow, all the parts above-mentioned, excepting the commissure (com), get gradually less, and the dark ones are seen, for the last time, in section No. 25. The median portion (in), however, may be traced to the 28th section. The next step in the process was this : It occurred to me that, if the card, upon which these outlines were made, were of a thickness proportionate to the enlargement of the drawings, and if each were cut out, and the whole piled together, one ought to have a model of the exterior of the brain. I set to work, therefore, to do this, but in order to lessen the labour as much as possible, it being merely an experiment, it seemed desirable to make one half first, and instead of making models of the whole series, the thickness of each slice was doubled, so that it was only necessary to make 17, taking, as a pattern, every alternate drawing. The material used was soft pine-wood, each piece being about the ith of an inch in ftiickness. Having cut out each model slice with o a fine saw, the whole were piled together in their relative places and temporarily fixed, so that the corners might be trimmed off, and the result was the form which is seen in the model of one-half of the DISSECTED MODEL OF AN INSECT S BRAIN. 157 upper brain (Fig. 4). The different slices, however, were not left fixed together, but were separated and arranged so that they might be taken to pieces, as in the process of cutting sections, and the surfaces thus exposed were coloured to represent the sections as they appear under the microscope. an- Oj} CV-- 111 - — conv- —c —-71lt —§b coin FIG. 4. — View from the outer side of the left half of model of upper part of brain of Cockroach. The oblique lines in this and Fig. 5 indicate the successive slices of which each is composed. Op, cut end of optic nerve ; an, cut end of antennary nerve. FIG. 5. — Eight-half of model -brain seen from the inner side, with the parts dissected away, so as to show, the anterior nervous mass, a ; the median mass, m ; the mushroom-bodies, nib; and their stems (st). The cellular cap, c, has been raised, so as to display the parts below ; com, is a part of the commissure to the lower portion of brain, or infra-oesophageal ganglia. This method of modelling was capable of still further develop- ment. Having modelled the opposite half of the brain upon the same plan, I drew upon each of the model sections, thus produced, the outlines of the more important parts, as shown in the diagrams (Fig. 3), and these were then cut out in the same manner as a child's dissected map-puzzle. Now it will be obvious that by taking from each of these " dissected " sections, the part, for instance, which is in the diagrams (Fig. 3), marked (c), and joining them together in their relative places, we shall have a model of that par- ticular part ; and by joining, in like manner, the dark masses, and 158 E. T. NEWTON ON PREPARING A MODEL OF AN INSECT'S BRAIN. those marked (a), (m), (st), we shall obtain models of the mushroom- bodies, with their stems, &c. In this manner the dissected portions of this side of the brain were joined together, and, after some little trouble in adjustment, one was enabled to make the parts fit together in their relative places. We have now, therefore, upon the left side, a model which may, so to speak, be cut up in slices, to show the microscopic appearance of the sections (Fig. 4), and on the right side, a model of the more important internal structures, which may, as it were, be dissected out before a class of students (Fig. 5). I was in hopes that, before reading this paper, I should have been able to coustruct a similar model of the Brain of a Bee, in order to verify the descriptions of Dujardin, Dietl, and others, who have worked at this insect, but have not yet had the opportunity. This, I may say, however, that an examination of this model goes far to prove the correctness of their descriptions, for we see here a mass of nervous matter ending abruptly on the front surface of the brain, this extending backwards, and being joined by the stems of the mushroom-bodies, and reaching nearly to the back of the brain, after being gradually reduced in size. The heads of the mushrooms are seen to be, as described originally by Dujardin, discs folded upon themselves, and bent downwards before and behind. No doubt the forms of these parts differ in the Bee and the Blatta, but still, in their principal features, they are much alike. I cannot help thinking that, a model such as this gives a far better idea of the true form of the internal parts, than it is possible to obtain from a study of sections alone, and, indeed, even if these minute structures are dissected out, there is great fear of their being distorted in the process. But, after all, the great use of such models is to enable the lecturer, or demonstrator, to convey to his students a correct knowledge of the parts under consideration, and I trust that this model may be the means of enabling some of us to comprehend, more easily than we otherwise should, the complex structures of an Insects' Brain. 159 On the Urticating Threads of Actinia parasitica. By Francis Alfred Bedwell, M.A., F.R.M.S. {Read January 24th, 1879.) Plate X. The line of the Dorsetshire coast near Swanage, magnificently iron-bound though it is to the westward, nevertheless affords from Durlstone Head eastward and northward, to Studland Bay, a fair hunting ground for seaside study. When I first saw an urticating thread it was at Durlstone Head. I was seeking micro- scopical objects there, when a small pool attracted my attention ; it displayed a score or more of white filaments, which radiated to every point of the compass, from some central object that lay concealed at the bottom of the pool. I had no sooner seen them than the first returning wave of the flood tide filled the pool and obliterated the sight ; it puzzled me exceedingly at the time, as I was quite ignorant of its meaning, but, as I found out soon afterwards, the filaments were the urticating threads (Acontia, Gosse) of Actinia parasitica. This actinia, as is well known, attaches itself to the whelk shell, which the hermit crab inhabits, and it is carried by the crab into the lobster pots, which are laid in deep water along that coast. It is not remarkable for that outward splendour which makes some of these creatures such delightful studies externally ; but it has some excellent qualities recommending it to the student ; one is that it rarely keeps its beautiful disc closed for long, while it carries about 50 of these threads ; and they are organs of extraordinary interest. A thread varies from ten to four inches in length — fine as very fine sewing thread, and yet strong enough singly to bear the weight of actinia, crab and shell, and draw them up to the surface of the water without break- ing ; the threads are greasy to the touch, and ooze through the fingers, however tightly held. If a piece is cut off and examined under the microscope, it is seen to be literally a crowded mass of elliptical cap- sules, all set with the long axis radiating to a central longitudinal axis, so as to give (as I suppose) an imaginary transverse section N 160 F. A. BEDWELL ON THE URTICATING THREADS OF as seen in Plate X., fig. 1. The thread is very richly ciliated, and even when severed from the animal, still it moves — in graceful curves — here and there — stealthily returning on itself, but never at rest. Sometimes it makes a perfect coil like the ropes on a man-of-war's deck, and quite as truly laid ; but its favourite attitude is seen in fig. 2, and is that of a perfectly regular spiral ribbon. I had been watching its movements one evening for some consider- able time in wonder at its function, and amazement at its beauty, when I was enlightened in a moment as to what it was and what it could do. In the small glass slide with it was a lively little annelid, making its perpetual figures of S — first this way and then that. In an unlucky moment it touched the coil. Now its gyrations had been lively before, but the touch made them frantic — and there was cause — for from out the thread there flew at the worm a blinding mass of cap- sules, each with a short thread projecting from it, and the whole accompanied by a sticky fluid. See fig. 3. The writhings of the worm only brought it into fresh contact with the thread, and each contact served only to bring out a fresh supply of capsules and fluid, while some of the former stabbed the worm in the characteristic manner ; and even if the worm could have escaped from its murderous opponent, it would but have carried with it a viscous web of capsules and slimy fluid, so fine and delicate, and yet so tenacious and com- pact, that no mere exertions of the animal would probably have relieved it from the terrible net. That the animal was "stung" (to use the only word which will express its gestures) I have but little doubt, and although the character of its movements and of its very efforts to escape actually placed it at a great disadvantage in this extraordinary contest, still it was not paralysed. I released it from the thread, and it was none the worse, except that it was stabbed here and there by capsules. The second encounter that I witnessed was of a still more terrible nature. Close beside the coil there was a small organism, with a molluscous like tail, that oozed along the glass just as a snail or amoeba moves. See fig. 4. Its length was about a quarter of an inch. The progress of this adventurous animal took it straight over the coil, and with its soft tail it oozed transversely on to the thread. It was really painful to see what followed. Not a cajDsule disturbed itself, and yet the worm simply went to pieces ; it was torn to fragments, entirely disintegrated, while the coil softly moved onwards, disarranged in no way whatever. ACTINIA PARASITICA. 161 But a third instance was even more remarkable still ; it was the case of an annelid, about three-quarters of an inch long. See fig. 5. Its head is represented in fig. 6. The coil gently passed over the lower rings of the worm's body. The eye could distinguish the glisten of the ciliary apparatus as it seemed deceitfully to woo the body of the worm, and the worm moved on wholly unaffected by the contact ; but at last the thread reached the head, and brushed that, and the worm then and there died. Not a capsule left the thread, yet the worm was killed. I removed it from the water, but it hung lifeless at the end of the forceps. There was but one worm of those I saw attacked (if it can be called a worm) which was armour proof against this deadly foe, it was one which I have endeavoured to draw at fig. 7. It was about three-quarters of an inch long, and covered all over with cilia, and seemed to meet brush with brush, and it passed by and over the coil with perfect indifference. Now the attitude of the thread in fig. 2 has no doubt suggested to the reader one, at least, of the uses which we may attribute to it, and the above facts, taken together, certainly, I think, bear out the idea that the thread is a fishing line — it destroys and it gathers in. If an animal protests against the contact, it is caught in a confining web of bewildering capsules and a maze of viscous fluid, which keeps it a close prisoner beside the thread, to be drawn in with the thread at the will of the actinia. If it remains quiescent it dies, either torn to pieces or paralysed. The thread of the screw acts as a ditch or duct, and the ciliary action sets up a strong tide of particles along it ; but for the accidental and fortunate circumstance, how- ever, that I had seen the threads radiating in the pool at Durlstone Head, as already described, I should have hesitated to give this character to the organ, but that incident satisfies me that * at times, at any rate, its functions are those now attributed to it. The whole story of this Actinia is a most astonishing one — the fact that it takes to a carriage at all, the fact that it and the crab also must change carriages from time to time, as each successive shell proves too small for them ; the instinct that makes it always leave the open- ing of the whelk shell uncovered for the crab ; its possession and use of the acontia ; the story told by Mr. Gosse* of the parasitica * " Actinologia Brit.," 115. 1G2 F. A. BEDWELL ON THE URTICATING THREADS OF which found out the favourite haunt of the hermit crab in an aquarium, and waited its opportunity to slide off the rockwork on to his shell, are some of the instances of its extraordinary habits and gifts. But I became acquainted in 1868, at Swanage, with an in- cident connected with this crab and actinia, which may be of interest. I noticed that when fresh specimens were put into an aquarium the pair soon parted company, and the following morning the hermit crab would usually be found to be dead, with a wound in its side. On look- ing round for the enemy that had assailed him I found that most of the shells actually had a third inmate, in the form of a large worm (see fig. 8), which, with a most ferocious pair of jaws concealed in its body, had killed the crab. As to which of the triumvirate (if either) destroyed the whelk in the first instance, I do not pretend to say, but I strongly suspect one of the three did it ; perhaps not the actinia, as I have seen parasitica very contentedly riding on a shell with the whelk itself inside ; but, at any rate, here are three animals living in or on a house they never made, the crab dragging for all and digging for all, and the actinia, by the help of its fishing lines, picking up from the diggings of the crab the annelids, amoeba, etc., that he disturbs, the worm (fig. 8) living on the leavings of the actinia, and then winding up the scene by eating into the crab, because he does not move fast enough, or because food gets scarce in a contracted aquarium ! I agree with Mr. Gosse that the threads are weapons of offence and defence, as the Actinia ejects them on irritation ; but there is this curious circumstance about them, that at last the animal gets accustomed to being touched, and will not eject them. And after a very little time, when I wanted to obtain a piece of thread for ex- amination, I had to insert a crochet needle gently into the oval aperture and fish up one for myself. At first the animal resented this intrusion, and closed its disc, but it soon became accustomed to that also, and latterly never stirred when I introduced the needle. Undoubtedly the threads must assist digestion, even when within the body, by destroying and disintegrating the small living objects which are brought into the inner chambers by the constant currents to be seen passing in and out of the two little gristly-looking angles or channels (gonidia, Gosse), situate one at one corner of the oval aperture and the other at the other, and which are usually kept open, however closely the stomach walls may have come together and closed up the oval aperture. ACTINIA PARASITICA. 163 Mr. Gosse says* that in form the thread is a flat narrow ribbon. I have never seen it in an attitude which gave me an impression of flatness. To my eye, it was usually cylindrical with a heart-shaped transverse section, and a cleft running along it longitudinally, and so I prefer to draw it. The attitude of the thread (fig. 2), indeed, gives, as I have said, the effect of a coiled up ribbon. I must, in conclusion, apologise for the unscientific character of the language employed in this communication. I know how unsatisfactory this must be to scientific readers, but I have thought it best not to affect to adopt phrases or attempt a style with the use of which, per- sonally, I am hardly if at all familiar. DESCRIPTION OF PLATE X. Fig. 1. — Transverse diagrammatic imaginary section of nrticating thread (acontia) of Actinia parasitica X 100. Fig. 2. — Favourite attitude of same thread X 40. There is a regular set of particles along the screw line. Fig. 3. — Annelid (or Turbellaria ?) entangled in capsules and viscous fluid, discharged from thread (see text), X 8 j size of capsules exaggerated. Fig. 4. — Annelid (or Turbellaria ?), with soft molluscous-like tail, des- troyed by thread (see text), X 16. Fig. 5. — Nereida (?), destroyed by thread (see text), X 2\. Fig. 6.— Head of ditto, X 10. Fig. 7. — Unknown organism unaffected by thread, X 3. Fig. 8. — Nereis (?) found in whelk shell with Hermit Crab and A. parasitica, X \. * <( Actinologia Brit.," p. xxv. 164 On The Rotifers, by Dark Field Illumination. By C. T. Hudson, M.A., LL.D., &c. At the ordinary meeting, on February 28th, Dr. Hudson exhibited, in the Mathematical Theatre of University College, a large number of very beautiful transparent drawings, . which being strongly illuminated from behind by lamps placed in a closed box, gave most faithful representations of the various rotifers as they appear under the microscope when illuminated with the paraboloid. The drawings were fully described, and the following is an abstract of Dr. Hudson's remarks. Dr. Hudson commenced his observations by remarking upon the difficulties which beset any one at the outset who attempted to give a true definition of what a Rotifer was. This class of creatures had been variously described in different text books, but there had been no definition yet produced which would not be at once torn to pieces by the critic who attempted to make it apply to the whole group ; for though it was easy to describe typical forms, the further one got from the central figure the more the definition had to be shorn of its positive assertions, until so many of the leading features were at length dropped that the only part of the original definition remaining might be that of " small creatures which laid eggs ;" a distinction which, however, equally applied to hens and snakes. Instead, therefore, of attempting any universally appli- cable description, he proposed to show them a diagram of a typical Rotifer, and to explain briefly its distinctive structure. The room was then darkened, and Dr. Hudson proceeded to show as trans- parencies a series of admirably executed coloured diagrams as follows : — (1) Brachionus pala, as a typical form of Rotifer, showing cilia, water vascular system, alimentary system, repro- ductive organs, &c. In connection with this, it was pointed out that the whole family might be grouped into — (a) Those that swim and creep ; (&) those that swim only ; (c) those that are rooted for life to one spot ; (d) those that both skip and swim. This plan C. T. HUDSON ON THE ROTIFERS. 165 of division followed the classification of Dujardin, who, though an admirable critic, had done very little original work. (2) Rotifer citrinus — having the property of reviving again after being dried ; the process of covering themselves with a gelatinous coating to resist drought, as explained by Mr. Hy. Davis — was referred to. (3) Actinurus Neptunius — one of the rarer Philodines. (4) Hydatina senta. (5) Some curious parasites found in the stomach of Hydatina. (6) Notommata aurita — its method of capturing and devouring Vorticellse described. (7) Trochosph&ra cequatorialis — rare foreign form. (8) Pterodina valvata. (9) Euchlanis triquetra. (10) Lacinularia socialis. Dr. Hudson remarked that it had been formerly held by Professor Huxley that Rotifers were the permanent forms of Echinoderm Larvse. He need not trouble the meeting by following out the subject further than to say that the Professor's argument partly depended on the assumption that the Rotifers could be divided into a monoecious and a dioecious group, and that Lacinularia socialis had been placed in the former. It was probable that Professor Huxley had since seen reason for modifying this conclusion, because male Rotifers had now been discovered in all the great groups, with one exception ; and he himself (Dr. H.) had had the good fortune to discover, among several others, that of Lacinularia. As the Quekett Club was a working society, these missing males might be looked for by the members. They were those of the Philodines — common Rotifers that might be found in every gutter — and yet no one had yet seen and recognised their males. Suppose the Q.M.C. should take it in hand! (11) The male of Lacinularia socialis. (12) A splancJma (male and female). (13) (Ecistes. (14) A group of CEcistes longicornis. (15) Limnias — specimen procured at Nausea. (16) Limnias — peculiar form. (17) Limnias annulatus — rare species. (18) Cephalosiphon — peculiarity mentioned of having its one large antenna on the wrong side of the body. (19) Diagram of a plant — Ranunculus aquatilis — to show the application of the method of illustration to botanical subjects. (20) Portion of plant, with red water mites ; also to show application of this method of illustration. (21) Group — with Melicerta. (22) Melicerta ringens, in various positions ; also small one commencing to make tube. (23) Meli- certa tubicolaria — placed in a distinct genus by Ehrenberg. (24) Floscularia campanulata — a most beautiful object upon a dark ground. Its method of capturing its prey was described, an 166 C. T. HUDSON ON THE ROTIFERS. instance given of an apparent exercise of reasoning faculty in the case of an individual which had caught an object too large to be drawn into its mouth and too rigid to be safely grasped by the disc. (25) Stephenoceros — very rare in the neighbourhood of Bristol. (26) Bowerbankia. (27) Annelid Larva3. (28) Pedalion, with its male. (29) Diagram of some of the ordinary things found at the sea-side, to show the applicability of the process of illustration to this class of subjects. In the course of his remarks, Dr. Hudson pointed out the great value of dark ground illumination in the examination of Rotifers, and gave some hints as to the means of successfully accomplishing it ; the essential conditions being perfect collimation, accurate focussing, perfectly clean glass slide, cover, &c, not too much water, and the absence of any extraneous matter either above or below the object. With regard to the preparation of his diagrams, he described them as being made of stout " endless ' : brown paper ; the outline of the picture was drawn upon this, and then cut out, and the space filled in again by pasting a piece of tracing cloth over it. The colouring was for the most part done by sticking on pieces of coloured tissue paper, the shading being effected either by additional thicknesses of tissue paper or by a brush ; paints might also be used at discretion to produce effects as required. The cilia were represented by small holes punched out of the cloth or paper with a fine punch about the size of an ordinary pin's head ; and the high lights were produced by cutting through the cloth and covering with tissue paper only. 167 On the "Micro-megascope." By John Matthews, M.D., F.R.M.S. (Communicated February 28th, 1879.J Mr. President and Gentlemen, — I must confess to a consider- able amount of reluctance to occupy the time of the meeting at this late hour, and after the very admirable and lucid lecture to which we have been listening. I will try, therefore, to explain as briefly as possible, the nature of the apparatus now before you, and perhaps the best way of introducing the subject may be to give you some idea of the course of reasoning which has led me to its construction. Within the last year or two I have been studying the mode of for- mation of, as well as the conditions which contribute to, the optical images produced by lenses, and one amongst other experiments I have tried is, whether the spherical dots (areolations ?) on the frus- tules of certain diatoms, would give images of objects suitably placed before them, in the same manner as the lenses in the cornea of an insect. I found that they did so. I then tried various corneas and diatoms, and as each afforded images varying in size only, and perhaps in definition, when examined by the same power, it next occurred to me that if I were to use a single and more perfect lens, a larger as well as more distinct image would be obtained. I there- fore placed an ordinary objective — by means of a suitable adapter — and having its front combination upwards, either in the substage or on the ordinary stage, as might be most convenient.* I then found that I got a very perfect image of any object to which it was directed, when it was examined by the objective in the usual place on the * Since the above communication was made, I have been informed, and have satisfactorily ascertained, that Drs. Curtis and Ward, of the United States of America, devised a very similar arrangement, and published it in the "American Naturalist" for Nov. and Dec, 1870, and Sept., 1871. Extracts from their papers will be found in the " Monthly Microscopical Journal " for 1871 and 1872. The method of application was in both cases somewhat ambiguous. — J.M. 168 J. MATTHEWS ON THE MICRO-MEGASCOPE. body of the microscope. It was also erected and varied in size and definition with the power used, as also with the distance of the object. But I soon observed not only that it was difficult to illuminate a translucent object placed below the stage, but that the distance to which that object could be removed, was practically limited by the height of the microscope above the table ; unless, indeed, the in- strument were placed horizontally, which was not a convenient position in practice. To remedy this, I thought of adjusting a translucent object or slide to the flat side of an ordinary condenser, in the usual place between the lamp and the microscope, so that its image might be reflected by the plane mirror upwards through the substage objective. This plan effected exactly what was required by diverting the line of sight in such a manner that it was possible to place the object at any distance, and its image being thus varied in size, might (or could) be exactly included in the usual field of the microscope, and when there, easily examined by objectives and eye- pieces of almost any power. By this simple plan the powers and uses of the instrument were immediately increased, practically without limit, as I will now proceed to show. The objectives of the lowest powers which have hitherto been used are the 5 and the 4 inch. Now, with the ordinary A eye-pieces, the diameters of their field of view are ( about) '5 and '4 of an inch only, and so on with th e other lowpowers — the field, of course, lessening in degree. But there are many objects, such as large sections of woods, insects, corals, and various other things, which it is often most desirable to see wholly, and then to examine in detail. This is obviously impossible by any means hitherto used, except the lantern and the erector. Of the former I need not speak. The uses of the latter are so limited, that it has met with very little favour of late years, although it is very useful where the object " requires any kind of manipulation," or " where an extensive and yet limited range of magnifying power is required without any change in the objective." — (Carpenter.) By this new arrangement, the object suitably illuminated is placed just so far from the mirror as to fill, when examined by the usual objective, preferably a two-inch and A or No. 1 eye-piece, the whole of the field exactly. There is no doubt that, in principle, the micro- scope is thus converted into a telescope of any power that may be required. The ordinary achromatic condenser has always been focussed by examining the image of the flame of the lamp, or that of the bars J. MATTHEWS ON THE MICRO-MEGASCOPE. 169 of the window of the room when used bj daylight. Here, then, was the germ of the invention lying unnoticed for want of develop- ment. I believe that some time ago Mr. James Smith showed this method of using an objective on the substage, but, as I am informed, no more was done with the apparatus than to show opaque objects well illuminated, and its uses were thus much restricted, no mirror or prism having been used. Lastly, on examining my plan of using the plane mirror critically, I found that, in every case, there was a slight confusion of the two images given by its first and second surfaces. In a large proportion of cases this is of no consequence, but in some it certainly does more or less impair the definition. I have, therefore, caused a right- angled prism to be fitted up in its place, the reflections from which leave nothing to be desired, either in definition or light. It will readily be seen how valuable this plan may become in drawing, the size and scale being wholly at command, and if the instrument be placed horizontally, neither mirror nor prism are required. I have called the instrument a Micro- megascope, because we have with it the power of either magnifying or diminishing an object at will. 170 On the Dual-Lichen Hypothesis. By M. C. Cooke, M.A., LL.D., &c. CRead March 28th, 1879. ) [Abstract.]* " That hypothesis which is based on sound scientific knowledge is sure to have a corresponding value, and that which is a mere hasty random guess is likely to have but little value."— Prof. Huxley Lectures (1863 j, p. 67. Truth has often been discovered by the aid of a hypothesis, hence the proposition of a hypothesis for the advancement of science is perfectly legitimate. Some hypotheses which have been proposed in the past have proved utterly untenable when they have been assailed ; therefore, before any hypothesis is accepted, it should be subjected to all possible tests. Any hypothesis which cannot suffer criticism is not worthy of acceptation. The dual-lichen hypothesis is worth very little if unable to meet all the objections which such an assailant as the present can urge against it. Without contenting myself with reviewing the remarks of single individuals, I will rather go direct to the main source of the theory of which Schwendener is the author. In a few brief sentences the whole gist of the hypothesis may be summarized. Although at first only the group called the Collemacece were included, ultimately, as his views extended, he included all Lichens in the category of Algo- fungi. These are his words, " As the result of my researches, all these growths (Lichens) are not simple plants, not individuals in the ordinary sense of the word ; they are rather colonies, which con- sist of hundreds and thousands of individuals, of which, however, one alone plays the master, while the rest in perpetual captivity prepare the nutriment for themselves and their master. This master is a fungus of the class Ascomycetes, a parasite which is accustomed to live upon other's work. Its slaves are green alga3, which it has * The full text of this paper will be found in " Grevillea " for March and June, 1879.— Ed. " Q.M.J." M. C. COOKE ON THE DUAL-LICHEN HYPOTHESIS. 171 sought out, or indeed caught hold of, and compelled into its service. It surrounds them, as a spider its prey, with a fibrous net of narrow meshes, which is gradually converted into an impenetrable covering ; but whilst the spider sucks its prey and leaves it dead, the fungus incites the algae found in its net to more rapid activity — nay, to more vigorous increase.""* In the volume " Fungi " in the International Scientific series, from page 10 to page 16, the theory in question is thus ex- plained : — " The two great points sought to be established are these, that what we call Lichens are compound organisms, not simple, inde- pendent vegetable entities ; and that this compound organism consists of unicellular algae, with a fungus parasitic upon them. The coloured gonidia which are found in the substance or thallus of lichens, are the supposed Algae, and the cellular structure which surrounds, encloses, and imprisons the gonidia, is the parasitic fungus, which is parasitic on something infinitely smaller than itself, and which is entirely and absolutely isolated from all external in- fluences, "f In plain words, the gonidia are algae, and all the rest of the plant is Fungus. At first sight it would appear that the whole con- troversy centered itself upon the definition of two words. A certain plant, with a peculiar organisation, has been hitherto by general consent represented by the term Lichen, whereas some modern writers contend that it should be called a Fungus, differing only from other Fungi in its power of enclosing certain unicellular algae within its substance. Shall these organisms still retain the name of Lichens, or shall they be called modified Fungi ? This is really one aspect which the hypothesis assumes, that of the value of two words. The theorists, on their part, maintain that it is something more than a mere definition of terms which is required, but they claim to have it accepted that Lichens (as they are called) are iden- tical with Fungi (as commonly understood) , but with the addition of certain extraneous bodies called "gonidia," which are truly micros- copic Algae. Some general objections to the hypothesis will afford evidence that there is still a broad space between the theorists and some of their opponents. * Schwendener, " Die Algentypen der Flechtengonidien," p. 3, 1869. t " Fungi, their nature, use," &c., pp. 11-12, 1875. 172 M. C. COOKE ON THE DUAL-LICHEN HYPOTHESIS. Are Lichens Autonomous Plants ? Is it, or is it not, possible from the structure or the development of a plant to predicate with tolerable certainty whether that plant is within itself a perfect or complete plant or not ? If we sow a seed under favourable con- ditions, preserving it from all external influences, and that seed germinates, produces a root, a stem, ultimately leaves, the flowers, with stamens and pistil, then in course of time, as the ovary matures, seed in all respects identical with that from which the plant originally developed ; in such a case we should certainly conclude that the plant under examination is a complete and perfect plant, possessed of all the essentials for the reproduction of its species. If, instead of following the plant through all its stages, we bring experience to our aid in judging of probabilities, we examine a plant possessed of root, stem, leaves, and complete reproductive organs, bearing perfect seeds, we may safely conclude that we are examin- ing a complete and perfect plant. All these organs we know by experience are not essential to the perfection of fruit in all plants. In some the stem will be almost obsolete, as in the daisy, or without true leaves, but with leaves and stem fused into a foliaceous expan- sion, as in the duckweed ; and yet there will be no suspicion that the plant is incapable of reproducing its species, thus proving itself a perfect plant (using the term perfect, as in the sense of complete- ness). Hence we may conclude that if a plant is capable of repro- ducing its species, when excluded from all external influences, by means of its own proper organs, we may assume such an one to be a complete plant, whatever modifications in structure may be present, and whatever secondary organs may be absent. Such plants, how- ever minute or simple in structure, are entitled to rank as autono- mous plants. The spores of a species of Peziza germinate, producing root-like fibrils of great delicacy, and upon these arise small globose bodies which, as they grow, become perforated at the apex, ultimately expanding into a cup, which completes the vegetation of the little plant. It is simply a minute fleshy cup, with a fibrous base, by means of which it is attached to the matrix. A section of this cup exhibits the reproductive bodies, the ova (if such a term may be permitted) contained in elongated tubes, closed at the apex, and packed side by side. These spores, when matured, are capable of reproducing the form and character of the parent. Yet simple as M. C. COOKE ON THE DUAL-LICHEN HYPOTHESIS. 173 such a plant may be, no one lias raised a doubt as to its being a complete plant. Another simple plant, with similar cup-shaped organs, or recep- tacles, enclosing similar reproductive bodies, contained also in cylindrical tubes, but with other organs superadded, such as a foliaceous expansion, analogous to leaf and stem, or it may be some other bodies characteristic of the group to which it belongs ; and at once analogy leads us to the conclusion that this also represents a complete plant. If we concede that the Duckweed is a perfect plant, and the Peziza also a perfect plant, then also the Lichen must be a perfect plant. Are Lichens (exclusive of their Gonidia] identical ivith Fungi ? The hypothesis in question assumes that the lichen consists of a fungus, enclosing certain foreign bodies, called gonidia. Hence then, lichens, irrespective of the gonidia, should correspond in all respects to the Fungi to which they are referred. The presence of these small organisms may be ignored in our comparison of the supposed fungus with the real fungus of our experience. In comparing the general character of Lichens with the general character of Fungi, we may assume that we can arrive at some definite conclusion as to the probability of their identity. We can predicate nothing of fungi except what is confirmed by fact ; and any other organisms, to be affiliated to them, must agree in all main features with the known characters of the Fungi, or they can have no claim to be considered identical. It will facilitate this comparison if we are enabled to limit the area, which may be done by accepting the limitation fixed by the Schwendenerian hypothesis that the Ascomycetous Fungi are meant when the term Fungi is used, and as the Sphceriacei have been vir- tually excluded by all advocates of the theory, it may be assumed, as has been admitted, that the Discomycetes are the special group of Fungi to which the Lichens are referred. The Discomycetes, in their cup -like forms, are assumed to be identical with the apothecia of certain lichens ; nay, more than this, all Lichens, to whatever genus they may belong, in their totality, excepting only their gonidia, are affirmed to be Discomycetous Fungi. " Lichens are perennial ; they grow very slowly, but they attain an extreme age. Some species, growing on the primitive rocks of the highest mountain ranges in the world, are estimated to have attained 174 M. C. COOKE ON THE DUAL-LICHEN HYPOTHESIS. an age of at least a thousand years ; and one author mentions, after the lapse of nearly half a century, having observed the same sjDeci- men of Sticto pulmonaria on the same spot of the same tree.* On the other hand, the Discomycetous Fungi are annual, very short-lived, their whole existence being limited to a few weeks, rapid in growth, and rapid in decay, not a trace of some species remaining after a few days. Lichens will exist under conditions of aridity which no other vegetables could support. Some are peculiar to calcareous rocks, a few are found on arenaceous rocks, many are common on the granitoid series, including micaceous, gneissic, granitic, and quartz- ose rocks, and Lee idea geographica is frequent on the purest and smoothest quartz. Fungi, on the contrary, must have moisture for their very exist- ence sake ; are mostly found in damp and shaded situations, and could never exist under the conditions just enumerated for Lichens. The highest mountains, beyond the snow-line, at 16,000 feet on Chimborazo, the extreme limits of vegetation at the North and South Pole are occupied by Lichens. Dr. Hooker found three species of Discomycetes in the Falkland Islands, to 116 Lichens. The Reindeer Moss and species of Umbilicaria flourish amongst the snow. On the other hand, frost and snow are fatal to Discomycetous Fungi, which disappear long before the snow- line is reached on mountains, and even before phanerogamic vege- tation in the direction of the Polar regions. Of all plants, Lichens support extreme cold most successfully, whilst Fungi succumb at the approach of frost. Lichens which grow upon the bark of trees may be seen flourish- ing in profusion during the life and vigour of the tree. It has been affirmed that the portions of Cinchona Bark which have been covered with Lichens during growth abound in the Alkaloids, on which their medicinal use depends, j whereas the portions attacked by * Dr. Lauder Lindsay, " Lichens," p. 52. f Pharmacologists are aware that the most valuable lands of Cinchona Bark, as, for instance, the " Crown Bark," are habitually covered with Lichens, and that this covering favours the development of the Alkaloids. Regarding this fact, the late Mr. Mclvor, of Ootacamund, introduced the plan of covering the growing branches of Cinchona plants with moss, and the bark thus mossed produced a larger percentage of Alkaloids than the naked bark. The operation may be purely mechanical, such as obstructing the light. However this may be, certainly no injury is inflicted, but benefit is conferred by the growing lichens. M. C. COOKE ON THE DUAL-LICHEN HYPOTHESIS. 175 Fungi are valueless from the tissue being destroyed by the ramify- ing mycelium. Indeed, Fungi do not and cannot flourish on growing and vigorous bark, but on diseased, dead, or decaying spots. Lichens obtain the greater portion of their pabulum from the atmosphere, and only their mineral constituents from the matrix. Hence they cover the trunks and branches of forest trees, without apparent injury, aud many species habitally nourish on the hardest granite. Fungi, on the other hand, obtain their chief support from the decaying vegetable matter on which they flourish, gathering up a large store of the nitrogenous results of putrefaction and decay, and disintegrating the matrix on which they prey. Lichens, in their chemical composition, contain a large number of substances which are wholly unknown amongst Fungi. Colorific principles, such as obtain in the Orchella weeds, Orcellic, Cetraric, Lecanoric, Tannic, and Gallic Acids, Lichenin, and even a peculiar and characteristic odour, all of which cannot be attributed to the gonidia they contain. Lichens contain but a small percentage of water as compared with Fungi, so that in dessication they do not shrivel, collapse, or perceptibly diminish in size, whereas Fungi shrivel up and collapse so as scarcely to be recognised, becoming liable constantly to the attack of insects, or, if damp, subject to the development of mould, whilst Lichens may be preserved for years under like conditions without fear of insect or mould. Lichens, when collected and cast aside without the slightest care or precaution, do not exhibit the least tendency to putrefy, whilst Fungi, with the utmost care in drying, can scarce be preserved from unmistakable evidences of incipient putrefaction. Any one who has examined the thallus of such a Lichen as Peltigera canma, and compared it with any known species of the Discomycetes, must come to the conclusion that amongst them there is no such structure to be found as that which prevails in the Lichen thallus, altogether irrespective of gonidia. It is sometimes useful and instructive on doubtful points to con- sult the instincts of the lower animals, and this course may be adopted with advantage in the present instance. Amongst Coleop- tera there is an entire family called the Mycetophagidce, many of which live upon Fungi, and yet do not attack Lichens. There are also some of the Bostrichidce and some species of Anobium very fond of Fungi, but they do not attack Lichens. The insects which o 176 M. C. COOKE ON THE DUAL-LICHEN HYPOTHESIS. destroy Lichens are few in number, and quite different in their rela- tionships from those which prey on Fungi. There is also amongst the Diptera a family called Mycetophilida, with like propensities, as evidenced by the genera Mycetophila, Boletina, Mycetobios, Bolitophila, and yet there are none so equally destructive or parasitic on Lichens. These insects must have come to a sounder conclusion than some men, that Lichens are not Fungi, with the addition of an innocuous green Alga. Surely if they had the same grateful food to offer, these insects would patronise the Lichens ; but as they attack all kinds of Fungi, and do not attack Lichens, insects certainly have not yet become converts to the Schwendenerian hypothesis. In concluding these comparisons, the only inference which ap- pears feasible is, that all these differences are so many reasons against the identity of Fungi with Lichens. There must be a most essential difference between them, beyond the gonidia, for the gonidia are not sufficient causes to produce all these divergencies. It is quite erroneous to state, as some have done, that the gonidia constitute the only difference between Lichens and Fungi, whereas the presence of gonidia is only one out of the many differences which exist between them. Are Gonidia a part of the Lichen-structure ? — The thalli of Lichens enclose within them peculiar cellules, forming a sub-cortical layer, which are sub-globose, of a greenish colour, and to these the name of gonidia has been given. They frequently burst through, and appear on the surface, in the form of powdery masses. The lichenologist believes, and as he thinks has good reason for believ- ing, that they form part of the plant itself. One says, " They may be regarded as intermediate in function between the vegetative and reproductive cell, assuming the offices and partaking of the char- acters of both."* The justly celebrated Tulasne considered them to be parts of the Lichen, and also to perform important functions. On the other hand, the theorists contend that they are no part of the plant, but that they are a form of Algge, upon which the residue of the Lichen is parasitic. The grounds of the belief are suppositi- tious, and the proof is still defective. In the first place, it is argued that they are free cells, resembling in size, form, and colour certain low forms of unicellular AlgaB, and * Lindsay, "Loc. Cit.," p. 41. M. C. COOKE ON THE DUAL-LICHEN HYPOTHESIS. 177 hence, as they are out of place in Lichens, they must be unicellular Algae. Any one who has had any experience amongst the low forms of vegetable life, in which the organism consists of a single cell, are exceedingly well aware that it is almost an impossibility, from the observation of these cells, to arrive at any satisfactory conclusion as to what they are, and what their ultimate development may be. Let them compare, if they please, what are known to be the earliest stages of Mosses and Algae with the gonidia of Lichens, and draw up characteristic diagnoses, if they can. All are globose cells con- taining a greenish protoplasm, and about equal in size. By what occult power can the theorists distinguish that which, it is admitted, they cannot describe ? Yet the best and most experienced Algalo- gists affirm that of all these forms the gonidia of Lichens are the most distinct and permanent in their character. The only safe method by which these low forms can be deter- mined, is by watching their development. In their simple condition of cells they are no more than mere buds, the ultimate form of which only the rash or foolish would predicate. If the gonidia of Lichens are true Algae, it is insufficient to state that they so closely resemble Algae that they might be mistaken for such ; there must be some undoubted evidence produced that they are Algae in fact, and not in appearance. Nylander, on the contrary, holds that they are organs belonging to the Lichen. He says, " I have adduced that the gonidia and gonimia of Lichens constitute a normal organic system necessary, and of the greatest physiological importance, so that around them we behold the growing (or vegetative) life chiefly promoted and active." Again he says, " The absurdity of such an hypothesis is evident from the very consideration that it cannot be the case that an organ (gonidia) should at the same time be a parasite on the body of which it exercises vital functions."* Now, it must be admitted that Dr. Nylanderis the facile princeps of Lichenologists. If it can be shown that these green cells perform an active part in the life of the lichen — in fact, that they are organs possessed of certain functions, then they cannot at the same time be foreign to the plant in which they occur. Nylander has shown that, whenever they are few in number, a proportionate decrease of vitality * Nylander, in " Grevillea," ii., p. 146, 147. 178 M. C. COOKE ON THE DUAL-LICHEN HYPOTHESIS. takes place. That the most vigorous functions of life are carried on in their proximity. As the Schwendenerian theory is wholly based on the belief that there is no genetic relationship between the hypha3 and the gonidia of the Lichen thallus, any proof that such a genetic relationship does exist is fatal to it. Dr. Minks, of Stettin, has directed his attention specially to the investigation of this point with very important results. He discovers in the hyphaa of Lichens two new organs, which he has designated geonangium and gonocystiam, which produce gonidia within the walls of the hyphaa themselves. These gonidia, because of their minuteness, he names micro-gonidia. He has seen these micro-gonidia in all the cells of the hyphas, whether in the vegetative or the reproductive parts. He sees them in the cortical layer, the medullary layer, the paraphyses, the young asci, the sporidia, &c. Thus he has established their existence, not only within the hyphae-cells of all parts of the Lichen, but also in all stages of its life-history.* These facts, so utterly subversive of the Schwendener theory, have likewise been observed and confirmed by Dr. Miiller, of Geneva, who says, " My results have surpassed my highest expectations. Not only have I proved the existence of micro-gonidia in all the organs mentioned above, after having treated them with caustic potash, sul- phuric acid, and tincture of iodine, but I have also seen them with my excellent immersion objectives, without any chemical prepara- tion ; and in favourable cases, I have even seen them with the non- immersion lower powers of Hartnack." He proceeds to say that these micro-gonidia are paler than the ordinary gonidia, and dis- posed in moniliform series in the axes of the hyphas, having a diameter of '001 mm. In certain tropical species, which had been exposed to a more vivid light than those in more northern lati- tudes, these micro-gonidia attained a brighter green ; for example, in Parmelia prolixa, var. erythrocardia, Miill., sent by Dr. Schweinfurth from Lake Nyanza, in Africa. In this Lichen they were so green that little difference of colour existed between them and the gonidia. j" If the " parasite " can produce within itself all which it requires * Since the above was written some Lichenologists have rejected the con- clusions deduced from Dr. Minks' experiments. Whilst contending that gonidia are organs pertaining to the Lichen, they consider them independent of the so-called Micro-gonidia. f Consult Minks on Micro-gonidia, in the " Eegensburg Flora," for 1878. M. C. COOKE ON THE DUAL-LICHEN HYPOTHESIS. 179 for its existence, then Nature has made a mistake in making it dependent on another being for its existence. Here, then, we have clear demonstration that the gonidia are developed within the substance of the Lichen itself in a determinate and uniform manner ; that, instead of being altogether foreign from the Lichen, they are generated within it, and hence (according to the hypothesis J the parasite produces from its own substance the host upon which it is parasitic. The admirable Memoir of Tulasne should be consulted in conjunc- tion with Dr. Minks' contributions to the " Flora," and it will be seen that the latter confirms and amplifies the former, adding thereto new facts, and thus, doubtless, establishes the true relationship of gonidia to the residue of the Lichen. Is Parasitism proven ? — A parasite is usually defined as an animal or plant which lives upon or attaches itself to another, and derives therefrom sustenance and support. The misletoe, which attaches itself to poplar and other trees, is a parasite. The mould which attacks and destroys potatoes, is a parasite, entozoa are parasites, and so also are the pediculi, and other insects which infest the higher animals. In ordinary conversation there is seldom likely to be any misconception of what is a parasite. In all known instances of parasitism, it is, I presume, admitted that the parasite thrives and flourishes at the expense of its host. In every known instance of parasitic fungi the fungus lives at the expense of its host, which it injures and ultimately destroys. Schwendener himself says, " the vine and potato fungus, as well as all other fungi which vegetate in living organisms, destroy their host plant, or host animal, in the un- equal struggle." This universality of destructive parasitism in fungi knows no exception, and is, therefore, equivalent to a natural law. Any hypothesis which depends upon fungal parasitism, must of necessity recognize this fact, and conform to it. The fact cannot be reversed to save the hypothesis. Our experience of fire, in whatever form it occurs, is that it burns or consumes that upon which it operates. We have no ex- perience of fire which does not support itself by causing that change of form and condition which we term combustion. Hence we are justified by experience in rejecting any theory based upon a reversion of this fact, that is, on the assumption that fire does not consume. Inasmuch as the supposed fungus, said to be parasitic upon the 180 M. C. COOKE ON THE DUAL-LICHEN HYPOTHESIS. gonidia, does not " destroy its host plant, in the unequal struggle," it cannot be a fungus, since, if it were a fungus, the gonidia would be destroyed, as demonstrated by experience. Or, if it were proven to be a fungus, then, not being parasitic, the gonidia are not foreign to it, but a portion of its substance ; and again a dilemma occurs, for no fungus is known persistently to enclose green granules. Relative size is another strong presumption against parasitism. In the Lichen we have a supposed parasite many times larger than its host. It is an elephant parasitic upon a flea, and not a flea upon an elephant. The parasite in the romance encloses and cherishes its host, which is buried within its substance, reminding one strongly of an entozoon, enclosed in the body of an animal, horse, dog, or man. In such a case it is not usual to call the man or the animal the parasite, and the entozoon the host, but the reverse. If it is urged that this is not an analogy, because the entozoon is known to subsist upon the animal in which it is found, then, in like manner I would urge that it is not proved that the gonidia do not subsist at the expense of the so-called fungus. In other words, it is more feasible to suppose that the assumed green algae are parasitic than that they should be the host. Again, if it can be shown that gonidia are part of the whole plant, they cannot be distinct from the plant. If they are produced by the healthy and normal action of the plant, then they are attributes of the plant. If they are beneficial to the plant, acting as organs, per- forming useful functions, then there is no more parasitism than in the leaves of an oak or the tendrils of a vine. It is needless to recapitulate what has already been alleged that the gonidia are generated by the plant itself, and hence there can be no parasitism. Dr. Nylander writes : " The absurdity of such an hypothesis is evident from the very consideration that it cannot be the case that an organ (gonidia) should at the same time be a parasite on the body of which it exercises vital functions ; for with equal propriety it might be contended that the liver or spleen constitutes parasites of the mammiferas. Parasitic existence is autonomous, living upon a foreign body, of which nature prohibits it from being at the same time an organ."* All conclusions as to the general character of Lichens, based upon * "Grevillea" ii, p. 146. M. C. COOKE ON THE DUAL-LICHEN HYPOTHESIS. 181 experiences of the Collemaceae, are essentially unsatisfactory. It is widely admitted, and has been for many years, that the Collemaceaa are aberrant forms of Lichens, even if they be Lichens at all. The genera Collema, Leptogium, Synalissis, Myxopuntia, Oniphalidium, Paulia, Lichina, and Myriangium have been named together, as forming a group with the thallus of an Alga and the fruit of a Lichen. Some have excluded them from Lichens altogether, others have accepted them with reserve, as aberrant forms, and all this was done before any Schwendener hypothesis was dreamt of. Montagne and the Rev. M. J. Berkeley at one time were disposed to include all these genera under the name of Collemacece, as distinct from Lichens proper. (See " Lindl. Veg. King.," p. 49.) Cohn afterwards excluded them in a proposed arrangement. Hence we may conclude, that whether they are included with Lichens or not, they are aberrant forms, in no sense typical of Lichens, and cannot be held as evidence in any dispute as to the character of Lichens as a whole. Weighed and found Wanting. — It only remains to sum up the evidence and apply it to the purpose for which the foregoing re- marks were designed. It is perfectly legitimate to construct an hypothesis with the view of ascertaining the truth, but it appears to me that such an hypothesis should be tested in three ways- It should be considered as demonstrated, on the one hand, or be rejected altogether, on the other, if it stands or falls by these three tests : I. — We should be prepared to ascertain whether our hypothesis is consistent with existing scientific facts. II. — Whether the hypothesis is sufficient to account for the phenomena in question. III. — Whether the phenomena can be produced in any other manner. I. — As to the harmony of the hypothesis with existing scientific facts. The assumption that two separate and distinct organisms are combined in one plant, which, by its own proper system of re- production, is capable of continuing its species, each individual of its progeny also exhibiting the same phenomena of assumed dual existence, is inconsistent with known scientific facts, because, whilst one supposed plant proceeds from its proper germ, the other has none, and is, therefore, spontaneously evolved. Thus, if the Lichen, by means of sporidia, is capable of pro- 182 M. C. COOKE ON THE DUAL-LICHEN HYPOTHESIS. ducing plants which are, in all respects, like the parent, then the sporidium of the fungus element reproduces also the algal element, and the same spore, or ovum, is the origin of two distinct and widely diverse organisms, i.e., a fungus and an Alga, which is inconsistent with scientific fact. The seed of the maple reproduces the Maple tree only, its parasite, the Rhytisma, establishes its parasitism afterwards by means of its own proper spores. Thus it is with other hosts and other parasites. If one germ is the origin of both the dual elements in a lichen, then these elements must both be considered as parts of a single individual. The theory assumes, further, that a fungus is parasitic upon a smaller and weaker organism, which it does not injure or destroy. This, again, is contrary to scientific fact, as it confers upon, or assumes for, a destructive force, conservative powers. The hypothesis assumes also that all the substance of all lichens, except the gonidia, are fungi, whereas, as has been shown, their structure, composition, habits, &c, &c, all differ materially from fungi, to such a degree, that they cannot be regarded as identical. The hypothesis assumes also that the gonidia are certain forms of other plants, which they externally somewhat resemble, whereas the gonidia are organs of the lichen, performing definite functions in its behalf. Hence, briefly, there remains no other conclusion but that the hypothesis fails to support the first test, because it is not consis- tent with existing scientific facts. II. — Whether the hypothesis is sufficient to account for the phenomena in question. That is, whether the combination of a fungus and alga is sufficient to account for the production of a lichen, or to state the hypothesis in the phraseology of its advo- cates, whether a fungus parasitic on an alga is a sufficient cause to account for a Lichen. Unless it can be shown that the fact of its parasitism is sufficient to alter the entire character of a fungus, it is not a sufficient cause to account for the existence of Lichens. Unless it can be admitted that parasitism will convert a fugitive, short-lived fungus into a perennial lichen, induce it to live on a dry, barren rock, which, as a fungus, it could never accomplish, to support great extremes of heat and cold, to submit to frost and snow without destruction, to flourish on growing trees, whilst still vigorous, and without indue- M. C. COOKE ON THE DUAL-LICHEN HYPOTHESIS. 183 ing decay, to assume a fibrous structure instead of a cellular, to produce certain acids within its tissues, which are unknown to it in other conditions, to exchange a putrefactive tendency for a persistent one, to abandon for ever a career of pertinacious des- tructiveness for one of inoffensiveness, in short, to reverse its entire character, unless it can do all these things as a result of parasitism on the minute green cells of an Alga, then the fact of such a para- sitism is insufficient for the production of the phenomena. Inasmuch as we have no experience of such a total change in the essential characters of fungi under any conditions of climate, or local circumstances, we cannot admit that simple parasitism will cause such a change. Numerous instances of parasitism are found habitually to occur amongst fungi. Many species exist in no other form than as parasites, and yet no alteration in the direction of lichens is known to take place. Therefore we are compelled to adopt the conclusion that the hypothesis is insufficient to account lor the phenomena in question. III. — Whether the phenomena can be produced in any other manner. It is almost needless to say much under this head, having already shown, as we proceeded, that all the phenomena of lichen life are wholly compatible with the assumption that these organisms are, in themselves, true, simple, autonomous plants. If, also, we are right in the conclusion that the hypothesis fails when submitted to the two preceding tests, the natural inference will be from the arguments already adduced, that all the phenomena which any Lichen exhibits are compatible with a simple organism. The Theorists admit, by their hypothesis, that all the phenomena, except the gonidia, are wholly compatible with a plant which they call a Fungus. Although we do not admit that Fungus is the correct name to be given to the plant, we also affirm that it affords evidence of being a simple plant, but with the addition of the gonidia, which we hold to be as possible as conidia enclosed within the substance of a Fistulina or a Polyporus, and not only possibly, or even, probably, organs of the Lichen, but that positively such is the case. We require no counter hypothesis, therefore, to support our view, but urge, on the contrary, that where an organism is seen to exist, and continues to reproduce itself in conformity with a certain type, it is folly to attempt, by multiplying causes, to account for phenomena in an abnormal manner, which can be readily accounted for by normal causes. 184 M. C. COOKE ON THE DUAL-LICHEN HYPOTHESIS. When we see an organism in possession of certain organs, which organs perform certain functions, however small, and these organs and functions are inherited and transmitted, there is a pretty strong presumption that all our efforts to demonstrate external causes, to account for pliEenomena already well accounted for, we shall only embark on a profitless speculation. At present there are still a few who are content with this view of the Lichens, and do not crave the novelty of a dual hypothesis. As to the assertion that the hypothesis is now generally received and adopted, come from what quarter it may, it must be accepted for what it is worth ; even if endorsed by the " Nineteenth Century" it will certainly be forgotten in the twentieth. Such an hypothesis cannot practically be accepted whilst it is rejected by the Licheno- logists and Mycologists. It must resolve itself into a question of classification, and so long as the best classificatory books are written by the best men, Lichens will continue to be Lichens, and Fungi much the same as they are. 185 PROCEEDINGS. December 13th, 1878. — Conversational Meeting. The following objects were exhibited : — Head and Organs of Mouth of Drone Bee Mr. F. W. Andrew. Mr. W. Goodwin. Mr. J. J. Hunter. Dr. Matthews. Earwig — Polarised... Transverse section of Molar Tooth of Horse Petiole of Chestnut — showing the horse-shoe") arrangement of its air cells and crystals > Mr. A. Martinelli. of mineral matter, in situ ... J Two rare varieties of Madrepore Corals on Sponges, showing parasitism Hooklets of genital organ of Pontia brassica,' being in the female only of that species, 5> and absent in the male Mantle lobes of Terebratula caput-serpentis, showing the calcareous spicules Aristolochia ornithocephala... » sipho Sections of Broom... „ ,, Tillandsia glaucophilla ... Sections of Wistaria „ „ Rose ... Mr. J. Slade. Mr. F. H. Ward. Mr. T. C. White. Attendance— Members, 57 ; Visitors, 10. December 27th, 1878.— Ordinary Meeting. T. C. White, Esq., M.E.C.S., &c., Vice-President, in the Chair. The minutes of the preceding meeting were read and confirmed. The following gentlemen were balloted for, and elected members of the Club:— Mr. Andrew Chatto, Mr. H. A. Erlebach, Mr. Frank C Kellow, Mr. M. G. Martiney, Mr. John M. Reid, and Mr. C. W. Salmon. The following donations to the Club were announced : " Proceedings of the Royal Society " f rom the Society. "Transactions of the Royal Microscopical Society" " Proceedings of the East Kent Natural History l Society" j » " 186 " Science Gossip" from the Publisher. "American Naturalist ... ... ... ... in Exchange. " American Journal of Microscopy " ... ... „ „ " Annals of Natural History ... ... ... by Purchase. " Specimens of an Infusorial deposit from Cym~) from Dr. Solterforth Bychan Lake* ... ... ... ... ) per Mr. T. Curties. Photograph of Mr. F. Oxley, for the Club album. The Secretary said that he had been requested to announce the following Soirees, and to ask the assistance of those members of the Club who might be able to be present at either of them : — That of the Greenwich Micro- scopical Society would take place on Wednesday, January 8th, 1879 ; the New Cross Society would hold theirs on Tuesday, January 28th ; and the South London Society's would be held at the Crystal Palace, on February 19th. Mr. Charles Stewart made some highly interesting observations upon Lichens, which he freely illustrated by coloured drawings made upon the black board as he proceeded. After describing the important role in the economy of nature which was played by the tribe of Lichens, and point- ing out their peculiar powers of resisting drought, their usefulness as pioneers for other vegetation, and their commercial value as a source of dyes and an article of food, Mr. Stewart stated that in order to obtain some clear idea of their structure it would be necessary to acquire a knowledge of that of certain low forms of Algae and Fungi. Nostoc, an Alga found in the form of gelatinous material encrusting rocks, &c, was then figured and described, together with Cystococcus, a cellular form frequently found upon palings, &c. The general characteristics of the Ascomycetous Fungi were then explained at some length, and the minute structure of Peziza was figured and described, its reproduction and develop- ment being traced through their various stages. The apparently identical structure of the Lichens and Ascomycetous Fungi was next alluded to, and it was shown that the cellular formation of the lower Algae was present in addition, from which the inference was drawn that both Algae and Fungi had contributed to the production of Lichens. Some further drawings illustrative of this combined structure were then made, and the relation between them was pointed out with great clearness. The Chairman said that the subject before them was one which no doubt would at first sight strike any one as being decidedly dry ; but he was quite sure that, under the lucid treatment of Mr. Stewart, it must have become most interesting to all. As a class, these lichens were most beautifully dis- persed, and it only required a leading hand, like that of Mr. Stewart, to make any one take an interest in them. He hoped that many would be induced to take up the subject. Having invited remarks upon the subject, he called upon Dr. M. C. Cooke to say something upon it. Dr. M. C. Cooke said that he had, in the first place, to thank Mr. Stewart for the lucid, clear, and interesting manner in which he had laid before them a theory which had many supporters, and which had now extended itself * A list of these diatoms will be found in the " Proceedings of the Chester Society of Natural Science," No. 2, p. 28. 187 pretty widely. But although this theory was widely extended and widely entertained, it was by no means to be concluded that it was therefore true. He thought it was quite fitting that, at a time of year when romance was held to be in fashion, this, one of the prettiest little bits of scientific imagination, should be brought before them. Nevertheless, he regarded it as being from beginning to end, root and branch, totally and entirely false, and without a single good fact to stand upon. In connection with this theory, three classes of scientific men were brought upon the tapis — the Algologists, the Lichenologists, and the Fungologists — but though it was said to have received the support of many, he made bold to say that amongst them all there was not a single one of real eminence who had ever supported it, but that it had been carried out entirely by intermediate men, and remained only a theory, It was very true that there was between these things much of external similarity, but there was no analogy — there was much theory, but no fact. He had, during his time, had some little experience as to fungi ; there was hardly, in fact, a night on which he did not examine something like fifty of them, so that he might be said to know something about them ; but directly he put his knife into a Lichen he knew what he had got, even if his eyes were closed, such an entire difference was there in the substance ; and although there might be some sort of apparent resemblance, when they got them under the microscope it was evident directly what they were. He had also studied in his time the Pezizaa, and knew something about them, and could therefore say that, although they appeared to be very similar upon the black board, yet there was between the things themselves as much difference as there was between the moon and what they sometimes saw in the cheesemongers' shops. He did not propose to deliver any lecture upon the subject, but merely took this oppor- tunity of protesting, thinking it quite sufficient to say that he entirely dis- agreed with the theory, on his own part, and that he knew of no Fungologist of any note who did otherwise. Dr. Nylander did not accept it, and Leighton and Crombie both had shown that they saw no ground for it. It had, however, been put before the members of the Club by Mr. Stewart in a very admirable and interesting manner, and he congratulated him on having made the best that could be made of a very bad job. Mr. Crisp said that the subject of Lichens ought to be a very interesting one to Microscopists, inasmuch as the exact position of the Cryptogam in the vegetable kingdom still afforded scope for extended and careful investi- gation which, for the most part, could be carried out only by the aid of the microscope. It had always struck him as very remarkable that amongst Microscopists there should be so many Fungologists and so very few Lichenologists. Lichens had up to recent times been a little studied and little understood class, and the student, as had been seen, found himself met by contrary opinions of various writers, without much, if any, guide to enable him to form an opinion as to whether they were Algae or Fungi, or intermediate between the two, or what they were. With regard to Dr. Cooke's statement, it should be observed, that Sir Joseph Hooker, in his anniversary address as President of the Royal Society, on November 188 30, had pronounced in favour of the Schwenderian theory (passage read), which was strongly endorsed by Sachs, and confirmed by the results obtained by Bornet, Bees, and Stahl, who, proceeding synthe- tically, sowed Lichen spores on or near Algas, and obtained thereby true Lichen thallus, and not only that, but in the case of the latter observer, it was demonstrated that the same Alga in connection with different Ascomycetes produced different Lichens. It might be of in- terest to the meeting if he were to describe briefly some investigations which had recently been undertaken by Mr. Babikoff and presented to the St. Petersburg Academy. If certain Lichens were examined, there would be found upon them oblong or orbicular tubercles, consisting for the most part of masses of gonidia, which were known under the name of Ceplia- lodia. It had been suggested some years ago that these were an abnormal formation produced by algae which had accidentally fallen upon the surface of the Lichen, and it was to ascertain the correctness of this view that M. Babikoff made a study of the whole life-history of the Cephalodia. By cultivating the gonidia, he found that they consisted of Nostoc containing Phycochrome, those of the Lichen itself containing Chlorophyll, and he was able to follow the progress of development from the earliest period down to the mature state of the Cephalodia. Mr. Crisp then, by drawings in coloured chalks, made by Mr. Stewart on the black board, showed (1) the commencement of the development of the Algas by ramified hairs of the surface of the Lichen ; (2) the stage of complete development, the hypha of the Lichen forming a continuous tissue with the Cephalodia, and the gonidia interrupted beneath the latter; (3) the more advanced stage showing the disappearance of these gonidia, and the conversion of the tissue of the Lichen beneath the Cephalodia into very interlaced hypha, which degenerate lower down into Bhizines ; and (4) the final stage of separation of the Cephalodia from the Lichen. Mr. Charles Stewart said he had very few more remarks to make ; he could only repeat what he stated at first — that he had but slight practical acquaintance with the subject, though he certainly thought from reading that the balance of evidence was in favour of the theory that Lichens were cases of special Fungi parasitic on certain Algae. That there should be some difference, he was quite prepared to find, but he was not aware that there was after all any radical difference; and cer- tainly on comparing the Gonidia with known Alga3 he thought that there was a remarkable resemblance. He had been particularly struck in examining the Lichens in the neighbourhood of London, where the com- plete development of the tlialli (?) was arrested by the impurity of the atmosphere. Finding from examination of these Lichens that the Hyphae and associated algoid cells were exceedingly like the Hyphae of a Fungus and known Alga, he naturally came to the conclusion that the circum- stance was in favour of the dual nature of the Lichen. There were just two other points which he would like to mention — one was with regard to the mode of growth in Lichens ; sometimes the Alga element seemed to be in greater proportion than the Fungoid, and then the growth was 189 found to be very much like that of an Alga, but at other times the Fungus element prevailed, and the growing forms were accordingly more like the Fungi. The other point was that under ordinary circumstances the Gonidia were entangled, but had been seen sometimes to be fused with the Hyphae ; this was clearly explicable on the supposition of the latter being parasitic. (Diagram drawn showing the cell wall of the Hyphae being fused with that of the gonidium.) Illustrative specimens were also exhibited under the microscope. The Chairman thought the members would respond very heartily to a proposal that a vote of thanks be given to Mr. Stewart for his very interesting communication. Dr. Matthews said that he had always thought it to be their duty, as well as their privilege, to appropriate, but with due acknowledgment, the labours of their predecessors and contemporaries. Now, there were two ways of doing this — there was the way which might be called with more correctness mis-appropriation, namely, that of the poet, who was described by the satirist as stealing his verses from half the town — " But reading them damnably, made them his own ;" there was also the case of the man eulogised by the old Roman writer who — " Touched nothing that he did not adorn ;" and this remark, he thought, might well be applied to their friend, Mr. Stewart. He thought that they were much indebted to Mr. Stewart for the very able and interesting manner in which he had brought this subject before them — personally, he felt much indebted to him for so doing. As regarded the theory involved in that subject, he was not prepared nor indeed competent to express any opinion ; it might be only a theory after all, and yet it was supported by some very high authorities. Perhaps it was too soon to decide the question in one way or the other ; but however that might be. it was one well deserving their attention. He had great pleasure in seconding a vote of thanks to Mr. Stewart. The vote of thanks was then put to the meeting, and carried by accla- mation. The Chairman announced that, at the next gossip night, Mr. E. T. Newton would give an account of the General Structure of an Insect, and at the next ordinary meeting would read a paper upon " A Method of Making Models of the Brains of Insects from Microscopical Sections." The meeting then terminated with the usual conversazione, at which the following objects were exhibited : — Stem of Synapta inlieerens (polarised) ... Mr. F. W. Andrew. Leaf of Adiantum cuneatum, stained and polarised Mr. T. Curties. Minute Diptera ... ... ... ... Mr. H. E. Freeman. Protococcus, showing its cell-division ... ... Mr. A. Martinelli. Cuttle bone ... ... ... ... Mr. J. Slade. 190 Collema (apothecium and thallas) Pliystira, section of apothecium spore in asci and paraphyses Young Lichen, showing fungus, hyphaa, and gonidia Calicium, showing spores in asci Solorina, section of apothecium spore in asci and paraphyses Transverse section of French Honeysuckle Section of Tooth (polarised), showing layers } of new bone, the product of inflammation) y Mr. C. Stewart. Mr. F.H.Ward. Mr. T. C. White. Attendance — Members, 43 ; Visitors, 9. January 10th, 1879. — Conversational Meeting. The following objects were exhibited : — Melobacia on Seaweed Pollen of Myosotis disstiflora, curious for its minute size (1-4,000 X 1-8,000 inch), and Dumb-bell form ... Section of lower jaw of Mole Sertularia argentea... Thrips (Physopoda) Transverse section of Human Medulla Obion- 1 gata, measuring \\ inch in diameter ... Seeds of Carrot Damatus geniculatus — I. — Young larva in the act of escaping from the egg, showing the singular manner in which the long legs are packed in the egg II. — Larva — more adult — showing the mode in which it protects itself by a pile of dirt on the back Sponge Spicules, from Carboniferous Limestone"! of Ayrshire ... ... ... ) Dissection of Blatta orientalis (to illustrate his demonstration) Actinophrys sol — three in conjunction, and containing Daphnia Sponge Spicules, from root of a Coral Larva of Comatula rosacea, showing its mode of attachment to a seaweed Transverse section of stem of Misletoe and Apple Vertical „ „ „ Transverse „ Ovarium of White Lily } Mr F. W. Andrew. Mr. T. H. Buff ham. Mr. C. G. Dunning. Eev. H. J. Fase. Mr. H. E. Freeman. Mr. J. J. Hunter. Mr. A. Martinelli. y Mr. A. D. Michael. Mr. S. H. Needham. Mr. E. T. Newton. Mr G. D. Plomer. Mr. B. W. Priest. Mr. J. Slade. Mr. F. H. Ward. 191 Section of Clematis vitalba, double stained ... Mr. T. C. White. Mr. E. T. Newton gave a highly interesting description and demonstra- tion of the anatomy of an insect. Attendance. — Members, 65 ; Visitors, 10. January 24th, 1879. — Ordinary Meeting. Prof. T. H. Huxley, F.R.S., President, in the Chair. The minutes of the preceding meeting were read and confirmed. The following gentlemen were balloted for, and duly elected members of the Club— Mr. Arthur Avery, Mr. George T. Barham, Mr. R. C. C. Bond, Mr. Julian Deby, Mr. Chas. W. Easty, Mr. Burcham Harding, Mr. Arthur H. Lancaster, Mr. James Murray, Mr. John M. Offord, and Mr. S. K. Wilson. Eight gentlemen were proposed for membership. The following donations to the Club were announced : — " Proceedings of the Watford Natural History") „ , _ . Society" ... ... ... j- om e ocie y. " Proceedings of the Chester Society of Natural") - , , ~ . , Science 5 ' ... ... ... ) " The American Naturalist " ... ... in Exchange. " Proceedings of the Belgian Microscopical") frQm ^ Societ Society" ... ... ... ) " List of Publications of the Smithsonian Insti-") e ,, T ... ,. > trom the Institution. tute" ... ... ) " Science Gossip " ... ... ... ... „ the Publishers. " Annals of Natural History " ... ... Purchased. " Popular Science Review "... ... ... from the Publishers. " Grevillea " ... ... ... ... Purchased. * ' The Midland Naturalist "... ... ... „ A large number of drawings and engravings') of Sponges, with Pamphlets, &c, on the > Dr. M. C. Cooke. Subject ... ... ... j A Photograph of Prof. Quekett ... ... Mr. T. Curties. The thanks of the meeting were voted to the donors, and especially to Dr. M. C. Cooke for his valuable addition to the stock of drawings, &c, already presented by him to the Club. The Secretary reminded the members that the Soire'e of the South London Club would take place on Feb. 19th, and that he would be happy to receive the names of any persons willing to assist as exhibitors on that occasion. Mr. T. C. White read a paper by Mr. F. A. Bedwell — " On the Urticating threads of Actinia parasitica ." Mr. White said he had frequently seen and examined these threads him- self, and had generally found that they were projected from apertures of P 192 those Anemones which were rough ; such, for instance, as Crassicornis. He had sometimes seen them projected as long as 10 inches. In examining them he had done as Mr. Bedwell suggested, and cut off portions, and he quite agreed with him that the beads were rounded and ciliated, and crammed full of little dart-like needles. The plate in Mr Gosse's book would, no doubt, make this clearer than any explanation which he could give. Dr. Matthews said there was one curious circumstance about the threads, which he thought worth mentioning ; he had examined them under high powers, but not one vestige of muscular fibre could he find, and yet it seemed perfectly evident that they were actuated as much by muscular action as any other part of the organism. Another question of interest was, whether the poison, or means of offence, was of an animal nature, or whether it was electric — both had been suggested. The President said that, though he was not familiar with the particular organism which formed the subject of the paper, he was very well acquainted with the corresponding organs of the Hydrozoa, the whole of which class were provided with apparatus of this kind. The so-called " Portuguese Man-of-War " — the PhysaMa — had the most formidable battery of this kind of any animal in the world, the tentacles hanging down some 7 or 8 feet long, and being beset with reniform thickenings, each of which was stuffed full of thread-cells. He was not surprised that there had been difficulty in observing the presence of muscular fibre, because, though it was there, it was probably all of an unstriped kind, and therefore somewhat difficult to make out. The question of the cause of the irritation produced by these thread-cells was a curious one ; he thought, however, that they might put aside the idea of electric action, because the facts could be sufficiently accounted for without such a supposition. As regarded the Phy- saMa, if any one felt inclined to try it they would find that the stinging sen- sation produced was much more severe than that of the worst stinging nettle they ever experienced ; and if, whilst a person had his hand partially covered with these stinging organs, he happened to pass his hand over his face, the effect produced was of a most enlivening character. It was the outer layer of the tentacles which contained the stinging organs, each of which con- sisted of an elastic sac containing a long thread. When touched, the sac was turned inside out with surprising rapidity, and the small spine-like threads came in contact with the object which had excited the action — in the Physalia they would find thousands of these sacs. There was a curious question, however, as to whether the irritation produced was of a mechanical nature, or whether it was of a chemical nature — whether it was due to the excessive fineness of the threads alone, or whether it was not also aided by something of a poisonons nature contained within the sacs themselves. It might, perhaps, be remembered that there was an old trick sometimes played by schoolboys of putting cowage into one's bed which caused a good deal of uncomfortable sensation ; it might be that the effect of the stinging organs in question was of this character, but he thought it also probable that the clear liquid contained in the sacs might have some- 103 tiling to do with the effect, acting somewhat in the same way as that con- tained in the poison glands of the nettle. He did not know, however, that anybody had hitherto furnished sufficient grounds for arriving at a clear con- viction that the effect depended upon either the one or the other, or both causes combined. There was no doubt as to the kind of effects produced, and their severity was in accordance with the size of the thread-cells inflicting them. It was possible to handle Hydro.oa provided with only small thread-cells with impunity, though even these were very formidable to small creatures which came in contact with them. The small fresh water Hydra, for instance, was apparently harmless, but if one of the small water fleas came within reach of its tentacles the effect was most marked and striking. Mr. T. C. White said that Gosse mentioned a very curious instance, show- ing the penetrating power of these minute spines — he cut off with a razor a slice of the hardest skin from the sole of the foot, and presented it to the creature, when he found that even this hard structure was completely pierced through. Mr. A. D. Michael said that this creature was pretty well known on the coast of Cornwall, where the fishermen had the greatest possible dread of it; and he had been assured by them that they sometimes had their arms rendered quite useless for days together after having been stung. The thanks of the meeting were unanimously voted to Mr. Bedwell for his paper. Mr. E. T. Newton read a paper " On a New Method of Preparing a Dissected Model of an Insect's Brain from Microscopical Sections," the paper being illustrated by numerous coloured diagrams, and by the exhibition of the model, and of prepared sections shown under four microscopes in the room. The President, in inviting remarks upon' the paper, observed that the method described by Mr. Newton was one of the most ingenious processes that had for a long time come under his observation. As regarded the brain structure of insects, these questions were all new, and it was very satisfactory to find that the study of them had resulted in the discovery of something more than it was the custom formerly to believe in. Because to him, at least, it was not satisfactory to think that bees and ants, with nothing but a little nervous pulp, were able to do things, apparently with intelligent purpose, which we, with our wonderful convolutions, had some difficulty in imitating. In the case of the cockroach, however, it was a little difficult at first to see what he did with so much brain, at least his capacities did not appear to have been fully recognised, though it might be that perhaps he was of a too retiring nature, or was he possibly "a mute inglorious. Milton'' amongst his fellows of the insect world ? (The President referred to an amusing incident narrated by Mr. Moseley as having occurred on board the " Challenger," illustrating the sagacity and alertness of the Cockroach.) To speak seriously, this method of Mr. Newton's did seem to be a means of bringing before one's mind, not only the structure of insects' brains, but might also be applicable to the study of the highly complicated 194 structure of the human brain. If they could have models of that kind for the study of other kinds of brain structure, he thought it would be highly advantageous, and that knowledge of the subject would be correspondingly helped. A vote of thanks to Mr. Newton for his paper was moved by the President, and carried unanimously. The President announced that at the next meeting Dr. Hudson would deliver a lecture "On Rotifers, with dark field illumination,'' illustrated by transparent diagrams. The proceedings then terminated with a Conversazione, at which the following objects were exhibited : — Section of Clematis Stictodiscus Cheyletus ... Palate of TrocTius cinerarius (?) Section of Laurel leaf Parasite of Secretary Vulture Sections of Brain of Blatta orientalis, showing') Nos. 7, 13, and 20, from a series of 34, and > illustrating Mr. Newton's Model ... J Attendance — Members, 83 : "Visitors, 18. Mr. F. W. Andrew. Eev. H. J. Fase. Mr. H. R. Gregory. Mr. C. Le Pelley. Mr. A. Martinelli. Mr. T. S. Morten. Mr. E. T. Newton Mr. J. Slade. and February 14th, 1879. — Conversational Meeting. } 1 The following objects were exhibited : — Pea Shell... Flour Adulterated with Plaster of Paris Cercopis sanguinoleuta, The Burnet Hopper Head of Bot-fly, Gasterophilus equi, showing rudimentary mouth Section of Seed of Phytelephas macrocarpa Vegetable Ivory, showing cell -cavities and their canals Section of Bone of Tortoise, polarised... Horizontal Section of Foot of Human Foetus . . Crystals of Chloride of Copper Albuminoids in Wheat Young Nymphs of Gamasina (in situ), parasitic") on Rhyphus nigricans, a dipterous insect ) Stephanoceros Eicliornii Geodia Barettii, found at the Base of a Coral ") (Stylaster) ... ... ... ) Spermatophores of Loligo ... Mr. F. W. Andrew. Mr. A. L. Corbett. Mr. F. Enock. Mr. H. E. Freeman. Mr. W. H. Gilburt. Mr. W. Goodwin. Mr. J. J. Hunter. Mr. F. C. Kellow. Mr. A. Martinelli. Mr. A. D. Michael. Mr. G. D. Plomer. Mr. B. W. Priest. Mr. J. Slade. 195 Section of Anamista cocculus ... "s „ ,, Rhipsalis cassytha (double stained) f Transverse Section of Aristolochia sipho f -^ r * *• -"• Ward, (double stained) ... ... ... J Stellate Hairs of Correa ... ... ... Mr. T. C. White. Attendance — Members, 82 ; Visitors, 12. February 28th, 1879. — Ordinary Meeting.* Henry Lee, Esq., F.L.S., Vice-President, in the Chair. The minutes of the preceding meeting were read and confirmed. The following gentlemen were balloted for, and duly elected members of the Club : — Mr. John Bear, Mr. Edward H. Debenham, Mr. H. Epps, Dr. C. T. Hudson, Mr. James H. Mann, Mr. James Menzies, Mr. Henry Nesbitt, and Mr. W. Venables. Four gentlemen were proposed for membership. The Chairman said that it was his painful duty to announce the death, since their last meeting, of a former President of the Society, Mr. Peter Le Neve Foster. He had died in harness, and quite unexpectedly ; he left his work as usual, went home, and then, being seized by a fatal ill- ness, he passed away. He was 70 years of age, and had therefore reached the " three score years and ten " allotted to man ; but time passed so rapidly, and so juvenile was he in his manner, that few would have regarded him as being so far advanced in life. To many of those present he was well known, and to all such it would be unnecessary to say that he would continue to live in their kindly remembrance and respect. Mr. T. C. White rose to suggest that it would be consistent with the character of the Club to pass a vote of condolence with the family of Mr. Foster in connection with his lamented decease. The Chairman said it would be most perfectly in accordance with his own views, and he felt sure that the suggestion would be fully approved by the Society. Mr. T. C. White then formally moved a vote of condolence to Mrs. Foster and family, which, having been seconded by Mr. A. D. Michael, was put to the meeting, and carried unanimously. The following list of donations to the Club was announced : — " Proceedings of the Royal Society "... ... from the Society. " Journal of the Royal Microscopical Society "... „ „ ,, " Proceedings of the Belgian Microscopical ~) _ f » >> !> Society' ... ... ... ) " Proceedings of the Chester Society of ) Natural Science" ... ... ) Held in the Mathematical Theatre, University College. 196 Paper by Mr. Kitton, " On Diatoms," reprinted") n ,-, . ,, from " Journal* R. M. S." ... ) " American Quarterly Journal of Microscopy "... in Exchange. " Science Gossip " ... ... ... ... from the Publisher. " Journal of Anatomy and Physiology " ... „ „ „ Pakenham Edgworth's Work on Pollen ... „ Mr. By water. '• Meteorology of Croydon" ... ... ... „ Croydon Mic. Club. "American Journal of Microscopy" ... in Exchange. " American Naturalist " ... ... ... „ "Annals of Natural History" ... ... by Purchase. The thanks of the Club were unanimously voted to the donors. The Chairman then called upon Dr. Hudson to favour them with his ex- planation of the subject of the illumination of Rotifers on a dark field. (An abstract of this communication will be found at p. 164.) The Chairman expressed his regret that their President had not been able to be with them on that occasion, for no one who had not made a complete study of these organisms could do complete justice to the subject. Dr. Hudson was one of their best authorities on Rotifers, and was, at the same time, one of the clearest demonstrators he had ever had the pleasure of listening to, while his method of illustration could only be characterised as accurately beautiful and altogether superb. He had the greatest pleasure in proposing a vote of thanks to Dr. Hudson for his very admirable lecture, and for his kindness in coming all the way from Bristol to deliver it, and to show them his very beautiful diagrams. The vote of thanks having been put to the meeting and carried by acclamation, The Chairman called upon Dr. Matthews to give an explanation of the Micro-Megascope, a new method of showing microscopic objects, irrespective of size. (See p. 167.) A vote of thanks to Dr. Matthews was unanimously passed, the Chair- man observing that he was sure they would welcome anything which added to the enjoyment of the microscope, even if only in a toy form. Mr. J. D. Hardy thought that, in the interests of the Club, he ought to mention that Mr. Jas. Smith had, he believed, exhibited an identical arrangement, or certainly one very much like it. He had shown it at his i the speaker's) house, and also at the Hackney Microscopical Society, but he did not claim it at all as his original idea, but, on the contrary, he said he got it from some Amei'ican paper. He certainly was enabled to show transparent objects as well as opaque ones, and was able to diminish them, and also to magnify them up to a half -inch objective. It was just possible that Dr. Matthews might have hit upon some improvement upon it, and he only regretted that Mr. Smith was not present to speak for himself. He thought, however, that for the credit of the Club he ought to mention that the idea was not a new one. The Chairman said that it was quite right and necessary in the interests of science that priority of discovery should be frankly 197 challenged and properly established. It was possible, as the last speaker had said, that Dr. Matthews might have accidentally hit upon an idea that had occurred to some one else, but it was impossible to suppose for an instant that Dr. Matthews would bring before them as his own discovery, and describe to them the process of dedactive reasoning by which he per- fected that discovery, knowing that his invention had been practised and published by another. Before Dr. Matthews offered an explanation, he was certain that either this would prove to be one of those cases of simultaneous discovery which sometimes occurred, or that the two processes were not identical. Mr. Frank Crisp said he thought the only rule they could follow was that of the botanists — that no claim to priority could be recognised unless upon the ground of publication. Mr. Hardy explained that he had no intention of making the slightest imputation in the matter; he only thought it would not be quite the thing for this idea to be claimed as something new, originating from the Club, whereas it had already been published in an American paper. Dr. Matthews said that when he was first informed that Mr. Smith had brought out something of the kind, he wrote to him on the subject. Mr. Smith kindly called upon him, and then described the method he had adopted, and made the same disclaimer as to the originality of his idea. Mr. Ingpen remembered that Mr. James Smith certainly said that Dr. Matthews' use of the principle was different from his own, the original idea of which he had taken from some American publication. The principle had, of course, been known ever since the microscope had been in use ; it was, in fact, that of the terrestrial telescope ; the aerial micrometer, and the erecting glass also more or less involved the same idea. He had recently heard that Mr. James Smith had some time since exhibited opaque objects in this manner, and he wished that he had known of it at the time, because he would then have given it all the publicity in his power. So far as the remarks of Mr. Hardy were concerned, he did not think that any invidious- ness was intended, and he felt sure that if Mr. Jas. Smith had been present he would have been the first to acknowledge any merit on the part of what Dr. Matthews had devised, and to thank him for bringing it before the Club. Notices for the ensuing month were then given out, and the meeting adjourned to the Library for the usual conversazione, at which the follow- ing objects were exhibited : — Organs of Mouth of Sand Wasp (Ammophila \ sabulosa), retaining natural form and colour \ ]y[ r< -p. Enock. of the various parts ... ... / Photograph to illustrate the principle of the) ^ j k j att j iewg Micro-Megascope ... ... j Grains of Aleurone in Bean of Castor Oil Plant... Mr. F. H. Ward. Attendance — Members, 115 ; visitors. 32. 198 Conversazione. The Conversazione of the Club was, by the kind permission of the Council of University College, held on Friday, the 14th of March, and was attended by about 1,050 persons. This number was smaller than was anticipated, the reduction being probably due to the unfavourable weather, and to the Conversazione being held in Lent. One hundred and fifteen microscopes were brought by members of the Club ; seventy by members of the South London, the Croydon, the Syden- ham, the Greenwich, the New Cross, the Tower Hill, and the Hackney Societies. The bays of the library were also, as on previous occasions, filled with the best productions of the leading London opticians. In addition to the display of microscopes were the following attractive features : — A Natural History Lecture, entitled " Curious Houses and Queer Tenants," delivered by Mr. W. E. May, in the Mathematical Theatre. An exhibition, by Mr. A. C. Cole, of a large number of physiological and pathological specimens by means of one of Mr. Browning's " Lantern Microscopes," kindly lent by him for the occasion. An exhibition by Mr. G. J. Smith (for Messrs. How and Co.) of the oxy-hydrogen Kaleidoscope, experiments with polarized light, photographic transparencies, &c. A number of scientific diagrams were kindly lent by Messrs. Hardwicke and Bogue, and were shown in the Museum. A selection of operatic and other music was performed in the Flaxman Hall by a very effective band, under the leadership of Mr. B. W. Barratt. The following is a list of the objects exhibited by our members and those of the various Societies above-mentioned, so far as could be ascertained from the table-tickets : — Tree-bug (Tingis crassicornis) ... ... Mr. T. G. Ackland. Spicules of Cucumaria pentactes ... ... Mr. Wm. Adams. Sheep Tick ... ... ... ... Mr. W. Addis. Section of Carrot (not mounted) „ „ Human Hair, polarised Snake-head Coralline, in situ ... ... Mr. C. Allison. Eye of Lace-wing Fly ... ... ... Mr. G. Alstone. Crystals from Wine (Claret) ... Section of Pear, showing Baphides . . . Sand from the Salt Lake, Utah ... ... Mr. A. Arch. Lung of Kitten ; Sections of Human Scalp,) Tongue and Kidney ... ... j Wing-case of Beetle ... ... ... Mr. H. A. Auld. Mosquito; Spiracles of Acilius sulcatus, &c. ... Mr. J. Badcock, Jun. Grouped Polycistina: Young of Anodon^ ' ' . .?,. . [ Mr. E. S. Balchin. cygneus ; Baphides in skm of onion ) Volvox glolator ; Stentor, in fission, &c. ... Mr. A. H. Barker. Mr. W. Adkins. } Mr. F. W. Andrew. Mr. A. Ashbridge. 199 Fungus on Fly ; Peacock Copper Ore Saw of Saw-fly ; Section of Screw Pine Coneatus tamarissi ; Skin of Dog Fish Tick of Cobra, India ; Leaf of Deutzia, &c. Pollen of Orange Lily Melicerta ring ens ; Vorticella Section of Tail of Puppy, injected ... Spines of Star fish, arranged Transverse Section of stem of Pepper Anther and Pollen of Lavatera rubra Stephanoceros ; Spongilla Jluviatilis ... Rotifers ... Section of Labrador Spar, polarised ... Section of Whalebone ; Section of Granite Sheep Tick Head of Crane Fly ; Parasite of Beetle") (Gamasus coleoptratorum) ..• j Spores of a rare British Fungus (Tetraploa aristata) ; Parasitic Leaf-Fungus (Micro- sphcsra pulchra) Pollen of Acacia dealbata (?) Cristatella rriucedo ; Volvox globator ; Cono- chilus volvox ; Lophopus cristallinus Scales of Butterflies arranged as a Bouquet Grouped Polycistina ; Spicules of Gorgonia ; Stem of Clematis, double-stained Shell of Haliotis splendens ; Ceramium acan- thionatum, &c. Feathers of Humming Birds Moth's Wing Calcareous Bodies from Shells of Echinus Transverse Section of Sarsaparilla ; Mid-rib of India rubber Plant, double stained Transverse Sections of Dracaena and Clematis,^ double-stained ... ... ) Palate of Limpet ... Larva of Ephemera Arachnoidiscus, in situ ; Isthmia nervosa Wing of Urania; Ichneumon, &c. Feathers of Humming Birds Thorax of Diamond Beetle ... Platino-cyanide of Magnesium ; Echinus spine; Section of Pearl Sections of Teeth ... Polycistina, grouped ; Section of Jaw of Mole,") polarised ... ... ... ) 1 ] Mr. J. A. Batchelor. Mr. J. Berney. Mr. W. A. Bevington. Mr. E. G. Bishop. Mr. W. Bishop. Mr. J. W. Brigstock. Mr. W. J. Brown. Mr. G. Browne. Mr. E. R. Budden. Mr. M. Burgess. Mr. A. Butt. Mr. J. W. Cafe. Mr. G. Carr. Mr. J. A. Clark. Mr. Joseph Clark. Mr. H. H. Coel. Dr. M. C. Cooke. Mr. A. C. Conhead. Mr. W. G. Cocks. Mr. F. Coles. Mr. G. T. Collingwood. Mr. A. L. Corbett. Mr. T. Crossfield, Jun. Mr. J. H. Crossland. Mr. R. E. Crossland. Mr. E. A. Crowley. Mr. P. Crowley. Mr. T. Curties. Mr. E. Dadswell. Mr. G. G. Daniel. Mr. G. Dannatt. Mr. T. W. Dannatt. Mr. W. Dannatt. Mr. T. D'Aubeny. Mr. A. Dean. Mr. H. H. Dobson. 200 Dro sera rotundif olia, &c. Chrysaora of Hydra tuba ; Eggs of parasite^) of Peacock ... ... ••• j Group of Vorticella ; Plumatella repens Surirella gemma, Pleurosigma angulatum, in""\ Balsam, shown with Zeiss' 1-12 inch oil- C immersion objective and Abbe's condenser J Transverse Section of Aristolochia sipho,\ double-stained ... ... ) Sections of Hypersthene, Green Avanturine,) and Egyptian Agate, polarised ... ) PMlodina roseola ... Campanularia gelatinosa ; Fructification of Fern Balanus balanoides (alive) Jaw of Spider ; Spicules of Synapta vittata Internal Silicious casts of Foraminifera ; Tongue and Lancets of African Tabanus Hydra viridis ; Baphniapulex Sugar Mites Scalariform Vessels in stem of Fern; Section) of stem of Sarsaparilla... ... ) Frond of Polystichum angulare ; Leaf of } } Citrus anrantium Section of Laurel Leaf, stained; Pollen of) Evening Primrose ; Protococcus nivalis ) Parasite of Flying Fox (Nycteribia) ... Wood Spider Tooth of Saw-fish ; Jaw of Cat ; Bone of Tor- toise, &c. Transverse Section of Mahogany, polarised Gizzard of Cricket; Mignonette; Antennee of Emperor Moth... Foraminifera Globigerina Ooze (2,000 fathoms) ; Indian) Diatoms; Spicules of Sponge ... ) Carchesium ; Gills of Mussel Chlorate of Potash ; Platino-cyanide of Mag-) nesium ... ... ... ) Chloride of Cadmium; Platino-cyanide of Mag nesium; Nitre, &c. Proventriculus of Starling ... Bicetlaria ciliata ; Dan&a alata ; Teeth of Acanthurus ; Echium violaceum ... Fern leaf, double stained Hairs of Sea Mouse 1 } Mr. T. R. Duggan. Mr. C. G. Dunning. Mr. F. East. Dr. Edmunds. Mr. C. Emery. Mr. H. A. Erlebach. Mr. T. D. Ersser. Rev. H. J. Fase. Mr. F. Fitch. Mr. J. Flower. Mr. H. E. Freeman. Mr. G. Gardiner. Mr. F. W. Gay. Mr. E. George. Mr. W. H. Gilburt. Mr. H. G. Glasspoole. Mr. J. W. Goodinge. Mr. C. H. Goodman. Mr. W. Goodwin. Mr. H. R. Gregory. Mr. W. Gregory. Mr. H. F. Hailes. Mr. E. Hardy. Mr. J. D. Hardy. Mr. F. Harrisson. Mr. H. T. J. Hart. Mr. R. Headley. Mr. F. W. Hembry. Mr. F. H. P. Hind. Mr. G. Hind. 201 } 1 } Spores of Fern Arranged Butterfly Scales ; Section of Human") Kidney ... ... ... ) Cyclosis in Vallisneria, ; Platino-cyanide of Magnesium; Section of Lower Jaw of Mole... Skin of back of Horse Diatoms from the Wandle, Stour and Mole ; Forarninifera, &c, from Sponge ... Section of Human Muscle, Injected ; Colorad Beetle; Palate of Snail Young Salmon (three weeks old) Hypnurn rutabulum Platy cerium alcicome ; Sections of Chalcedony") and Sun-Stone, &c. ... ... ) Section of Brake (Pteris aquilina) „ ,, Grape Vine Stem Spines and Plates of Brittle Star; Section of Rattan Cane ... Polycistina; Section of Bamboo Sections of Teeth of Leopard and Ass ; Seeds of Nemesia versicolor, &c. ; Whole Spiders, &c. Eggs of Parasite of Pheasant; Eggs of Poly-~) ommatus alexis ... ... j Alpine Insects; Iridescent Scales on body of Moth; Batrisus formicarius Pollen of Garden Mallow ; Cholesterin polar ... Fermentation of Malt Liquor and formation") of Yeast ; Cuticle of Geranium ... ) Feather of Sugar Creeper ... Sections of teeth of Hake and Pike ; Scale of Pike Larva of Lobster ; Head of Silk- worm Moth ... Crystals of Silver; Section of Laurel Leaf ... Objects shown by the " Micro-megascope " Crystals of Common Salt and Nitre ... Mucous Membrane of Diphtheria Tegeocranus lotus, Nymph and Mature form ; Gamasus crassipes ; Verruca stromia, an Acorn Barnacle "What's his Name?" Sections of Stems of Modecca tamifolia and) Argyria multifljra ... ... j Parasite of Ox ; Wing of PJialauna Butterfly . . . Sections of toe and nose of White Mouse, } Colon of Cat ; HumanMolar tooth ; Tongue > of Puppy ... ... ... J Mr. C. W. Hovenden. Mr. W. S. How. Mr. D. Howard. Mr. W. H. B. Hunt. Mr. W. Ingrams. Mr. F. Inskipp. Mr. S. Israel. Mr. E. Jaques. Mr. F. C. Kellow. Dr. R. C. Kibbler. Mr. E. Kiddle. Mr. F. J. Kitsell. Mr. J. R. Leifchild. Mr. C. Le Pelley. Mr. R. T. Lewis. Mr. T. M. Loftus. Mr. H. Long. Mr. F. McKenzie. Mr. J. B. Magor. Mr. H. K. Marriott. Mr. A. Martinelli. Dr. Matthews. Mr. J. Menzies. Mr. G. A. Messenger. Mr. A. D. Michael. Mr. A. Milledge. Mr. H. Morland. Mr. T. S. Morten. Mr. W. J. Nation. 202 Sea Cucumber, from Torquay Section of head of Wasp Stephanoceros Eichornii Polyzoa from the Crag Head of Crane Fly Copper; Scale of Adder, polarised ... Foot of 'Bytiscus ; Tongue of Blow-fly Vorticella ; Conochilus volvox Proboscis of Blow-fly ; Wing of Burnet Moth ... Spinnerets of Spider; Yonng Salmon... Electra verticillata ; Leaf of Rhododendron) calaphytium ... ... ... ) Larva of Gnat; Cgclops qitadricomus ; Mites \ in Cheese ... ... ... J Larva of Ephemera Arranged Butterfly Scales; Platino-cyanide") of Barium; Lower Jaw of Mole ; Section > of Lamprey ... ... ••• ) Photographs Hydroid Zoophytes (living) ... Diamond Beetle ; Spicules of Synapta ; Leaf ^ Insect ; Pond life .. ••• ) Gizzard of Flea ; arranged Diatoms ; Parasite") of Flying Fox ... ... ) Stomach of Frog ; Antheridia of Nitella Metzgeria f areata in fruit Leg of Cyphus germari; Diatoms from Penang Batrachospermum moniliforme and B. atrutn,' mounted in spirit in 1866 ; Diatoms in S ft U . • • » • ■ • • • Microphone by Blakey's patent Battery ; a rare") Fossil Fish in Amber ... ... ) Section of Stem of Water Lily Arranged Diatoms... Mouth of Beetle ; Frog -hopper Cyclosis in Nitella ; Stephanoceros Parasite of Cat {Tricodectes) Section of Schorlaceous Granite ; of Crustacea ... Titanic Sand from New Zealand ; Echinus Spine ; Brecciated Jasper ; At lautic Soundings ... ... ) Carchesium polypinum Diatoms ; Hairs on leaf of Dentzia scabra Section of Lung of Smothered Child ; Human Lung in health 1 Collection") J Section of 1 } Mr. Jas. Nelson. Mr. E. T. Newton. Mr. J. Offord. Mr. C. P. Ogilvie. Mr. J. C. Oswald. Mr. S. Overton. Mr. H. R. Owen. Mr. F. Oxley. Mr. S. Palmer. Mr. C. N. Peal. Mr. H. W. Peal. Mr. G. Pearce. Mr. A. C. Pearcy. Mr. R. A. Potts. Mr. T. H. Powell. Mr. B. W. Priest. Mr. T. Purdue. Mr. G. E. Quick. Mr. J. W. Eeed. Mr. F. Reeve Mr. W. W. Eeeves. Dr. Reilly. Mr. T. Rogers. Mr. H. J. Roper. Mr. J. Rowlett. Mr. Jas. Russell. Mr. Jos. Russell. Mr. T. D. Russell. Mr. S. B. Saffery. Mr. W. L. Sergeant. Mr. E. Scargill, Jun. Mr. W. L. Scarr. 203 Trichina spiralis, in Man, Pork, and brain of") ^ ^ j Scofield. Rat 1 '} } Coneatus tamarissi ; arranged Butterfly Scales Pond life — Hydra viridis ; Larva of May -fly ... Entomological Specimens; Eggs of Parasites - } of Mallee Bird and Reeves Pheasant ; ' Eggs of Chalk Hill Bine Butterfly and j House-fly, &c, &c. ... ••• J Spiniferous tubercles of Lingthorn ; Cladonia~) pyxidata ... ... ..• ) Sections of Seed Vessel of Antirrhinum ma jus Pollen of Mallow ; Wing of Peacock Butter- fly; Polycistina Circulation of blood in tail of Newt; Larva) of Ephemera ; Living Entomostraca ) Ilydatina senta ; Leaf stalk of Ficns elastica ; Oxalate of Potash and Chromium, &c. Hydra viridis ; Spicules of Gorgonia, &c. Blossom of Hazel ; Fossil plant-sections Coal ... Leaf of Deutzia scabra ; Echium glabrum Lepisma ; Podura ; Larva of Centipede (alive) . . Stem of Japan rush, stained ; Larva of Tiger Moth... Palate of Whelk, polarised ... Ballia callitrica, an Australian seaweed Hydra fvsca Animal and Vegetable Parasites of the human ~) skin and hair ... ... ... ) English Moths — preserved Larvae and life-^ histories ... ... ... j Plumatella hatching from Statoblasts ; Qorethra Pond Life Oil glands of Lavender ; Qranictis ceterach . . . Aulacodiscus Margaritaceus (10 rays) Micro-rulings on glass and steel ; simple form ) of Aquarium Mioroscope ... ) Section of Eye of Drone-fly; Salivary glands "i of Cockroach... ... ... j Jaws of Cockroach ; Tongue of Bee ; Wing of I Alorpho cypris ... ... ... j Daphnia pulex ; Stephanoceros Eichornii Root of Lime ; English Diamond Beetle ; Elm ) Moth ... ... ... j Shells from Turkey Sponge, &c, &c. ... Pond Life (Cyclops, &c.) Mr. R. Sedgwick. Mr. H. L. Sequeira. )■ Mr. J. S. Sequeira. Mr. W. Short. Mr. J. C. Sigs worth. Mr. J. J. Simmons. Mr. E. Simpson. Mr. T. Simpson. Mr. W. Smart. Mr. Alpheus Smith. Mr. Jas. Smith. Mr. J. A. Smith. Mr. R. A. Smith. Mr. W. L. Smith. Mr. W. S. Smith. Mr. J. H. Stanley. Mr. Jas. Startin. Mr. F. Stewart. Mr. D. J. Stuart. Mr. E. B. Stnrge. Mr. E. D. Suter. Mr. K. J. Tarrant. Mr. Washington Teasdale. Mr. T. Terry. Mr. J. Thompson. Mr. W. A. Tinney. Mr. W. Trickett. Mr. A. Topping. Mr. W. C. Vernon. 204 Selected Diatoms ... Sponge; Illustrations of the Structure of) Dysidea frag His ... ... \ Section of human scalp and small intestine ; ] Trichina spiralis, &c, &c. ... J Cheese Mites ; Foraminif era from Post-Glacial ] Sands ... ... f J Section showing the Junction of Mistletoe") and Apple-stem (double stained)... j Section of Equisetum (double stained); Pupa') of Stylops emerging from abdomen of C Wild Bee ... ... ... j Wing of Plume Moth; Spiracle of Dytiscus\ marginalis ... ... ... j Head and Leg of Spider; Proboscis and) Antennse of Drone- fly ... ... j Arranged Diatoms ... Wrangelia multifield; Lometitaria articulata) (Marine Algas)... ... ... j Campamrtaria (Marine Zoophyte) ; Stem of Clematis vitalba ; Young Trout ... Capsules of Funaria ; Spines of Starfish Arranged Diatoms; Crystals of Manganese .. Transverse section of Bamboo Cane, polarised Thistle Gall-fly (Trypeta cardui); Three| spined Stickleback, polarised ... j Mr. J. W. Walker. Mr. J. G. Waller. Mr. W. Walters. Mr. S. Warburton. Mr. F. H. Ward. Mr. A. Warner. Mr. H. R. Warrington. Mr. F. L. Waterman. Captain Weatherley. Mr. W. West. Mr. T. Charters White. Mr. G. Willcocks. Mr. J. R. Williams. Mr. C. Willmott. Mr. F. Wood. Amongst the large number of professional exhibits, the following claim Bpecial notice : — Mr. Bailey — Students' Microscopes; Improved Portable Folding Micros- copes ; a Series of Rock and Mineral Sections, &c. Mr. Baker — " New Model," and Binocular Microscopes, &c. Messrs. R. and J. Beck — Improved large-sized Portable Microscope, with rotary stage and Iris diaphragm ; " Economic " Microscope ; " Popular " Microscope, &c. Mr. Browning — Microscopes with Stephenson's Binocular Arrangement ; New Miniature Microscope ; Micro-Spectroscopes, &c. Mr. Crouch — New " Histologist's " Microscope, with special 1-2, 1-5, 1-6, and 1-10 inch objectives; "Alpha" School and Botanical Microscopes, &c. Mr Enock — Insects mounted without pressure, showing their internal structure undistorted. Messrs. Home and Thornthwaite — Portable Equatorial Reflecting Tele- scope ; Polarising Kaleidoscope ; Ackland's Dioptric Optometer, &c. Messrs. Hunter and Sands — A Collection of Histological and Pathological specimens shown under several microscopes. Messrs. How and Co. — Microscopes showing a series of specimens illus- trating Roch-structure ; New Miniature Mici'oscope Lamp. 205 Mr. G. H. King — Freshwater Aquaria with Gold-fish ; Microscopical Aquaria with Daphnia, Hydra, Diatomacece, &c. Mr. Moginie — Travelling Microscopes, and Portable Lamps ; Colorado Beetles ; Arranged Groups of Insect-scales ; Ancient Glass from Cyprus, &c, &c. Messrs. Murray and Heath — Students' Microscopes, Binocular and Monocular; Pocket Seaside Microscope. In the Museum — Revolving Album; Praxinoscope ; Cabinet Stereoscopes, Graphoscopes, &c. Messrs. Pickard and Curry — A Series of Preparations, illustrating the Histology of the Human Eye. Messrs. Powell and Lealand — Cyclosis in Vallisneria, with l-16th Immersion Objective and Patent Binocular; Podura Scale, with l-8th Objective; Volvox globator. Messrs. Ross and Co. — New Ross-Zentmeyer Microscopes ; Various other forms of Microscope ; Case with complete set of Apparatus. Mr. Swift — " Challenge " Microscope, with patent spiral rack motion for coarse adjustment ; Travelling Portable Microscope ; New Camera Lucida, &c. Messrs. Watson and Son — " Standard " Binocular Microscope ; Large Binocular and Small Medical Microscopes, &c. Ordinary Meeting. — March 28th, 1879. Dr. J. Matthews, F.R.M.S., Vice-President, in the Chair. The minutes of the preceding meeting were read and confirmed. The following gentlemen were balloted for, and duly elected members of the Club: — Mr. F. E. Bird, Mr. Francis Hallowes, Mr. C. E. Hawkins, and Mr. David Smith. Six gentlemen were proposed for election. The following Donations to the Club were announced : — ■ " Proceedings of the Royal Society"... ... ... from the Society. " Proceedings of the Botanical Society of Edinburgh " „ „ " Proceedings of the Geologists' Association " ... „ Association. " The Midland Naturalist " ... ... ... ... in exchange. " The Analyst" from the Editor. " Proceedings of the Belgian Microscopical Society " „ Society. " Science Gossip " ... ... ... ... ... ,, Publisher. " The American Journal of Microscopy " ... ... in exchange. " The Annals of Natural History " ... ... ... by purchase. 12 Slides of Stained Vegetable Tissues from Mr. F. H. Ward. 1 Slide of " Glyciphagvjplumiger".., ... ... „ Mr. A.D.Michael. 4 Slides of Richmond and Pittsburgh Deposits 3 " " 5 * (. (per Mr. A. Allen). 206 The thanks of the Club were unanimously voted to the donors. The Secretary read the report of The Soiree Committee. Dr. M. C. Cooke read a paper " On the Dual Lichen Hypothesis." The Chairman said he had no need to invite their attention to the very admirable paper which they had just heard, feeling sure that it had already commended itself to them. There were so many points of interest in it that he hardly knew which to refer to ; but it had struck him that Dr. Cooke's remarks as to the selective power of insects did not bear very strongly upon the argument, because it might be said of them that " what was one man's meat was another man's poison." Dr. Cooke thought that the Chairman had not quite understood his reference to insects — what he meant to say was that if these two classes of plants were identical, why did not the same insects attack both of them ? If these insects attacked all fungi, then why did they not attack the lichens also, if it were a fact that the lichens were of precisely the same nature ? Mr. Charles Stewart said he felt it somewhat presumptuous on bis part to speak at all upon this subject after what they had heard from Dr Cooke, but inasmuch as he had the honour of first bringing this theory before the notice of the Club, he thought that perhaps he might be permitted to make just one or two remarks. In the first place he would submit it as being an open question as to whether a specialist was really the person most likely to take a fair view of what ran counter to his own ideas ? Secondly, it seemed to him that there had been two con- tradictory statements made upon the subject. It had been said that from the Hyphce were developed the Gonidia, and if this were shown to be the case, it would go very far to overthrow the hypothesis. But there was also another statement, that the spores developed in the Asci of a lichen, although they would germinate would not continue to grow, but would form merely an abortive attempt at germination without the assistance of certain green granules to which attention had been already called. The theory was that this was a case of dual existence, and he must say that it was a theory naturally suggestive to a scientific mind. If any one looked at the Asci of the Lichens, and looked also at the Gonidia, although there might not be an absolute identity, yet there was, he thought, a very close resemblance between the former and the Asci of Fungi, and between the latter and Alga3 ; and it should not be forgotten that it had been said that any one of the Gonidia could be caused to go through the life history of the Alga, from which it was supposed to have been derived. For his own part he thought it was at present a balanced question, and one which whilst it was as yet unsettled, was one not to be settled by big words. Dr. Braithwaite said he had been very much struck by the theory of Schwendener when first it came under his notice ; he read it carefully and with very great interest, but yet somehow it never seemed to bring with it a conviction of its correctness. Most things brought a kind of convic- tion with them, but somehow to his mind this did not. One thing especially seemed unsatisfactory, and that was, how should these lichens maintain their habits and characters if their existence was explained by this theory. 207 Dr. Cooke had treated the subject so exhaustively that he felt bound to admit that whatever balance of opinion he might have had on the other side had been transferred after hearing this very able paper. Mr. Frank Crisp wished to enter a mild aud friendly protest against the way in which Dr. Cooke had spoken of such men as Stahl and Schwendener. They were men of great respect in their own country, and he thought it was hardly well for it to go forth that they had been referred to slightingly by any one connected with the Quekett Club. Mr. A. D. Michael said there was just one little point to which he should like to call attention, and that was that he thought the definition given of parasitism was rather liable to lead to error. If they were to take it that the parasite lived necessarily at the expense of the organism upon which it was parasitic, then some other term must be found for those which were always found in connection, and which did not live at the expense of each other. Almost every bird had Dermaleiclii upon it, and if we were to trust the authority of the best observers Dermaleichus is not injurious to the bird ; but also living on the bird was found a Cheyletm, which devoured the Dermaleichus. Here, then, were two distinct classes of creatures living upon the same organism without being in any way injurious to it. If these were not parasitic they must find some other name for those which lived on others without drawing their sustenance from them. Dr. M. C. Cooke said he had very little to say in reply to the observa- tions w T hich had been made, and indeed he thought very little was necessary. He thought that Mr. Michael had made a man of straw and then knocked him down, probably not having clearly understood his meaning. Certainly Dermanyssus was a parasite, but pai'asites were not necessarily injurious to the creatures on which they lived. His remarks, however, referred to the parasi- tism of fungi only — to which he believed his observations correctly applied. He thought that his friend Crisp had made a slight mistake — he did not call Stahl any names, because he knew him to be a learned professor, who had done much good work in his time ; therefore he had nothing disrespectful to say of Stahl. He pleaded somewhat guilty, however, of using rather epithetical terms of Schwendener. He knew nothing of Sc