^^ie*,'*' i»-M «,.« s'Vi" ■■ij*si-^?jA*--.'< «••* ' ■:«.., \ \ ■««« ^N - ^ s, V ^,\s\ \N^'« '\0 ^^ > ^*',^-,^ mmEmjAi FOR THE HARRIS & POWER The original of tliis book is in tine Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/details/cu31924031276003 Cornell University Library arV18396 Manual for the physiological laboraton 3 1924 031 276 003 olln,anx MANUAL FOE THE PHYSIOLOGICAL LABORATORY. BY VINCENT HAKRIS, M.D. (Lond.), M.K.C.P., Demonstrator qf PhyHology at, and Casualty ^Physician to, St. SariholomeioU Bbspttal ; Asalttant PAyatctan to the City of London HoapWal ■ for DUeasea of t/te Cheat, Victoria Park ; etc.. D'ARCY POWER, B.A., Oxon., Aaatstant Demonatrator of Physiology at St. BartholoTnew^a Uoapital; Late Exhibitioner in Natural Science of Exeter College, Oitford, etc. NEW YORK: WILLIAM WOOD & COMPANY. 1881. PEEFACE. It has been customary for several years to issue to the class of Practical Physiology ia St. Bartholomew's Hospital papers containing a short account of the histology and chemistry of the various organs, together with the methods employed in the preparation of the tissues for the micro- scope. The gradual increase in the number of these papers has induced the authors to coUect and publish them, as they have found that in a large class it is almost impossible to to teach practical histology without some definite text-book as a basis. The excellent manuals of Foster and Langley, Schafer, and Eutherford, possess the objection that they are some- what too elaborate for the ordinary student, whilst they do not contain, any epitome of histology — an omission which in the opinion of the authors greatly detracts from their utility. This work may therefore prove in some respects more useful to the classes of practical physiology now established in the various medical schools, than those more complete ones which have just been mentioned. Much of the histology has been taken from the works of Klein, Prey, Eanvier, Strieker, and Schafer. 4 PREFACE. At some future time the Authors hope to publish an account of the chief physiological instruments based on the same plan, with the methods for employing them. The Authors beg to return thanks to Mr. Morrant Baker for many valuable suggestions ; to Dr. Klein, F.E.8., for revising part o^ the histology ; to Dr. Eussell, F.E.S., for permission to publish the chemical memoranda, compiled under his direction ; and to Mr. J. W. Groves, of King's College, for allowing free use to be made of his eminently practical paper on "Hardening and Staining, etc.," recently read before the Quekett Microscopical Society. VINCENT HAEEIS. D'AECT POWEB. TJPPEE Behkblby Stbbet, W., Mcuroh, 1880. INTEODUCTION. It is seldom possible to obtain good results if tissues be examined under the microscope without previous prepara- tion. It has been found necessary, therefore, to use various methods which subserve the purposes of — (1) Hardening or Softening, ' (2) Cutting and Teazing, (3) Staining, (4) Mounting, before submitting the structure to examination. "We propose devoting sections to each of these processes before treating of the tissues individually. Examination of fresh tissues, when necessary, may be done in — Normal saline solution,, -whiGh is a '75% solution of chloride of sodium. Blood serum. Aqueous humour of the eye. Iodised serum, which consists of serum to which a little iodine has been added to preserve it. 1. Haedening or Tissues is accomplished either by (1) Various hardening fluids, (2) Freezing, a method which is applicable to microtomes only, and of which we shall treat at page 9. The hardening fluids contain as a rule some of the pre- fa METHODS. parations of chromium, of which the most usual are chromic acid, bichromate of potassium, and bichromate of ammonium. (1) The solution which is of most general use is a mixture of chromic acid and spirit j it is thus prepared : — R Chromic acid ^% solution {i.e., containing 1 grm. in 600 CO.), 2 parts. Methylated spirit, 1 part. It may be modified by taking equal parts of 0'5% solution of chromic acid, and of methylated spirit. This fluid produces its effects in a very short time — i.e., about seven to ten days. (2) Bichromate of potash is very frequently used in solu- tions the strengths of which vary from 1% to 5% : the best is the 2% solution, and this, if changed ever)' four days, hardens tissues in a fortnight. (3) Bichromate of ammonia is specially used for hardening the brain and spinal cord, ia solutions of 5% strength. (4) Muller's fluid is made thus : — Potass, bichromat., 2 grms. SodsB su^phat., 1 grm. Aq. destiUat., 100 cc. (5) Methylated spirit alone is frequently employed. (6) Absolute alcohol of specific gravity 0*795 is the most rapid hardening fluid. It is not often used, on account of its expense, and because it has a tendency to produce shrinking of the tissue hardened. Osmic acid, 1%, gold chloride 0'5%, and picric acid (satu- rated solution), are sometimes used as hardening re-agents, when the tissue is required to be hardened and stained simultaneously. Directions for hardening. — Never use anything but fresh tissue. Out the tissue into pieces, about the size of a hazel- nut, with a sharp razor. Do not wash with ivater, but mTEODUCTION. 7 if it be necessary to get rid of any foreign body, allow a small stream of a weak solution (•25%) of potass, bichromate to run upon it from a wash-bottle. Place the cut pieces into a large excess of the hardening re-agent in a stoppered bottle, which should be kept in a cool place. , Change the hardening re-agent frequently — e.g., the chromic acid and spirit solution on the second, fourth, and seventh days. In all cases, in a week to ten days remove the specimens to spirit to complete the hardening. Softening fluids. — Certain tissues, especially bone, have to be softened before they can be conveniently cut into sec- tions for the microscope. The usual fluid is a solution of liydrochloric acid, from 2% to 3%, or a mixture of nitric and hydrochloric acids. Tendons and other such tissues have to be placed in a solu- tion of potass, bichromat., 2%, in order that the cementing material maybe sufficiently softened to allow of teazing with needles. A saturated solution of picric acid is recommended for softening, and at the same time for preparing teeth. 2. CIITTIN&. The most usual way of obtaining thin sections of hardened tissues is by (1) hand-cutting with a sharp razor; but sections may also be cut (2) with machines called microtomes, or (^3) with a Valentin's knife. (1) Cutting sections ly hand. — In cutting a small piece of tissue it is customary to embed it in a wax mass of some kind. For this purpose small paper boats may easily be formed {see Appendix), or a little square tin box with a removable bottom may be used to hold the melted material. O METHODS. The tissue is held upon a needle mounted in a handle, and is covered over with a layer or two of the melted wax, which is allowed to harden upon it. When the wax mass is cooling, the piece of wax-enveloped tissue is placed in one end of the boat, and is then covered over with more melted wax, and the whole allowed to harden. When cool, the wax is remt)ved from the paper or tin boat, and the tissue is ready for cutting. Embedding materials : — (i) Usual form. White wax and olive-oil, equal parts. (ii) Paraffin-^ax and lard, of each three parts, paraffin oil one part. (iii) Cacao butter. Various modifications of these may be made : a hard mass jmust be used in summer, and a softer one in winter. Razors for hand-cutting must be broad-bladed and hollow- ground : the original " army razor " is the best. They must always be stropped in one direction. There is no advantage in special section cutters of various forms over ordinary razors. Directions for eutting by hand : — Be sure the razor is very sharp. Hold the razor firraly in the right hand with the fingers closed above the handle, take the wax mass between the index finger and thumb of the left hand, support the back of the razor on the former, and cut from left to right and from ~heel to tip of razor. Let the handle be kept in a line with the blade. Keep the blade well wetted with spirit, into which also the cut specimens must be floated ofE with a camel's hair brush after each sweep of the razor. (2) Cutting sections with microtomes is of most use when a large number of sections of the same tissue is required. The chief microtomes are : — INTRODUCTION. 9 (a) Banvier's. which consists of three hollow brass cylinders fitting one inside the other; to the most external a flat circular brass plate is fixed at one end, and to the other a cap which can be screwed on, carrying through its centre a fine screw. The tissue having been embedded in paraffin- wax in one of the cyhnders, the cap is adjusted, the micro- tome held in the hand an(i the screw turned until the wax is carried up sufficiently high for the embedded specimen to be cut ; the flat plate guides the razor. After each section is cut the screw is turned slightly, thereby presenting sufficient of the specimen for another section. (6) Stirling's is on the same principle, but is larger, and is fixed to a table by means of a screw. Only one cylinder, however, is fitted to the instrument. (c) Rutherford's provides a trough which may be used to contain a freezing mixture of ice and salt. When this is used the tissue is embedded in thicli gum, which, on freezing, becomes quite solid, and may be readily cut. Both (6) and (c) are generally provided with glass plates instead of brass, to guide the razor. (c^) Williams' is by far the best microtome for general use. It consists of a circular wooden box about eight or nine inches in diameter. Into the centre is fixed a circular solid brass cylinder, with a brass plate at the top. This box contains a freezing mixture, and is provided with a waste tube to get rid of the water as the ice melts. The cover of the box is wooden, but has a plate of glass fixed upon its upper surface ; it also has a central aperture to admit the top of the brass cylinder. This cover is fixed down after the freezing mixture has been placed in the box, and fastened vnth a lateral screw. The specimen, which should first be left for a couple of hours in water (to get rid of the spirit), is placed on the cylinder plate in a little gum. The gum is soon frozen, and the specimen is fixed by this means. The 10 METHODS. cutting is done by means of a razor, which is fixed in a movable triangular brass frame, supported on three screws. By the adjustment of these screws the thinness of the section is regulated. The frame works smoothly over the glass table. The upper surface of the razor should be slightly moistened with gum. As the sections are cut they should be swept off the razor with a camel's hair brush, and should be washed in warm water before staining. There are many other microtomes. The ice and salt in the case of freezing microtomes should be very finely pounded. (3.) Valentin's Jcnife is sometimes used to cut sections of fresh tissue. It consists of two blades, which can be separated by a screw. The section is cut between them. Teazing is done by taking a small piece of the tissue — e.g., tendon or heart- muscle — in a drop of the fluid in which it is intended to mount the specimen (generally glycerin or saline solution), on a slide, and tearing it in the direction of its fibres with a couple of strong needles mounted in handles to within one-quarter of an inch of their points. If it be stained, put a piece of white paper behind it; if transparent, use some coloured background. 3. STAINrCfG PlTODS. Almost all tissues require to be stained with some colouring material in order that their structure may be adequately demonstrated. The simplest and best is an aqueous solution of Jicematoxylin, which is prepared thus : — R Extract of hematoxylin . . 60 grms. Alum ..... 180 grms. Eub thoroughly together in a mortar, and add slowly 300 cc. of distilled water; then filter, and to the filtrate INTRODUCTION. 1 1 add 20 cc. of absolute alcohol. Preserve in a stoppered bottle. Alcoholic hcematoxylin is highly recommended by some authorities. Make saturated solutions of crystallized calcium chloride and of alum in proof spirit ; mix the solutions in the proportion of one to eight. To this mixture add a saturated solution of hsematoxylin in absolute alcohol, drop by drop, until the whole becomes a dark purple. This solution may be used at once, but is greatly improved by keeping. Carmine was formerly used much more than it is at present; it has the disadvantage of staining specimens a colour trying to the eye, whUst it has not the great selective power of hsematoxylin. Beale's solution is most frequently employed. It is thus prepared : — Dissolve carmine grm. i. in liq. ammonisB fort. 3 cc. warm, add aq. destiUat. 120 ec, and filter. Then add glycerini 30 cc, and spir. vini rectif. 120 cc, and keep in a weU-stoppered bottle. Oolding Bird's carmine is made by thoroughly mixing carmine grms. ij and borax grms. viij in a mortar, dis- solving in warm water for twenty-four hours. The super- natant fluid which should be decanted is then ready for use. The carmine staining must be fixed in the same way as the anilin {vide infra). Pierocarmin, or solution of picrocarminate of ammonia, is now much used, especially for " double staining " — i.e., when it is expedient to stain tissues with two colouring materials, in order to bring out certain special features in their struc- ture. It is prepared by adding a saturated ammoniacal solution of carmine to a saturated solution of picric acid until a precipitate forms, evaporating in a water bath to ^ its bulk — filtering and evaporating the filtrate to dryness : a crystallized mass, easily soluble in water, is obtained, which 12 METHODS. is picrocarmin. The strength of the solution should be about 1% to 3%. During preparation the ammonia should be kept in excess. Anilin staining fluids are sometimes used, of which the best are — Eosein — rose red. Purpurin. Anilin black. Anilin blue. "When used, the solution should be weak, and the colour should be fixed by passing the sections through water aci- dulated with acetic or hydrochloric acid (about 1%), and then transferring rapidly through the spirit and oil of cloves to the preserving medium. Eosin, a very pretty red dye, is used especially to stain nervous and vascular tissues : a "01 % solution in water is used. Specimens stained with this re-agent should be passed through acidulated water (as above) in order to fix their colour. Molybdate of ammonium is recommended as producing a cool blue-grey general stain, which does not interfere with the after use of carmine. A 5% solution in water should be used. The specimens are stained under the action of light in twenty-four hours. Nitrate of silver is used in aU cases when it is required to bring out the endothelial cells of serous membranes, as it is taken up by the intercellular substance and reduced as the black oxide under the action of the light, and so maps out the cells in dark lines. The fresh tissue should be plunged into a "o to '25% solution for about fifteen to twenty minutes. After the excess of the salt has been washed away in distilled water, the tissue should be exposed in weak glycerin to the action of sunlight until sufficiently dark. INTEODUCTION. 13 Chloride of gold is used to stain certain tissues, principally to show the nerves ; it is also used for cartilage — a -5 to -25% should be employed. For a classified list of staining fluids see Appendix. Directions for Stainimg. Use a weak solution of the dye, and allow the sections to remain in it for a long time. Examine the sections from time to time by transferring to a watch-glass containing spirit, in order to regulate the staining. Specimens which have been hardened in any preparation of chromium must be passed through a 1% solution of sodse bicarb, before staining with hsematoxyUn, in order to neu- tralise the effect of the chromium, after which the sections must be put into two solutions of hsematoxylin, the first weak, the second stronger. Preparing for mounting. — Specimens may be mounted at once in glycerin after cutting, staining, and washing in dis- tilled water ; but if it be desired to preserve in Canada balsam or Dammar the sections must pass, after staining, through — (a) Methylated spirit, )^ ^^^^^^ ^^^ ^^^^_ (6) Absolute alcohol, > (c) Qove oil, oil of tur- K^ ^^^^^^ ^^^^ transparent, pentme, or benzol, > They must remain in alcohol for five to ten minutes, and in clove oil for the same time. 4. MOUNTIB'G. For this process the operator must have — (1) Glass slides, which are slips of glass three inches long and one inch broad, about the thickness of ordinary window glass, with or without ground edges. (2) Oover glasses, which are made of extremely thin glass, circular or square, a to -f inch in diameter. 14 METHODS. (3) Section lifter, which is easily made by beatiag out flat one end of a thick copper wire, four or five inches in length. The flattened portion should afterwards be filed at the edges and rubbed smooth with sand-paper. (4) Mounting solutions. — These are: Glycerin, Canada balsam, and Dammar varnish. PreparatiSh of Canada balsam. — Mix equal parts of Canada balsam and choroform, and warm. The balsam is entirely dissolved. Filter. Preparation of Dammar varnish. — Dissolve gum dammar in powder 50 grms. in 150 cc. turpentine, and filter ; gum mastic 50 grms. in 200 ec. chloroform, and filter. Mix the solutions, and again filter. Directions for Mounting, In glycerin. — Sections may be mounted in glycerin direct from water, the cover glass being afterwards painted round with Canada balsam or dammar solution. In Canada balsam. — ^Having cut and stained the sections remove them by means of a needle, and pkce them one by one in a watch-glass or small dish of absolute alcohol. Leave them in this medium for ten minutes or more, and then pass them into clove oil in another watch-glass. Leave them untU perfectly transparent — i.e., for about five or ten minutes. Now take a clean glass slide, and on the centre place a small drop of Canada balsam mixture. Eemove the sections from the clove oil by means of the section lifter, and with a needle bring them down into the balsam. KnaUy, put another drop of balsam on the under surface of a cover glass, and allow it to fall gently upon the slide. The cover glass must not be pressed down. Aiter mounting, label the slides and set them flat in a tray box, made to hold a variable number of specimens from twelve to sixty. INTRODUCTION. 15 Microscopes. We append a list of some of the principal English makers, from any of whom a useful instrument may be obtained. Arnold, West Smithfield, E.G. Baker, Holbom, W.C. Beck, Cornhill, E.G. Grouch, Barbican, E.C. GoUins, Gt. Portland Street, W. Parkes, St. Mary's Eow, Birmingham. Pillischer, New Bond Street, W. Powell and Leland, Euston !Boad, N.W. Boss,, New Bond Street, W. Swift, University Street, W.C. Foreign Makers: — Hartnack's (1, Eue Bonaparte, Paris) microscopes are excellent, and the stand of No. VIII. in his catalogue, with oculars Nos. 2 and 3, and objectives (lenses) 4, 7, and 8, is recommended (cost about 250 frs.). The lenses of Garl Zeiss (Jena) are especially good ; A, D, and E are those in ordinary use (cost £1 7s., £2 8s., and £3 lis. respectively). Verick's microscopes (Paris, 2, Eue de la Parcheminerie, 2) are highly recommended. PAET I. PEACTICAL HISTOLOGY, Epitome of Appaeattjs necessary foe this wokk. Microscope. A pair of fine scissors. A pair of fine forceps. Two scalpels. Needles ntounted in handles. Bazor. Glass slides and cover glasses. Watch glasses (6). Section lifters (2). Labels. A box or cabinet for mounted specimens. Reagents — (the most used). Bichromate of potassium V/^ & 2°/„ solution. Bichromate of ammonium 5°/„ „ Miiller's fluid Chromic acid ■|°/o » Osmic acid, Auric chloride, and Silver nitrate. Methylated spirit. Absolute alcohol. Clove oil. Hsematoxylin solution, Picroearmin „ Carmine. Anilin colours. Eosiu. Sodse bicarb., 1°/;, solution. Acetic acid, „ Saline solution. Tannic and Boracic acids. Glacial acetic acid. Chloride of sodium. Glycerin. Dammar varnish, Canada balsam. Distilled water. 19 THE BLOOD. HUMAN BLOOD. Take a small drop of blood from the finger ; place it on a per- fectly clean glass slide, and put over it a glass cover. Examine witli magnifying power of 200 or 300. (Hartnack., Oc. 3, Obj. vii.) COLOTTEED COEPUSCLES : Circular discs ^-^ — -^^^ inch in diameter ; and Tuifn ™ch in thickness, depressed a little on each side. When seen side- ways, biconcave or dumb-bell shaped. Of a pale' buff colour, but when aggregated of a reddish tint. They have a tendency to run together, collecting in rolls ■ or rouleaux. Notice a cor- puscle as it rolls over, and observe the change in its form, being alternately circular and biconcave. The corpuscle has no nucleus ; the false appearance of a nucleus is occasioned by the refraction of light in passing through a biconcave disc. Prove this by slowly altering the focus. The corpuscles consist of two parts : a stroma, which is colourless, and the coloured part, a red crystallizable substance, hcsniogloiin. COLOTJELBSS COEPXTSCLBS ; Their proportion to the coloured varies from 2 to 10 in 1,000, the number being greater after taking food. When perfectly fresh, they are spherical and faintly granular ; they quickly alter and become markedly granular. About -^-^ inch in diameter ; nucleated, the nucleus not often apparent without the addition of weak acetic acid. They are nearly always isolated, and do not collect together or mix with the coloured discs. They are endowed with the power of spontaneous motion (amoeboid movement). This is best seen with a " warm stage." * Observe and draw the changes in form of a colourless corpuscle at intervals of five minutes. Action op Ebagents on the Blood : Take a small drop of blood on a slide and add to it a drop of saline solution. Cover it with a glass cover ; any reagent may now be made to act upon the blood by placing a drop of it on * See Appendix. 20 THE BLOOD. one side of tlie slip and applying a piece of filter paper to the opposite side. A stream of the fluid passes under the cover glass. This is called Irrigation. Irrigate specimens of blood with (1) Water : the red corpuscles become smooth and pale, and disappear. (2) Acetic acid : the same changes take place, the colourless corpuscles become more distinct and their nuclei more apparent. (3) Tamiio acid : the hsemoglobin collects in small lumps at the sides of the red corpuscles. (The action of carbonic acid gas, chloroform vapour, and certain other reagents, will be found in the Appendix.) H^MIN Ckystals : A drop of blood is dried on a glass slide ; two or three granules of common salt are added. With a capillary pipette add a drop of glacial acetic acid and then cover. Kaise the temperature gradually to the boiling point over a spirit lamp untU the greater part of the acid has evaporated. A number of smaU reddish-brown rhomboidal crystalline plates are seen. HAEMOGLOBIN CETSTALS : Take a drop of blood from a guineapig and let it coagulate on a slide ; add a little water and take up the clot with the forceps, and let several small drops fall upon another slide. As these evaporate, hEemoglobin crystals of various sizes shoot out from the edges, separately and in bundles. BLOOD-COEPDSCLES OF OTHEE VEETEBEATE ANIMALS. CoLOTJBED Corpuscles : In nearly aU MauunaUa the coloured corpuscles are round diso-Kke non-nucleated bodies, similar to those of man, but diflEering in size. In this respect they vary considerably. In Birds, Eeptiles, Amphibia, and Fishes, the corpuscles are oval and nucleated, the nucleus presenting a central elevation on each surface. These corpuscles are larger in birds than in mammalia; still larger in fishes ; and of a yet greater size in amphibia. GOLODBLBSS COKPUSCLES : The general characters of these corpuscles are similar in all animals, but they are found in much larger proportion in the blood of fishes and amphibia than in that of mammalia and birds. Irrigate a specimen of newt's blood with boracic acid 1°/^. The hsemoglobin collects around the nuclei of the red corpuscles. 21 EPITHELIUM. SQUAMOUS EPITHELIUM. (a) Feom the Mouth : With a blunt knife, or with the finger nail, scrape ofi >■■ thia shred from the mucous membrane of the cheek ; mix with a , drop of normal saline solution on a slide ; place on it a cover glass, and examine with a power of about 200 diameters. The ceUs consist of large, flat, roundish, or irregularly poly- hedral bodies, of yarious sizes. The .substance is more or less transparent, containing granular matter. The nuclei small, oval, frequently granular, and sometimes missing. (5) Feom the CEsophagus : Tease a, scraping from the oesophagus of a cat or dog in a small drop of glycerin. The oesophagus should be placed in potass. bichrom. 27„ for twenty-four hours, and then, after washing, should be left in hsematoxyliu solution for several hours. The nuclei of the cells are thus stained. GLANDULAE EPITHELIUM. Feom the Kidney oe Livee : Take a scraping from the freshly cut surface of a kidney or liver ; prepare in salt solution. The cells vary in shape and size, are pale, and fairly well defined, COLUMNAE EPITHELIUM. Feom the Intestine : Take a small portion of the intestine of some animal (eat, rabbit, or dog), place it in a 2°/„ solution of bichromate of potash for twenty-four hours or more; detach a fragment of the mucous surface by scraping lightly vsdth a knife, and tease up with needles in a drop of saline solution or glycerin on a glass slide. The cells are cylindrical or conical in form, with fairly well- defined outline ; protoplasm finely granular ; nucleus clear, oval, well-defined. When an aggregation of cells is seen from above, as on the surface of a villus, it has the appearance of a regular mosaic. 22 EPITHELIUM. Tbansitional : Best seen in tlie bladder, which may be prepared in the same way as the oesophagus. The shape of the cells should be noted: some are tailed, others concave OB one side, spindle-shaped, or caudate. The nuclei are very large. CILIATED EPITHELIUM. * Scrape lightly the mucous surface of a prepared trachea, and tease out in glycerin, and examine in a similar manner. The cells have oUia at one end and a tail at the other, with a large nucleus near the tailed end. Study of Ciliary Motion. With a sharp pair of scissors cut off a small fragment of one of the branchias of a living oyster or m'ussel. Put it upon a glass' slide in a drop of salt solution, and bring it under the microscope as quickly as possible (Hartnaok, Oc. 3, Obj. vii.). Ciliary movement at first very rapid ; soon becomes slower, and finally ceases.* Pigment : Can be studied in scrapings from the choroid, iris, etc. They are either branching dark irregular cells with clear nuclei, or flattened polygonal cells. * See Appendix. 23 ENDOTHELIUM. ENDOTHELIUM OF SEBOTJS MEMBRANES. Peepakation— 'The Silver Method. From an animal which has been recently killed by bleeding, take a portion of the omentum, pericardium, mesentery, or other serous membrane. Immerse it at once in a J°/o solution of nitrate of silver. Leave it for about ten minutes. Then wash thoroughly in water, and expose to the light for about a quarter to half an hour : that is, until it has assumed a brownish colour. Cut the membrane in small pieces with scissors, and mount in glycerin. ( Vide infra.) The endothelial linings of arteries and veins may be demon- strated in a similar manner. To show the endothelium of the lymphatic vessels, kill a rabbit rapidly by bleeding, open the thorax, lift up the lungs and heart, rub the tendon of .the diaphragm briskly with a camel's-hair brush wetted in saline solution. Pour upon the tendon the solution of nitrate of silver, and allow it to remain for ten minutes, then remove the tendon carefully, wash in distilled water, cut in pieces, expose to the light, and mount in glycerin with the brown surface uppermost. The Gltceein Peocess. The membrane is to be placed in a small glass dish partly filled, with distilled water. Take a clean glass slide, and im- merse it in the water. Then float the specimen on to the centre of the slide, taking care to prevent any folding of the tissue. Kemove the slide from the water, and arrange the specimen with needles. Take away the superfluous water with strips of filtering paper. Put a drop of strong glycerin on the under surface of a cover glass, and allow it to fall gently on the slide so as to form a thin layer between the glasses. Finally paint round the edge a layer of Dammai varnish. General Characters of Cells. On examination, the surface of the membrane is found to consist of a single layer of flattened polyhedral cells, variously modified, and forming a mosaic. Nuclei generally single, and only to be detected in deeply stained specimens, appear as bright and almost colourless oval bodies within the cells. When seen in profile, the nuclei occasion a projection from the surface. 25 THE CONNECTIVE TISSUES. VARIETIES. 1. White fibrous tissue. 2. Elastic tissue. 3. Areolax tissue. 4. Gelatinous or embryonal tissue. 6. Adipose tissue. 6. Cartilage. 7. Bone. I. WHITE FIBROUS TISSUE. ' Peepaeation. From a newly killed young rat or mouse the tail is out ofE close to the base. The skin is removed, and a small piece of the extremity is pinched ofE between the nails, and is drawn away from the rest of the tail. In separating this piece a number of fine threads, the tendons, will be noticed. One of these of moderate size is selected and teased out in glycerin. Steuctueb. The tissue is then seen to "consist of parallel iundUs of fibres, which vary in thickness, and are held together by an homoge- neous and albuminous cement substance. The individual fibres forming the bundles are straight or wavy, and are extremely delicate. Acetic acid added to tendons causes the fibres to smell •up and to disappear, owing to the presence in the tissue of a substance which is readily convertible into glutin or gelatin. The bundles of fibrils are surrounded by a more or less complete sheath of elastic tissue, which is not acted upon by dilute acids ; hence the constricted appearance seen in tendons to which acetic acid has been added. To demonstrate the presence of IKK TENDOlf coepusclbs. Pbepaeation. The most delicate of the tendons obtained from the tail of a rat is stretched, whilst it is still perfectly fresh, upon a glass slide. The extremities of the tendon are allowed to dry, and by this means it is maintained in an extended condition. A few drops of picrocarmin are placed upon the centre of the tendon, and are washed away with distilled water after the expiration of half an hour. A drop of glycerin acidified with acetic or formic acid is then added, a hair is placed by the side 26 THE CONNECTIVE TISSTTES. of the tendon to obTiate pressure, and a cover glass is put on, the preparation being sealed up in the usual way. Good results can also be obtained by mounting the isolated tendons in a 17„ solution of acetic acid to which J its volume of logwood alum solution has been added. The preparation must be examined as soon as possible (Schafer). Also by treatment with a 0-l°/„ solution of osmic acid for an hour, washing in distilled water for three hours, and subsequent staining with picroeaimin. Stedctuee. On examination the tendons thus treated are found to consist of parallel bundles of fibres, arranged in groups whose substance is almost colourless. Between each two groups is a lymph channel, in which lie nearly parallel layers of delicate stained cells — the conmecti/ee tissue or tendon cells — forming for each channel a single continuous row of rectangular plates. Each plate is provided with a more deeply staining nucleus. The cells are separated from each other by a cementing substance, and they possess fine processes. Each cell presents a straight ridge — the elastic stripe. This ridge is formed by the union of two or three concave portions of which the cell is composed, to enable it to adapt itself to the curved surfaces of the tendon bundles. The lymphatics may be demonstrated by staining the tail of a very young rat in chloride of gold, and then making fine transverse sections ; dark masses will then be seen in the tendon corresponding to the lymphatic channels filled with an albuminous fluid plasma. Badiating from these masses are fine septa — tlie cement substa/nce — binding together the contiguous bundles. 11. ELASTIC TISSUE. Pebpabation, Tease out a small piece of the ligamentum nuchas of an ox in glycerin and examine. STEtrCTUEB. Elastic fibres are thick and well defined; they do not form bundles ; they iranch dichotomously, and a/nastomose with each other to form a real network ; when torn they cv/rl up at the ends. They do not swell up when treated with acids, and they yield elastin. in. AREOLAE TISSUE. Pebpaeation. This form of tissue is best seen in specimens of intestine and skin. A small artificial buUa is formed in a rat or rabbit which THE CONNECTIVE TISSUES. 27 is still warm by the injection into the subcutaneous tissue of a 0'2°/j, solution of nitrate of silver or osmio acid, ■which is allowed to remain for ten to thirty minutes. The bulla is then opened with a pair of fine curved scissors, and the delicate subcutaneous tissue is rapidly removed and spread out on a glass slide. It is immediately covered with a thin glass, and the preparation is stained for twenty-four hours with picrocarmin. Glycerin is passed through until all the superfluous staining material is removed, after which the preparation is sealed up. Steuctcre. The tissue is composed of delicate bundles of ordimary mhite fibrous tissue, some of the fibres are fibriUated, and all interlace with each other ; the meshwork thus formed contains a few very fine fibrils of elastio tissue. The interspaces are filled with lymph-containing lymph oorpusclcs. Large plate-like cells which appear to lie upon the surface of the bundles of fibres are also seen. When viewed sideways these cells have a branched appearance, and form the plasmatic cells. Fat cells are also present. IV. GELATINOUS, EMBRYONAL, MUCOUS, OR WHARTON'S TISSUE. Peepabation. Present in the foetal umbilical cord, and in the foetal skin. The connective tissue is obtaiaed from a bulla formed by the injection of a dilute solution of gold chloride, in a stronger solution of which it is subsequently stained. Steuctueb. A transparent jelly-like substance in the youngest condition, containing a hyaUne mucous substance withm a reticular frame- work. At a later period hwidles of fifirous cormective tissue are apparent, as well as irmiohed cells, ilood-iiessels, and fat cells in an early stage of development. The tissue yields mucin on boil- ing. The vitreous humowr appears to be a variety of this tissue in which the branched cells have lost their processes. V. ADIPOSE TISSUE. Pbeparation. Tease out a small piece of fat in glycerin. Leave a small piece of fat, which has been partially teased, in ether for twenty- four hours, and the fatty portion will be dissolved out. Examine 28 THE CONNECTIVE TISSUES. tie preparation of areolar tissue formed by the injection of nitrate of silver. Steucttjee. Adipose tissue consists of a matrix or network of areolar tissue containing fat cells. Fat cells are clear, well defined, rounded vesicles of varying size, filled with an oily fluid, whicli often gives rise after death to erystalUne needles, probably of margarin, radiating, from the centre of the cell. In successful preparations a fine zone of protoplasm, with a mwleus at one pole, can be seen surrounding the cell more or less completely. The fat cells may either form compact masses, with only a small amount of connective tissue, or they may be more or less isolated. The tissue possesses a capillary network of blood-vessels. Between the fat cells flattened nuoleated connectwe-tissue cells may be demonstrated. 29 CARTILAGE. Cabtilage consists of two parts : 1. CeUs. 2. Matrix or Inter-oellulai material. According to the nature of the matrix, cartilage is classed as — 1. Hyaline cartilage. 2. Fibro-cartilage. 3. Elastic cartilage. I. HYALINE CARTILAGE. PREPARATIOlf. Hyaline cartilage consists of several kinds : costal, tracheal, articular (from the articular surface of bone), ossifying or inter- mediary, and embryonal. Portions of each of these cartilages should therefore be examined. The cartilages may be hardened in a solution of chromic acid 1 in 600, in a saturated solution of picric acid, or by the gold method. In every case the sections, which must be very thin, should be stained with carmine or hsematoxyUn. Steuctukb. All cartilage, with the exception of the free extremity of articular cartilage, possesses a delicate vascular connective-tissue sheath — tTw perioTumdrivm.- The cartilage oells are spherical or oval protoplasmic bodies, generally containing a single nucleus. The cell protoplasm forms a fibrillar meshwork which is con- tracted in embryonal and articular cartilages. Each cell is placed in a lacuna, enclosed by a firm, structureless but trans- parent matrix, yielding chondrin. In growing cartilage a special layer — tTie limiting membrane — can be distinguished between the lacuna and the ground substance. In some cases a single lacuna may contain more than one cell due to reproduction of the cartilage cell by fission : and the various stages in the division of cells may often be well seen. Near the perichondrium the cartUage cells become flattened and smaller ; near the articular surface they are branched : in ossifying cartilage they are arranged in parallel rows. The matrix possesses an anasto- mosing system of lacunse and canals ia connection with the lymphatic system. II. FIBEO-CARTILAGE. Preparation. As for hyaline cartilage. White fibro-cartilage occurs in the intervertebral substance and in sesamoid bones. 30 CARTILAGE. Stettctuee. It consists of groups of slightly flattened elastic cells, each ■with a round nucleus, and enclosed in a distinct capsule. The matrix is composed of bundles of fibrous tissue, which some- times form lameUse with occasionally a concentric arrangement. III. ELASTIC CARTILAGE. Prepabation : As for hyaline cartilage. This form of cartilage occurs in the lobe of the ear, in the epiglottis, in the cornicula laryngis, in the cartilages of Wris- berg and Santorini, and in the Eustachian tube. STBUCTtTEB. Elastic cartilage in the adult is hyaline cartilage permeated by elastic fibrils. TAe fibriU are arranged so as to form the trabe- culse of a reticular framework; they branch and anastomose very frequently. The meshes contain fusiform groups of large nucleated cells, surrounded by a larger or smaller amount of hyaiine cartilage substance. 31 BONE. Preparation. The fresh bones of any small animal, well cleared of the surrounding tissues, are to be placed for two or three weeks in a large quantity of 5°/o solution of chromic acid, containing five drops of hydrochloric or nitric acid to each ounce of the solution. When the whole of the earthy matter is dissolved out, sections are to be out with a razor in various directions and examined in glycerin. General Characters. In transverse sections of the compact tissue of long bones are seen Haversian systems, more or less perfect, and Haversian interspaces. Each system consists of the central Haversian canal, which is generally round or oval, with an average diameter of ^^ in., and is lined with a delicate membrane continuous with the periosteum, surrounded by concentric lamellae of bone, in which are the lacunse and canalicuh. Laevmm ^^nr in. in length, generally well marked, contain shrunken bone cor- puscles. CamaliouU usnally indistinct, but when seen plainly forming a complete system of communication between the lacunse of the same and neighbouring Haversian systems and interspaces. They contain in the fresh condition prolongations from the bone corpuscles. Each Haversian system is more or less isolated from its neighbour by a layer of bone which con- tains but few canaliculi. The Haversia/n interspaees are the portions of bone filling up the interval between one or more of the circular Haversian systems. They do not contain any cen- tral canal ; their general characters are otherwise similar to the systems. In longitudinal sections the Haversian canals which run longitudinally are seen to anastomose freely by transverse or oblique channels. The lacunas and canaliculi present ' much the same characters as in transverse sections. The Haversian canals which run near the circumference of the bone may open on the outer surface so as to admit blood-vessels from the peri- osteum, whilst those opening into the meduUary canal receive blood-vessels, and in the case of the larger ones medulla from the interior of the bone. In preparations of calcified bone it may be seen that the • lameUse are bolted together by the perforating fibres of Sharpey. 32 BONE. Bone situated immediately beneath an articular cartilage differs in not possessing Haversian canals, in the lacunae being three or four times larger than in ordinary bone, and in being desti- tute of canalicuh. The periostewn covering the free surface of bones consists of an external layer of dense fibrous tissue supplied by capillary blood-vessels, and an internal osteo-genetic layer containing a plexus of delicate connective-tissue fibrils ; in the meshwork formed by these fibrils are capillary blood-vessels and a number of nucleated cells. The medulla is of the yellow kind, and is chiefly composed of fat cells, with intervening membranes of flattened connective-tissue cells ; it also contains numerous cells possessing one or two nuclei. In spongy bones — e.g. a vertebral, carpal, or" tarsal bone— the tissue consists of bone-trabeculse, forming a more or less open framework, in which is embedded the medullary substance. Bone- trabeoulse contain lacunae with bone-corpuscles and ill developed canaliouli. The medullary substance is of the red kind; it is rich in blood-vessels, and in cells having the characters of lymph- corpuscles, fat-cells, &;c. THE DEVELOPMENT OF BONE. . (a) In Cabtilagb. (J) In Membrane. (a) Bone developed in cartilage or endochondral bone. Stage i. Hyaline cwrtUage covered by perichondrium. The periohondrium consists of an outer layer of embryonal connective tissue, and an inner osteo-genetic layer containing spherical cells — ^the future osteoblasts, and blood-vessels. Stage ii. The inner layer of periohondrivm, penetrates the cartilage, forming for itself chan- nels by a,bsorption, and carrying with it blood-vessels and cells. The growth of the perichondrium inwards starts at the centres of ossification. Stage iii. The jjrimary marrow cavities are formed by the appearance of lacunse near the cartilage channels, which then become confiuent ; whilst the trabeculae separating neigh- bouring lacunse become calcified. The primary marrow filling the marrow cavities is the periosteal ingrowth containing the vessels and cells. Stage iv. The calcified trabecule after becoming ensheathed with osseous material, are absorbed. A network of osseous trabeculae instead of a network of calcified cartilage is thus formed, whilst the whole tissue resembles spongy bone. The surfaces of the osseous trabeculae are covered BONE. 33 with osteoblasts, wMlst the cavities separated by the tiabeculse are filled with marruw rich in vessels and cells. Stage v. The endochondral spongy bone is absorbed, from the centre outwards ; the large medullary cavity is thus formed. .Bone from the peri- osteum is also developed round the endochondral bone. The osteo- Masts multiply and become converted into the osseous matrix and into bone-corpuscles. The meshes of the spongy periosteal bone are the Haversian spaces; they contain marrow from which a series of concentric lamellse are formed. The spaces are thus gradually reduced to Haversian canals. Stage vi. All the endochondral bone is absorbed, and the ossified trabeculae are represented by the interstitial substance separating the concentric Haversian lamellse. * (J) Intramembranous. The membrane corresponds to the future periosteum ; it consists of two parts as above. Stage i. The cells of the osteo-genetio layer — ther osteoblasts— increase and form the osseous matrix by excreting ossein around them and the bone-corpuscles, thus forming ossified trabeculse which start from the centres of ossification. Stage ii. Portions of the trabeculse are absorbed (osteoporosis), whilst, as in endochondral bone, concentric lamellas are formed by the marrow in the Haversian canals. The formation of intramembranous bone is identical with the formation of periosteal bone. The absorption of osseous sub- stance is in nearly every case associated with the presence oi multinucleated giant cells — the osteoclasts. 35 MUSCULAE TISSUE. VARIETIES. 1. Striated or striped. 2. Plain or unstriped. I'EBPAKATION. For the examination of fresh muscle, tear away a small frag- ment of the tissue with a pair of forceps from a recently -killed cockroach or water-beetle (_Ih/iis(»is margmalis), and at once tease it up thoroughly in a drop of salt solution or water on a glass slide. Examine as soon as possible. Muscle is also prepared by taking small pieces of fresh tissue from the voluntary muscles and the heart, as well as from any of the viscera containing unstriped fibres, and soaking them for a few weeks in a 2°/^ solution of chromic acid, or in a ^°/„ dsmie acid for one hour, then wash in distilled water for two hours. A fragment of the tissue is removed, and, having been well teased with needles, is examined in water, glycerin, or other medium. Unstriped tissue is prepared by distending a piece of rabbit's intestine with saline solution, leaving it in a I'/o solution of anilin black for twenty -four hours, and stripping ofiE the outer coat with forceps. Small pieces of this coat are then to be mounted in glycerin. GENERAL CHARACTERS. Steiped Muscular Tissue. From Vohmtwry Muscle. — Consists of long fibre's, which are cyUudrioal, but appear in transverse section as rounded polygons. ]Sach fibre is made up of a number of exceedingly fine and deli- cate filaments, the fibrilke, enclosed within the sarcolemma. The fibres are aggregated into bundles; several bundles form- ing faseieuli, and these the anatomical musole. Perimysium or fibrous connective tissue surrounds the bundles; from it pass off small processes of connective tissue, with cell plates and plasma cells, between the muscle fibres — tTis endomysium. Each fibre consists of broad dim bands of highly refractive substance representing the contractile portion of the muscle fibre — the contractile discs — alternating with narrow bright bands of a less refractive substance — the interstitial discs. After hardening, each contractile disc becomes longitudinally striated, the thin oblong rods thus formed being the sarcous elements of Bowman. The sarcous elements are not the optical units, since each consists of minute doubly refracting elements — 36 MUSCULAR TISSUE. tlie disdiaclasts of Briicke. When seen in transverse section the contractile discs appear to be subdivided by clear lines into polygonal areas — Cohmhewis fields, each coiTesponding to one sarcoTis element prism. The clear lines are due to a transparent interstitial fluid substance pressed out of the sarcous elements when they coagulate. The sarcoleinma is a transparent struc- tureless elastic sheath of great resistance which surrounds each fibre. From the sarcolemma transverse membranous septa — the membrltnes of Xrame— extend inwards across the muscle at regular intervals. By these septa the muscle fibre is divided into equal-sized muscle com/pa/rtments, each containing one contractile disc. The membranes of Kiause are so placed that each passes across the middle of an interstitial disc, which is thus divided into two lateral discs, A thin transverse median disc — the disc of Hensen — is occasionally seen to divide the contractile disc. In some fibres, chiefly those from insects, each lateral disc contains ii row of bright granules forming the granulwr layer of Flogel. The fibres contain nuclei, which are roundish, ovoid, or spindle-shaped in different animals. These nuclei are situated close to the sarcolemma, their long axes being parallel to the fibres which contain them. Each nucleus is composed of a uniform network of fibrils, and is embedded in a thin more or less branched film of protoplasm. The nucleus and protoplasm together form the muscle cell or mvscle corpuscle of Max Sohultze. Miiscular Tissue of the Heart. — Fibres very small and finely striated. Strisa generally indistinct, often showing only as coarse granules. There is no sarcolemma. Many of the fibres anastomose and branch. Non-Stkiped Musculae Tissue. Made up of bundles of cells, bound together by an albuminous cementing substance — the endomysimn — in which lie connective- tissue cells and a few fibres. The peri/im/sivm continuous with the endomysiimi is the fibrous connective tissue surrounding and separating the bundles of muscle cells. Fibres fusiform, band-like, or spindle-shaped, containing elongated or staff- shaped nuclei, placed midway in the fibres. Each muscle cell consists of a fine sheath, probably elastic ; of a central bundle of fibrils representing the contractUe substance ; and of an oblong nucleus, which includes within a membrane a fine network anastomosing at the poles of the nucleus with the contractile fibrils. Ends of fibres usually single, sometimes divided. There is no sarcolemma. NERVE TISSUE. VARIETIES. , T,T jj, ( Medullated. 1. Nerve fibres | Non-mednllated. 2. Nerve cells. Pebpaeation. Cut longitudinal sections of a portion of a sciatic nerve, which has been hardened for about ten days in a 2°/o solution of bichromate of potassium, or a mixture of spirit and J°/„ chromic acid in equal parts. Stain these deeply in hematoxylin solution, and tease them out, then mount in the ordinary way \rt Canada balsam. Cut also transverse sections, stain, prepare and mount in similar manner. GENEEAL CHAEACTEES. 1 . Nbevb Fibebs. (as) Medullated Nerve Fibre. Feom Spinal Nbevbs. — The nerve trunks are composed of a variable number of bundles (fimiouW) of nerve fibres which have a special sheath {perineuriv/m or nev/rilemmd) and are en- closed in a firm fibrous sheath (epmewriwni), which also sends in processes of connective tissiue, connecting the bundles together. In the funiculi between the fibres is a delicate supporting tissue (the endonewrivm). Each nerve fibre is made up of the following parts : — (1) PrimAtvee nerve slieath, or tmcleated theath of Schwann. (2) Medullary slieath, or mhite substance of Schimam/n. (3) Amis cylinder, primitive band, axis band, or axial fibre. Sehreann's sheath, which is the external layer of the fibre, appears to be a simple, transparent, colourless, homogeneous structure, with a varied number of oval nuclei attached. It pro- bably consists however of nucleated endothelial cells joined end to end and forming a complete membrane. The medullary sheath, the middle layer, which forms the greater part of the nerve, surrounds the axis cylinder, and has a double contour ; and at regular intervals are constrictions in the medul- lary sheath (Ranvier's constrictions), caused by the thinning or interruption of the medullary substance. 38 NERVE TISSUE. The axis cylinder is situated ib the middle, and appears as a faintly marked band, with an exceedingly fine and even outline, and is made up in the prepared specimen of a number of most delicate fibrils {primitive fiirils). From Cbbbbbo-spinal Cbntee, the Optic and Auditoey Neevbs. — The general appearances are the same, excepting that there is no sheath of Schwann. (J) Kon-meduUated Nerve Fibre. Feom Sympathetic and Olfactory Neevbs. — Consist of simple filaments forming an axis cylinder, and surrounded by a nucleated sheath of Schwann. 2. Nerve Cells. (Are examined with the brain and spinal cord.) 39 NERVE TISSUE.— Paper II. Spinal Cord. Preparation, — Small lengths (about J to | inch) of the spinal cord of the cervical, dorsal, and lumbar regions of a calf, sheep, or pig, should be hardened in 5°j^ solution of bichromate of ammonium for a week, and should then be transferred to spirit — or the usual mixture of chromic acid and spirit may be used. A solution of eosin is recommended by some for staining the sections, but carmine or picrocarmin and hsematoxylin act equally well. AniUn black l°/o solution stains the ganglion cells excellently. Structure consists of (1) white, and (2) grey matter, supported by fine connective tissue (neuroglia). . '" - (1) White, situated externally and forming the greater por- tion of the cord, is most marked in the dorsal region, and tl^en in the cervical ; it is made up of longitudinal fibres from ^■^'— 1 5008 inch, which are finer in the posterior and postero-lateral columns than elsewhere, of some transverse fibres in the anterior white commissure, and of a few nerve cells. (2) Cfrey, forms the interior of the cord, and on transverse section presents two crescentic masses with concavities outwards, joined across the middle by a transverse piece (posterior gre^ commissure). In the centre is a small canal lined with column^i ciliated epithelium. — The crescents present {a) anterior horn (cornu), short and thick, extending towards the attachment of the anterior roots ; (J) posterior horn, longer and more slender. In the concavity of each crescent the grey matter sends out pro- cesses which enclose portions of the white substance. The grey matter is made up of small, non-medullated fibres which chiefly form a dense network, continuous with the roots of the nerves ; part of these fibres are derived from the branches of the nerve-cells, which are embedded in the network. These cells are of two kinds : — (1) Large, hranehed, and nucleated, which are chiefly to be found in the anterior cornua, especially at their upper and outer parts, but also at the inner part of the base (cervix coma) of the posterior horn, forming the posterior vesicular column, which is best marked in the lumbar enlargement of the cord ; and, lastly, in the concavity of the crescent is a group of cells, occupying a projection of grey matter there (tractus intermedio-lateralis), which exists chiefly in 40 NEKVE TISSUE. the dorsal region. (2) Smaller cells scattered throaghout the grey matter, but chiefly at the tip (caput cornu) ot the posterior cornu, in a finely granular basis, and among the posterior root fibres (substantia gelatinosa eimerea of Rolando). Origin op the Spinal Nbbves. (a) Anterior roots, pass into the anterior cornua, and are there distributed thus : — (1) Some fibres pass backwards, and form connections with fibres from elsewhere ; (2) Some spread obliquely upwards and downwards ; (3) Some pass externally to the lateral columns ; and (4) Others internally cross to the other side in the anterior white commissure. (J) Posterior roots, enter the posterior cornua, either at the tip, through the substantia gelatinosa, or by the inner side. Those which enter at the tip, as a rule, turn upwards or down- wards : some reaching the anterior cornua ; and the others, the opposite side, through the posterior grey commissure. Of those which enter by the inner side of the cornua — (1) Some pass at once into the grey matter ; (2) Others through the posterior vesicular columns ; (3) The majority pass up (or down) in the white substance of the posterior columns, and enter the grey matter at various heights ; (4) Not a few are lost in the pos- terior white columns. 41 NERVE TISSUE.— Paper III. Cebebbum. I¥eparation. — Place small pieces from different parts of the cerebrum in a 2% solution of bichromate of ammonia for two days, after which transfer to weak, and finally to strong spirit. Care must be taken to get vertical sections. Stain in anilin blue-black. Struetiire. — The cerebral convolutions are divisible into (a) Cortical grey portion, and (J) White meduUary substance. (a) Cortical grey portion is composed of — (1) An external layer containing a few small cells with fine processes embedded in a considerable quantity of neuroglia. This layer composes about •^ of the whole thickness of the grey substance. (2) TJie second layer of small, densely aggregated, pyramidal cells, provided with branching processes. This layer is of nearly the same extent as the previous one. (3) T/ie third layer is of greater width, and is somewhat paler than the first and second layers ; it is composed of large and small pyramidal cells, arranged with their apices turned towards the surface of the convolution. The larger cells average ^^ in. across their base. The cells are arranged in groups, and are separated from each other by bundles of radiating nerve fibres, each bundle being about y^iy in. in diameter. The pyramidal cells send downwards three processes, of which the middle one forms an axis cylinder. Both cells and processes are striated longitudinally, and generally contain a little yellowish pigment. (4) The fourth layer is some- what narrower than the preceding ; it consists of small, irregu- larly-placed, granule-like corpuscles, with delicate processes. The cells are less distinctly separated into groups. (5) The lamest layer is of considerable width ; it contains, in addition to cells resembling those of the fourth layer, fusiform cells arranged vertically at the summit of a gyrus, but parallel to the surface of a sulcus. This layer gradually blends with (J) The white gubstamce, composed essentially of White nerve fibres, which are smaller than those of the spinal cord, with an average diameter of -nmnr in- In the neighbourhood of the cortex, a few non-medullated fibres can be seen, (c) T/ie nevroglia, formed- of a, homogeneous matrix, in which lie numerous elastic fibrils, connected into a network. With this network, the branched nucleated cells — of Deiter — are con- nected. 42 NERVE TISSUE. Cebebellum. Preparatym. — ^As for cerebrum. Stain in anilin blue. Struotwe. — Like the brain, it Is divisible into (a) Cortical grey; and (J) Internal white substance. The Cortex is divisible into — (1) The Molecula/r layer, the most external, consisting of a nerve network containing small pear-shaped multipolar ganglion cells. The fibres of the network in the more superficial portions are nearly vertical to the surface ; they are derived partly from the neuroglia, partly from the processes of the cells of Purkinje. (2) A single layer of large spindle-shaped ganglion cells -j} „ — TiiVir in- ™ diameter, Pv/rhm^e's cells. Each cell possesses one branched process which extends into the molecular layer, where it branches dichotomously, some of the finest ramifications loop- ing backwards to terminate in the granular layer, and an un- branohed axis cylinder process passing downwards. The cells lie in a pericellular space, and each consists of a minute network of fibrils extending into the branched processes. The nucleus is spherical and oval. (3) The gra/imla/r layer, containing a network of minute fibrils, and dense groups of granule-like corpuscles. These corpuscles aterage tsW — ^Att ii- in diameter. (*) The medullary centre or internal mhite substance consists of nerve fibres arranged in parallel or interlacing bundles. The newogUa of the white matter contains rows of small cells, each with a spherical nucleus, between bundles of nerve fibres. The blood-vessels of the grey matter pass from the pia mater in a vertical or oblique direction, and anastomose into a uniform network. The blood-vessels of the white matter form a network with longitudinal meshes. The vessels lie in lymph channels, the peri/Boscula/r lymphatics of His. 43 BLOOD-VESSELS. Varieties. Of thiee kinds. (A) Arteries, (B) Veins, and (C) Capillaries- (A) ARTERIES. Peeparation. Longitudmal and transverse sections of a medium-sized artery (or vein), wMoh has been hardened in a \°j^ solution of potassium bichromate, should be stained in logwood, prepared, and mounted in Canada balsam. Structube. Arteries (except those of minute size) have three coats : — 1. Internal coat, consisting of (a) An epithelial layer, forming the lining of the vessel, of thin elliptical or irregularly polygonal cells, often lanceolate, with nuclei and nucleoli ; (6) A subepithe- lial layer of delicate connective tissue, with branched corpuscles; (o) Elastio layers of longitudinal elastic networks and " fene- strated " membrane. 2. Middle coat chiefly consists of circular unstriped nmsole fibres, mixed with elastic fibres, and a sparse amount of connective tissue. 3. External coat (tunica adventitia) chiefly consists of fine and closely-felted bundles of covmective tissue, together with longitudinal elastic tissue between them. Note. — In the largest arteries, the middle coat consists of alternate layers of elastic tissue and unstriped muscle. (B) VEINS. Pbepakation. As of the arteries. Structure. As of the arteries, with these differences : — The elastic tissue of the internal coat seldom occurs in the form of fenestrated membranes. The middle coat is thinner, contains less mtiscular tissue and more white connective tissue. The external coat of some veins has a considerable amount of unstriped muscular fibres. (C) CAPILLARIES. Peeparation. Best obtained from the pia mater. The brain of some animal, such as a cat or dog, should be left for two days in a 2°/;, solution of potassium bichromate, then the pia mater may be stripped off 44 BLOOD-VESSELS. in pieces, stained, and mounted in the usual manner. Capillaries are well seen also in the mesentery of a oat or other animal. Steuctubb. The walls of the capillaries proper are formed entirely of a simple epithelial layer of flattened lanceolate cells, joined edge to edge, and continuous with the layer which lines the arteries and veins. The larger capillaries have an outside structureless or finely fibrillated coat. In vessels rather larger (small arteries and veins) there is added, outside the epithelium, a thin layer of unstriped muscular fibre, 45 ALIMENTARY CANAL AND GLANDS CON- NECTED WITH IT.— Paper I. (A) TONGUE. PKEPARA.TION, Vertical sections of the tongue of rabbit or cat which has been hardened in equal parts of 5°/^ chromic acid and spirit should be stained and treated in the ua.ual manner. Sections of the papUla foliata which is found on either side of the base of the rabbit's tongue should also be treated in a similar manner. Sthuctuee. Consists of three coats : — 1. The m%u}ous coat is covered with stratified epithelium, and is provided with papillae (of three kinds in the human subject — viz. circumvallate, fungiform, and fiUform), and these again with small, closely set secondary papiUse, which are hidden under the epithelium. The secondary papillae are found every- where in the mucous membrane, and not over the larger papillae alone ; but these latter are confined to special parts, and, as a rale, are placed in cii-cular depressions. Surrounding some of the papillffi, notably the circumvallate, are certain ovoidal or flask-like bodies, the so-called ' taste-buds,' composed of modified epithelium. Nerves are supposed to terminate in these cells. In the mucous membrane also are small tubular glands, some secreting mucus, but others whose ducts open into the trenches around the taste organs, secreting a more watery fluid. Lymph- oid tissue, which here and there forms distinct folHoular glands, is found in large quantity in the mucous membrane at the pos- terior part. Crypts or recesses, too, are found, the walls of which are studded with nodules of lymphoid tissue. 2. The submueous coat is incomplete and scanty. 3. The muscular coat consists of longitudinal, transverse and vertical bundles of striated muscle. (B) SALIVARY GLANDS are three on each side (parotid, submaxillary, and sublingual'", which agree in structure, but differ in size and position. Pbepabation. Sections of submaxillary gland of a oat or dog and of the parotid of a rabbit or dog should be made in various directions after hardening in chromic acid and spirit. Cajisiile of flbrous tissue, which sends septa into the substance 46 ALIMENTARY CANAL. of the gland, supporting blood-vessels, lymphatics, nerves and ganglia. Stetjctuke : As of oompoand tubular glands, in which a lobule is made up of convolutions of a main division of a duct bound together with connective tissue. The convoluted parts are lined by and almost filled with a. single layer of columnar cells (salivary cells) enclosing a nucleus. The granular appearance which is frequently seen in the salivary cells is due to the very dense net- work ai fibrils which they contain. These cells, when isolated, are not unfrequeutly found to be branched. The basement membrane of the tubes consists of branched and flattened cells, and between it and the salivary cells are found, here and there, (not in the parotid) granular semilunar bodies, the semilimes of Heidenluim. Mucous cells or goblet cells are also found in the lumen of the tubes in the mucus secreting glands. The smallest divisions of the ducts have a relatively small lumen, and are lined near the convolutions with flattened epithelium, and then with nucleated columnar cells which present a longitudinal striation. The larger ducts acquire an outside coating of connective tissue, and are lined with a single layer of columnar epithelium, con- taining an intracellular network of fibres arranged longitudinally. In the walls of the largest duct are unstriped muscular fibres. Note. — The salivary glands have also been described as of the compound racemose type. 47 ALIMENTARY CANAL AND GLANDS CON- NECTED WITH IT.— Paper II. (C) TONSILS. Preparation. Sections made from a tonsil which has remained for a week in ^°/o solution of chromic acid, and subsequently in spirit, should he stained with logwood, and mounted in Canada balsam. An enlarged tonsil which has been removed from a child will answer the purpose. STRtrcTTJRB. A tonsil consists of an elevation of the mucous membrane presenting upon its surface fifteen orifices leading into crypts or recesses, in the walls of which are placed nodules of lymphoid tissue. These nodules are enveloped in a less dense lymphoid or adenoid tissue which reaches to the mucous surface. The mucous surface is usually covered with squamous epithelium, and may present rudimentary papUlse which are then formed of adenoid tissue. The tonsil is bounded by a fibrous capsule. Into the crypts open a number of ducts of mucous glands. (D) (ESOPHAGUS. Pbbpaeation. Small pieces of the oesophagus of a dog both of upper and lower parts should be hardened in chromic acid and spirit. The mucous glands are best seen in sections from the lower part of oesophagus. Structtjrb. Of three coats : — 1. An eaiternal or muKyidar coat consists of two layers, longi- tudinal and circular, the former or external layer at the com- mencement being disposed in 'three fasciculi, one in front and one on each side. At the upper end of the oesophagus, the mus- cular coat is red, and consists of striated muscle ; lower down it becomes paler, and the fibres are mostly unstriated. 2. A giibmwKms coat consists of areolar tissue, and contains mucous glands (tubular) whose ducts pass through to open on the mucous membrane. 3. A nmcous coat which is firm and wrinkled, pro- vided with minute papillae, and covered with thick stratified scaly epithelium. It is separated from the submucous coat by a layer of unstriated longitudinal muscular fibres, which is par- tially imperfect as a layer above but complete below (muaoularis mmooiai). 49 ALIMENTARY CANAL AND GLANDS CON- NECTED WITH IT.— Paper III. Pbepaeation. Sections of liardened pieces of stomach, duodenum, ileum, and colon, made in various directions, should be stained in logwood ; some of those of the stomach should be placed in Vj^ solution of anilin blue and left in it for half an hour, so as to stain thoroughly. After staining, prepare, and mount as usual. (E) STOMACH. Structtjeb. Of four coats : — 1. Mitcoug or internal coat, is smooth, soft and pulpy, pink, becoming gray soon after death. Thickest at pylorus, thinnest at the great curve. Loosely connected with the muscular coat by means of the submucous, and so presenting temporary ridges (rugse) when the organ is contracted. It consists almost entirely of small tubular glands, arranged close to and parallel with each, other, varying in diameter from yjirth to shfi^ °^ ^.n inch, and in length from ^th to ^^^jth of an inch, lined to a variable extent by columnar epithelium, which also covers the whole of the mucous membrane. The tubular glands are for the most part simple, except near the pylorus, where they become larger, longer, and branched. The glands consist of a basement mem- brane formed of branched stellate cells joined edge to edge, and sending processes on the one hand, to join the retiform tissue of the mucous membrane, and on the other to support the gland cells. The glands are of two kinds, differing chiefly in the character of the cells and their secretion. The one, or so-called " Trmomis glands," often branched, confined to the pylorus, are lined throughout by columnar epithelium, although towards the " fundus " or closed extremity of the gland, it tends to become cubical. The other, or "peptie glands," distributed throughout the stomach, except at pylorus, but best marked perhaps towards the cardia, less often branched, are lined to a variable extent by columnar epithelium, which is succeeded at the neck of the gland by large, coarsely granular cells (" peptic cells ") ; at the fundus these peptic cells do not form a regular lining to the gland, but occur here and there, producing bulgings of the basement mem- brane, the rest of the tube, except a small central channel (lumen) is filled with finely granular, polyhedral or angular cells (" central cells "), which are said to be continuous above with the colum- nar cells of the neck, and which also resemble the cubical cells lining the fundus of a mucous gland. Between and beneath the 4 50 ALIMENTAKT CANAL. glands is a quantity of delicate connective tissue, together with a small amount of retiform or lymphoid tissue, which here and there is collected into small masses somewhat resembling the solitary follicles of the intestine. A double layer (circular and longitudinal) of unstriated muscle (muscularis mucosae) separates the mucous membrane from the submucous coat. 2. The sub- muoous coat consists of areolar tissue with some fat, together with blood-vessels and lymphatics ; small nerve ganglia and fibres are also found in it. 3. The muscular coat consists of three layers of unstriated fibres, externally of longitudinal, then of circular, and internally of oblique fibres ; . the circular layer is the only com- plete one. Between the layers may be found plexuses of nerves. 4. The serous coat is the peritoneal covering of the organ. Note. — It may be as well to mention that the so-called "peptic cells" are no longer thought to secrete the pepsin. 51 ALIMENTARY CANAL AND GLANDS CON- NECTED WITH IT.— Paper IV. (F) SMALL INTESTINE. Steuctcteb. As of the stomach, with the foUowiug difierences : — 1. Mucous coat possesses (a) valrmlce conrnventes, which are per- manent folds or crescentic projections running transversely to the axis of the intestine, and containing the submucous coat. They first appear in duodenum, not far from the pylorus ; are' largest in duodenum and upper half of the jejunum, and then gradually become smaller imtil they disappear about the middle of the Ueum. (J) Villi are small processes, closely set on every part of the small intestine, over the valvulss conniventes as well as between them. They are conical and flattened in form, sometimes cylin- drical or with the free end clubbed. Largest in duodenum and jejunum, in length varying from one-ftrurth to one-third of a line ; smaller, shorter and fewer in Ueum. They consist of pro- jections of the mucous membrane, being covered with columnar epithelium, enclosing blood-vessels, lymphatics and muscularis mucosa, bound together by fine retiform tissue, which also forms the basement membrane, (c) Crypts of lAsberhiikn are very numerous, small tubular glands existing everywhere in the smaller intestine; they are lined with columnar epithelium. ((?) Srvnner's glands are small compound tubular glands found in the duodenum, lying in the submucous coat, the duets of which pass through the mucous coat (e) Peyer's giands, or lymphatic follicular glands, which occur either solitary or collected (' agmi- nated') into oblong patches. When solitary, they are found everywhere in the small intestine, both between and upon the valvulse conniventes ; when agminated, they occur in the Ueum, especially at its lower part, in its long axis opposite the attach- ment of the mesentery. 2. The Timsoular eoat has no oblique fibres. 3. The serous coat of the duodenum is partially incomplete. (G) LARGE INTESTINE. Steuctueb. As of the small intestine, with the foUowing differences : 1. Mucous coat has neither true vUli nor valvulse conniventes, and its crypts of Lieberkiihn are longer, more numerous, and are placed more closely together. The lymphoid foUioles are always solitary. 2. Muscular coat — in the colon and caecum the longitudinal layer is collected into three flat bands. 3. Serous coat, of the colon and upper part of rectum is deve- loped into small projections containing fat (appendices epiploicse). It is incomplete in some parts. 53 ALIMENTARY CANAL AND GLANDS CON- NECTED WITH IT.— Papee V. (H) PANCREAS. Peeparation. As of the salivary glands. Steucttjke. The capsule and septa as well as the blood-vessels and lym- phatics are arranged as in the salivary glands. It does not, however, contain the semilunar granular bodies (" semilunes of Heidenhain "), and it is looser and softer, the lobes and lobules being less compactly arranged. The larger duets possess a very distinct lumen, and amembrana propria lined with columnar epithelium cells which are longitu- dinally striated, but are shorter than those found in the ducts of the salivary glands. In the smaller duets the epithelium is short and the lumen is smaller. The intermedia/ry d/ucts o^mag into the alveoli possess a distinct lumen, with a membrana propria lined with a single layer of flattened elongated cells. The alveoli are branched and convoluted tubes, with a membrana propria and a single layer of columnar cells. The cells consist of an outer part nearest the membrana propria which is homogeneous and stains the more deeply ; and an inner, more granular, and less readily stained portion. The alveoli have no distinct lumen, its place being ts^en by fusiform or branched cells. (I) LIVBE. Preparation. Small portions of the fresh liver of a pig, rabbit, or puppy, should be steeped for four or five days in a 2°/^ solution of potassium bichromate, and then for one or two days in methy- lated spirit. Sections should then be cut and treated as usual. It is as well also to mount sections of liver which has been injected through the portal vein with 2°/;, solution of Berlin blue, and then hardened in spirit. Stkuctube. It has a serous and fibrous coat. The former is absent from the posterior border and from the portal fissure, where the latter, which elsewhere is thin, is most developed. A strong sheath of areolar tissue (" Glisson's capsule ") surrounds the vessels of the organ as they ramify in it, and, at the transverse fissure, becomes continuous with its fibrous coat. The Iwer-substance proper consists of lobules, which are closely packed polyhedral 54 ALIMENTARY CANAL. masses more or less distinct, arranged round the sides of the branches (sublobular) of the hepatic veins and oonnected to them by minute veins which begin in the centre of the lobules (intra- lobular veins). Each lobule consists of a mass of compressed spheroidal or polyhedral nucleated and nucleolated cells from xT?5^th to ^ifth of an inch in diameter, often containing oil glo- bules. Surrounding the lobules is a variable amount of fine connective tissue in which is contained a minute branch (intra- lobular) of the portal vein, a branch of the hepatic artery and of the hepatic duct, together with minute lymphatic vessels covering them. The lobules are distinct- when the intralobular tissue forms complete septa around them ; if the septa are incomplete the lobules become confluent. Fine fibrous tissue surrounds the intralobular vein, and a delicate supporting network of flattened branched corpuscles exist within the lobule between the cells and the blood-capiUaries. Between the columns of the cells ran the radicals of the hepatic vein which open into the intralobular vein, and between the cells begin the radicals of the hepatic duct. Whether these radicals or bile capillaries have a definite mem- brana propria is undetermined. The intralobular Mle ducts are endothelial tubes with a large lumen, lined with columnar epi- thelium. The larger ducts are surrounded with circular unstriped muscle cells, and have a distinct mucous membranei of loose con- nective tissue lined with columnar epithelium, and containing mucous tubular glands. The lymphatics of the lobule originate in the spaces around the capUlaries of the lobules. GALL BLADDER is similar in structure to the large hepatic ducts, but the mucous membrane is thicker, and is thrown into folds and villous pro- jections. The muscular coat also is thicker, and is surrounded by connective tissue, and an outer layer ot peritoneum. 65 TRACHEA AND LUNG. Preparation. Distend the lungs of a recently killed rabbit or cat, through the trachea, with \ °/o solution of chromic acid, tie up the trachea and immerse it in a large quantity of chromic acid of similar strength. Change the solution for one of a ^"/o ^^ two days ; in a week cut in pieces, and remove to methylated spirit. Before cuttii^ sections, it is necessary that the embedding mass shall have thoroughly penetrated into amd filled up the interstices of the tissue, and so it is best to place the piece of lung to be embedded in the wax mass when it {i.e. the lung) is quite hot. In some cases it is as well to stain the lung with logwood, and pass it through alcohol and oil of cloves before embedding. Unless the interstices are filled up it is almost impossible to cut thin sections. To free the cut sections from wax, pass them through oil of turpentine before putting them into oil of cloves. Thin sections of lung injected through the pulmonary artery with Berlin blue, and through the trachea with J°4 solution of silver nitrate, should be made if possible, and treated in usual manner. Sections of trachea should also be made. Structure. (1) Of Traehea. (a) .4» eZa« Potir a little strong MNO.^ imtg a test tube, and add gradually dilute solution of albumin : albumin precipitated at point of contact vrith the acid, in the form of a fine ring. SEEUM ALBUMIN. Pebpabation. Dilute blood serum with water, add ether, shake up, filter and test filtrate with HNO3. Differs from egg albumin in not being coagulated by ether. Also differs from egg albumin in being easily precipitated by HCl, and in being easily soluble in excess of this acid. Serum Albumin, either in the coagulated or precipitated form, more soluble in excess of strong acid than Egg Albumin, All albumin is very slightly diffusible. EXPEBIMENT. Solution of albumin, to which salt has been added, should be placed on a dialyser, and the outside liquid tested for albumin, phosphates, and chlorides. 91 CLASS II.— DERIVED ALBUMINS. Insoluble in water and in solutions of NaCl, but are soluble in dilute acids and alkalies. Acid Albumin. If a small amount of dilute HCl or acetic acid be added to either egg or serum albumin, there is no precipitate or coagulation on heating. On exactly neutralising the solution, a flocculent precipitate is produced. The albumin has become insoluble in water and neutral saline solutions. It is soluble in acids and alkalies. Insoluble in NaCl solutions. AU Globulins are converted by dilute acids into acid albumin. Partial coagulation on boiling in lime water, and further precipitation on addition to boiled solution of CaClj,MgS04, or NaCl. Alkali Albumin. If solutions of albumin be treated with dilute alkali (NaHO), coagulation is prevented. Alkali albumin thrown down on neutralising solution, except in the presence of alkaline phosphates. To differentiate letween Aoid amd Alkali Alhv/mJm the following method is useful : — (1) Alkali albumin is not precipitated on exact neutralisation if sodium phosphate has been previously added. (2) Acid albumin is precipitated on exact neutralisation, whether or not sodium phosphate has been previously added. CASEIN. Smiila/r to alkali alhimin, but difEers in (1) yielding sul- phide when heated with KHO to 110°; (2) yielding phosphorus- containing body when digested with gastric juice. Obtained from milk by following process : — Dilute the milk with three to four times its volume of water, add slight excess of dilute acetic acid, and filter off the casein. To purify it, wash with alcohol and ether. Casein may also be prepared by adding to milk an excess of crystallized sulphate of magnesium, which causes it to separate out. 92 DERIVED ALBUMINS. Casein is slightly soluble in dilate caustic alkalies and acids. It is retained to a considerable extent in solution, by the pre- sence of alkaline phosphates. MILK. Examination op Milk. Examine* a drop of milk under the microscope with high power. See that it consists of fat globules of different sizes in a clear fluid. Add dilute acetic acid by irrigation, and observe the coalescence of the globules owing to the acid dissolving their casein membrane. Test the alkaline reaction of fresh milk ; it becomes acid on standing, owing to the formation of lactic acid , whilst the casein separates. The constituents whose presence is to be demonstrated are Oil or Fat, Casern, two kinds of AlTrumm, and Lactose or Milk Sugar. Fat. To a portion of milk add its own volume of KHO, and warm the solution gently; the casein' will be dissolved from the oil globules. Add ether, shake the mixture and allow it to stand. The fat wiU be dissolved in the ether, and will form with it a clear superstratum. Remove the transparent top layer with a pipette, evaporate off the ether, the oil will be left, and will give the oharaeteristiB greasy spot when dropped vpon paper. Casein. Dilute some of the milk with its own bulk of water ; add a little dilute acetic acid until a slight granular precipitate is formed. Warm 'the solution gently, and a copious flocculent precipitate will fall. Filter off, and label the precipitate A. ALBtnvitN. Boil the clear filtrate (from A), a coagulum of albumin will be formed. Filter this off, and label the precipitate B. Emaotly neutralise the clear filtrate (from B) with KHO, a precipitate of albumin which is soluble in acids is formed. Filter off precipitate, and label it C. Lactose. Test the clear filtrate (from C) by Trommer's test (KHO ami CuSO^ for sugar. To precipitate A in a test tube add nitric acid, the precipitate is dissolved ; boil, and when cold add strong Ammonia, the solution becomes orange-coloured (xanthoproteic test). DERIVED ALBUMINS. 93 To a second portion of precipitate A add sodium phosphate, the precipitate will be dissolved ; add dilute acetic acid to the solution till a neutral reaction is just obtained, no precipitate occurs ; add more acetic acid, a precipitate is thrown down, easei/n, or alkali aliv/mAn is present. Test the precipitate on filters B and C by boiling with Millon's reagent, a pink coloration will in each case be produced, showing that albumin is present. 95 VROTEIDS— (continued). CLASS III.— GLOBULINS. Insoluble in water : soluile m very dilute aeids and alkalies, soluble in l°/„ solution of NaCl and other neutral salts. Differ from natiTe albumins in not being soluble in distilled water, and from derived albumins in being soluble in neutral saline solutions. Are converted hy aeids and alkalies into acid — a/nd alkali — aliwithin respectively. (1) Globulin or Cktstallin. Obtained from the crystalline lens. (2) Myosin. Prepared from dead muscle by removing all fat, tendon, etc., and washing repeatedly in water, until the washing contains no trace of proteids, and then treating with 10°/o solution of NaCl which will dissolve a large portion into a viscid fluid, which filters with difficulty. If the viscid filtrate be d/ropped little hy little into a la/rge qucmtity of distilled mater, a white flocoulent precipitate of m/yosin mill occw. (3) FiBEINOPLASTIC GLOBTTLIN, OE PABAGLOBtTLIN. -Blood serum is diluted with 10 vols, of water, and GOj is passed rapidly through, the fine 'precipitate is collected on a filter, and washed with water containing COj. [Also by saturating serum with NaCl or MgSOj.] Very soluble in dilute saline solutions, from which it is pre- cipitated by COj, and dilute acids tV'/o- Its solution coagulated at 70°C. Even dilute acids and alkalies convert it into acid or alkali albumin. Can be used to form fibrin. (4) FiBKlNOGBN. General reactions similar to paraglobulin. Preparation by similar process from hydrocele fluid. Its characteristic property is that, when mixed with paraglo- bulin, it gives fibrin. 96 PEOTEIDS. (5) TiTELLIN. Obtained from yolk of egg. (6) Globin. The proteid residue of hsemoglobiii. CLASS IV.— FIBRIN, A soft wMte fibrous, and very elastic substance, obtained from blood-clot Ity washing with large amount of water. DifiEers from all other proteids, in having a filamentous struc- twe. Examine with microscope. Has svrmlwr cJiemical properties to coagidated albumin. Fibrin formed by combining (i) fibrinoplastic globulin and fibrinogen ; (ii) globulin from blood serum with hydrocele fluid. CLASS v.— PEPTONES. Are very soluble in water. Are not precipitated on adding acids or alkalies. Are not preaipitated on boiling. Insoluble in alcohol and ether, but are only precipitated with difficulty by alcohol. Are precipitated by mercuric chloride and lead acetate. With strong solution of NaHO and a trace of copper sulphate they give a red colour ; with excess of the salt a violet colour. Are very diffusible ; experiment with dialysing apparatus. Digestive Action of Pepsin. To some fibrin or albumin in a test tube add a trace of pepsin and a little HCl, ■2°/„, and warm gently ; in a few minutes filter, and test filtrate for peptones. 97 APPENDIX TO PR0TEID8. BLOOD. Alkaline reaction of blood. Coagulation retarded by freezing and presence of neutral salts. Experiment. Draw a few drops of blood from the finger intO' a watch-glass previously cooled in- a freezing mixture ; no coagulation at freezing temperature. A drop of blood a-dded to a little-saturated solution of sulphate of soda in a watch-glass ; the- blood does not coagulate. Examine the blood with spectroscope. Characteristic spec- trunL of o«;y-hsemoglobin. Action of *reducing agents on. blood', production of spectrum of reduced hsemoglobin. Action, of carbonic- oxide (CO) on the blood, alteration of spec- trum,, no change by actiom of reducing ageiLts on it.. Tests fob Bloods Formation of hsemin crystals, see pi 20. For quiaicum test see p. 103. NITEOGEWOUS BODIES OTHER THAN" PROTEIDS. Gelatin. Contains more nitrogen, and less carbon thau albuminv It is an amorphous, transparent substance. It is distinguished from the albumins by not being precipitated by ferrocyanide of potassium and by not being coagulated by heat ; ordinary gelatin, however, always contains albumin. It does not, if pwe, give the proteid reactions. It does not dialyse. It is insoluble in cold water, but swells up- to about six times its volume : it dissolves readily on the addition of very dilute acids or alkalies. Is soluble in hot water, B,nSf ottos a jelly on cooling; even when only l°/o of gelatin is present. Is precipitated by tannic acid, mercuric chloride, and alcohol. Not precipitated by dilute mineral acid, nor by acetic- acid. * A convenient form of redMomg agent is Stakes' Fluid, which is a solution of ferrous stdpliMe to mhich J^S^ffO lias Been added, after the previous addition tf svfficient taiitarie acid to prevent 98 NITROGENaUS BODIES OTHER THAN PROTEIDS. Bone. Consists of an organised matrix of oonmeotive tissue which contains gelatin and inorganic salts. Inorganic salts can he removed by digesting hone in hydro- chloric acid. The gelatinous matter left retains the form of bone. By long boiling in water, it is converted into a solution of gelatin. When bone is heated, the first action is to decompose the organic master, leaving a deposit of carbon. On farther ignition this carbon burns away, and only inorganic salts (principally calcic phosphate) are left. SoluMlity of the morganio salts in hydrooMorio acid. Mucin. Is the characteristic component of mucus. Preparation fi'om ox-gall, by acidulation with acetic acid and subsequent filtration. Can also be prepared from ox-gaU by precipitation with alcohol (afterwards dissolving in water and again precipitating by means of acetic acid). Can be obtained from mucus ,by diluting it with water, filter- ing, treating the insoluble portion with weak caustic alkali and precipitating the mucus with acetic acid. Mucin has ropy consistency. It is precipitated by alcohol and mineral acids, but dissolved by excess of the latter. Is dissolved by alkalies. Gives the proteid reaction with MiUon's reagent and nitric acid, but not with copper sulphate. Mercuric chloride and tannic acid give no precipitate with it. It does not dialyse. NON-NITEOGBNOUS COMPOUNDS. (CAEBOHYDEATES.) Staech (C6H,o05)„. Found in almost all plants. Is a soft white powder, consisting of rounded granules, having an organised structure. Size of granules varies according to the plant from which they come. Starch is insoluble in cold water, in alcohol, and in ether. On boiling with a large amount of water for some time, it becomes soluble and can be filtered. Solvble and msoTmile starch coloured Mue iy dilute solutions of iodine. CAEBOHYDKATBS, 99 On heating this compound with water, the colour disappears, but returns on cooling. Starch is obtained from potatoes, by scraping, and washing the scrapings, or from flour, by washing flour tied up in a bag. Glycogen (CeHjuOj). White amorphous powder resembling starch. Is soluble in cold water, twns Iromn mth iodme. Ferments or dilute^acids convert it into grape sugar. It occurs in the liver, and after death is found as grape sugar. Liver should be boiled with a small amount of water, and the solution should be then filtered and tested for grape sugar. For method of preparing glycogen, see p. 108. Gkape Sugar (CsHuOg). Occurs widely diflEused in the vegetable kingdom, occurs in diabetic urine, in the blood, etc. Is gbtained by treating honey with cold alcohol, the grape sugar remaining insoluble. Is easily soluble in "water. Is not nearly so sweet as cane sugar. I Not easily chaired by H2SO4. Seated with copper sulphate and KHO, euprous oxide is pre- cipitated. In making the experiment, to the solution of grape sugar add first the caustic potash, then the copper sulphate drop by drop as long as the precipitate formed readily dissolves on shaking the tube, then heat the solution gently. Quantitative estimation of grape sugar by Fehling's solution, or by saccharometer. A solution of grape sugar becomes brown on heating with KHO (Moore's test). It .is converted into carbonic acid and alcohol by yeast. C6H,A = 20,H50H+2GO,. Starch boiled for some time with water and H^SOj is converted into dextrin (British gum) and into grape sugar ; this solution to be tested with iodine, and also with potash and copper sulphate. Starch converted i/nto grape sugar by saliea. [To coUect saliva, fill the mouth with ether vapour. The saliva to be filtered.] Milk Sugar (Lactose, CuHj^Ou). Important constituent of milk. Is much less soluble in water than grape sugar. Only slightly sweet in taste. Reduces copper salts liTte grape sugar. 100 CAKBOHTDBATBS. Is obtained from milk by adding a few drops of HjSOj, warming and filtering ofE tbe curd. Also by diffusion. Test the solution obtained by both methods for milk sugar. Oils and Pats. Neutral substances. Composition, that of a compound ether. (Glycerin (Q^HjOj) being the alcohol.) They have a lower sp. gr. than water, from 0'91 to 0-94. They give a greasy stain on paper. Are insoluble in water. Easily soluble in ether. Glycbein (G3H5O3), a, viscid liquid, soluble in water and H3 alcohol, insoluble in ether. Has a characteristic sweet taste. Aeid potassivm sulphate heated with gVycerim, yields a,crolein : CjHjOs - 2H2O = G,Sfi. Olive oil, oleate of glycerin (SCGjgHgjOj)), or castor oil, heated G3H5 in a test tube with water, dissolves on addition of NaHO ; glycerin is liberated, and sodium oleate is formed. Both are soluble in water. Olive oil, heated in a basin with water and PJ)0 and well stirred, glycerin is liberated, and oleate of lead (lead plaster) formed. Olbin. Soda. Sodium Olbatk. Glycbbin. S(C,8H330,) + SNaHO = 3(G,8H330,) + C3H5O3 C3H5 Na, H3 Fat (stearate of" glycerin) heated in a test tube with water, melts, and on addition of caustic alkali saponifies, a stearate of sodium and glycerin forming. Sodium chloride added to this solution, soap (sodium stearate) separates out. Acid added to another portion, sodium stearate is decomposed. Stearic acid separates out. To another portion, add a solution of calcium ohloiide. Cal- cium stearate is precipitated. BlL£. An alkaline fluid, sp. gr. 1,018 to 1,020. Action of Bile on Oils and Fats. Bile shaken up with oil divides it into very small globules (an emulsion formed). ACTIONS OF BILE AND PANCKBATIC JUICE, 101 These can, under very slight pressure, pass through animal membranes ; oil alone cannot. EXPBEIMBNT. Take two filters, wet one with water and the other with bile, and pour a small and equal amount of oil on each. Oil passes slowly through the one wetted with bile, not at all through the other. * BUe acids, Glycocholio, and Taurocholio. (C«H,3NOs) (C^H^NSO,) Both give, feitA sulpJi/wrio aoid and sugar, a md eolov/r. Tests pok Bile. Pettenliofet's Test for Bile Salts. — ^Add a few grains of white sugar to solution of bile in test tube, shake well, add strong sulphuric acid, and cool. A reddish purple colour is produced. Chnelin's Test for Bile Pigments. — Place a drop of bile on a white plate, and add a drop of strong yellow nitric acid to it. A play of colours is produced. Green, blue, red, violet, and yellow, appear in succession. ACTION OF PANCKBATIC JUICE ON FOOD-STUFFS. 1. It converts Starch imto Grape Sugar. — Add some aqueous extract of pancreas to starch mucilage in test-tube, warm gently, and test solution for grape sugar. 2. It emuUioniaes Fat. — -Shake up some aqueous extract of pancreas with olive-oil in test-tube, an emulsion is formed. 3. It decomposes Fats, Uterating Fatty Acids, — If the emulsion be allowed to stand for some time, it becomes acid owing to the liberation of the fatty aoid. i. It converts Proteids into Peptones. — To boiled fibrin in test-tube,- add some glycerin extract of pancreas, diluted with l°/o solution of sodium carbonate, and expose to a temperature of 4;0°C for an hour ; then filter, neutralize filtrate with acetic acid, and test for peptones. 2'Ae main difference between the action of pancreatic juice and the action of gastric jmce oh proteids, is that pa/rt of the peptone formed by the former may be brohen np into leucin and tyrosi/n. * Urea (CON^Hj). The most characteristic constituent of urine. Its properties. — Soluble in alcohol and water. Crystallizes in transparent four-sided prismatic needles, ter- minated by one or two oblique facets. Evaporate solution on a glass slide, and examine with micro- scope. * See Appendix. 102 UKINE. Precipitation of urea by merourio nitrate in absence of NaCl, but not in presence of excess of the sait ; also by nitric acid. To strong solution add concentrated HNO^, wHch is free from any trace of nitrous acid. Urea nitrate (CONjHj HNO3) separates out in the form of six-sided tables. Examine with microscope. Strong solution of oxalic acid added to urea solution, urea oxalate (CON^Hj CjHaOJ separates out in the form of tabular or prismatic buidles. Examine with microscope. Ubic Acid (C5H4N4O3). Insoluble in cold water, yery slightly soluble in hot. Dissolves on addition of caustic alkalies, forming urates. The lithium urates the most soluble. Mwreceide test. — Add a drop of strong HNO3 to uric acid or a urate ; evaporate to dryness over water-bath, or at a temperature not exceeding 4:0°C. Alloxan (C^HjNjOj) is formed. Add a drop of ammonia solution, and the purple colour of murexide (CjHgNjOj) is produced. Healthy TTbinb is a perfectly transparent, amber-coloured liquid, with a peculiar, but not disagreeable odour, a bitterish taste, and slight acid reaction. Sp. gr. varies from 1,0J.5 to 1,025. Vrme tested for wea. Evaporate urine to half its bulk, and add strong HNO3 ; impure urea nitrate separates out. Quantitative estimation of urea. Decomposition by sodium hypobromite (NaBrO), in presence of caustic soda, the nitrogen collected and measured. CON2H4 -1- SNaBrO + 2NaH0 = 3KaBr + SHaO + NajCOj + Nj. MOKBID UEINE. ALB0MIN PKBSENT. If the urine be neutral or acid, the albumin is precipitated on boiling. If alkaline, render sHghtly acid with HNO3 or acetic acid, and boil. Coagulated albumin dissolved by caustic alkalies and reprecipi- tated by HNO3. A more delicate test.-^Acidiiy urine with acetic acid. Mucus will be precipitated if present. Filter, and add ferrocyanide of potassium to clear filtrate. A precipitate will be formed in pre- sence of albumin. Bile Pigment, oe Acid Pbbsent. Adopt Gmelin's test (p. 101). MOEBID UKINB. 103 Uric Acid Present. Employ the Murexide test (p. 102). Ueates Pbesbnt. The deposit dissolves on heating; sometimes reappears on cooling. Urates dissolve in caustio alltalies. -Uric acid separated on adding strong acids. Murexide test applied to the deposit. Phosphates I^esent. The phosphates may be in solution, or form a deposit. If in solution the urine is acid. On Periling urine, phospliates are deposited, the deposited phosphates ieing solulle in iceak acid. Phosphates insoluble in caustic alkalies. Oxalates Present. The deposit is soluble im SCI, but insoluble in acetic acid. Crystalline form. Sugar Present (Diabetes). Sp. gr. generally high, 1,030 to 1,C50. To small a/mount of urine, add caustio soda, or potash ; tJien a, fern drops of copper sulphate. Shake up, and heat. The orange-eulowed suboxide of copper (^Cu^O) is precipitated. If no grape sugar be present, or too much copper sulphate be added, a black precipitate of cupric oxide (CuO) is produced. Quantitative estimation of grape sugar by Fehling's solution (Trommel's test). Diabetic urine boiled with caustic potash or soda becomes brown (Moore's test). . Estimation of sugar by fermentation. — Take sp. gr. of urine before and after fermentation. Each degree of sp. gr. lost by the urine represents one grain of sugar per ounce of -urine (Roberts). Sugar may also be estimated by adding yeast to urine; and collecting the COj evolved. The COj is a measure of the amount of sugar present. Blood Present. Examine the deposit formed on standing, with the microscope, for blood corpuscles ; add to another portion a drop of tincture of quiaicum, and about a drachm of ozonic ether, a blue colour will appear at the junction of the fluids. 104 ANALYSIS OF UEINAET CALCULI. Pus Present. Umamine deposit with the mieroseope. Add caustic potash, the urine becomes stringy. ANALYSIS OF UEINAET CALCULI AND DEPOSITS. If a calculus, ignite a small portion on platinum foil. If it burns aw&y completely, it is probably uric acid. Apply muiexide test. Boil the powdered calculus with distilled water, or, if. a urinary deposit, with the supernatant mine, and filter. INSOLUBLE PORTION. Phosphates, calcium oxalate, uric acid. Boil with a few drops of hydrochloric acid, and filter. Insolutle. Uric acid. Apply murexide test. Soluble. Phosphates or calcium oxalate. Add excess of ammonia, and then acetic acid in excess : a precipitate remaining undissolved is calcium oxalate. To the clear liquid, whether filtered or not, add ammonia: a precipitate indicates the presence of phos- phates. SOLUBLE POKTION. Ubatbs. Mostly deposit on coohng. Test for urate of ammonia by boiling with potash to dem onstrate the presence of ammonia, and by the murexide test for the uric acid. APPENDIX. The injection of blood-vessels and lymphatics can be effected either by means of a simple syringe or by the pressure of a column of air, water, or mercury. These methods are described at length in the "Handbook for the Physiological Laljoratory," pp. 97 — 103 (by Dr. Klein), and elsewhere. The fluids employed are : — (fi) Berlin blue, eilher dissolved or suspended in water, or in solution in gelatin. A 2% solution of the material is chiefly employed. (6) Cminine, either dissolved or suspended in water, or in solution in gelatin. (c) Nitrate of silver used in a 0"25 or 0'5% solution. Warm stages of various kinds are in use. The simplest is a glass slide to which a perforated circular plate of copper is attached with cement: thi§ is joined to a projecting rod of the same metal. The rod communicates heat from a spirit lamp to the plate, upon which is placed the specimen of blood to be examined. It is best to use two large cover glasses, arranged as a " moist chamber" ; one has upon it the blood to be examined, the other is edged round with oil ; when applied to each other the oil prevents the fluid of the blood from evaporating, and under these circumstances the movement of the colourless corpuscles can be watched for some time. The temperature is regulated by placing a small piece of cacao-butter on a flattened portion of the rod near the copper disc. When the butter melts, it is a, warning to remove the spirit-lamp. Strieker's warm stage is more elaborate ; it is provided with a thermometer which accurately regulates the temperature. Of this instrument there are several varieties (see " Hdbk. Phys. Laboratory," p. 7, and plates). It is usually arranged so that gases can be introduced to act upon the blood under examina- tion. Action of Gases on the Blood. — The warm stage is to be used, a ring of putty being placed round the central chamber. A drop 106 APPENDIX. of blood diluted with 0'75°l„ saline solution is placed on a cover glass, which is then inverted upon the putty. The chamber thus becomes air-tight, and should be kept moist by placing a drop of water in it. The stage is then put into communication with the apparatus used for generating the required gas by means of indiarubber tubing. Action of Ga/rbonic Acid Gas. — The preparation is brought into focus, and the gas is allowed to pass through the chamber. Mumcm. — The red blood-corpuscles, which had become crenate from "the. action of the salt solution, again acquire a smooth out- line, owing to the swelling up of the parts between the projections. On admitting air to the chamber the corpuscles again become crenate. The nuclei in the white corpuscles become more dis- tinct. Amphibia. — The nuclei in the red corpuscles appear more distinct, owing to the coagulation of the substance surrounding the nucleus. Action of Chloroform on the Blood. — Preparation as for gases. The red corpuscles become globular, the hsemoglobin being finally dissolved and discharged into the plasma ; the blood, when seen with the naked eye, being transparent (lake) and no longer opaque. Action of Electricity on the Blood. — The blood is placed on a slide in such a position that when it is covered it spreads between two poles of tinfoil situated six millimetres apart, which are connected with the secondary coil of an induction apparatus. < After a succession of induction shocks the red corpuscles lose their smooth outline, become crenate, then like mulberries, and finally horsechestnut-shaped. They swell up, and ulti- mately become decolorised. The whAte corpuscles swell up and disintegrate, their granules exhibiting molecular movements. With a constant current from a single Bunsen's cell the red cor- puscles at the positive pole undergo changes which correspond to those exhibited under the action of an alkali, and at the negative pole of an acid. The colourless corpuscles assume a spheroidal form, the amoeboid movements being resumed as soon as the stimulus has passed. The Action of AlkaUes on Blood. — ^A mixture of 2cc. of caustic potash in lOOOcc. of saline solution causes both red and white blood-corpuscles to swell up, burst, and disappear. The red corpuscles appear to be more rapidly affected than the white. APPENDIX. 107 The Action of Alcohol. — A mixture of one-third spirit and two- thirda water, acting upon amphibian blood, causes the nucleus to swell, and brings into view the nucleolus in the red corpuscles. It also renders the nuclei of the colourless corpuscles more evident, whilst one or more delicate and clear " blebs " grow from the periphery of the white corpuscle. These ' ' blebs " appear to consist of some colloid substance, into which endos- mosis rapidly takes place. {Rutherford.) The Method of Feeding the Colourless Oorp^iscles. — The prepa- ration of blood on the warm stage is irrigated with carmine, vermilion, or anilin blue, in a finely divided state (for method of preparation see " Handbook for the Physiological Labora- tory," p. 10), or with milk. The white corpuscles will be found after a short time, to have ingested some of the finer particles. The particles are taken into the substancq of the corpuscle by the union around it of two of the protoplasmic processes, and they thus lie at first close to the periphery of the cell, being carried at a later period nearer to its centre. Ciliary Motiori. — The epithelium scraped from the roof of a frog's mouth, or epithelium obtained from the mucus of the nose, may be employed. The gills of the ordinary mussel or oyster, and the epithelium lining the alimentary canal of the earthworm, are also well adapted for the demonstration of ciliary motion. The examination is to be made in normal saline solution, the preparation being slightly teased previous to covering. The highest available power should be used. Effects of Reagents. — Dihvte alkalies slow, and then stop the movements. If the cilia are working slowly, or have stopped in a preparation which has just been put up, the-careful addition of a very dilute solution of caustic potash or dilute acetic acid, or the passage over it of carbonic acid, or an electric shock, will generally renew or accelerate the movements for a short time, — the ultimate effect, however, being to destroy the ciHa. Carbowia acid first accelerates, then slows, and finally stops the ciliary action, the movements recommencing if air is allowed to take the place of the carbonic acid. Chloroform retards and finally stops ciliary action ; the move- ments recommencing on the admission of air, if the vapour has not been applied for too long a period. Warmth accelerates the action of cilia which were previously 108 APPENDIX. moving slowly, the movements ceasing at a temperature -which is sufficient to destroy the vitality of the cells. Prepa/raUon of Glycogen. — Apparatus necessa/ry. A solution of potassic-mercuric iodide made by precipitating a solution of mercuric chloride with potassium iodide, washing the precipitate and adding it to a boiling solution of potassium iodide till the latter is saturated. Any precipitate which occurs on cooling is to be filtered oflF. Dilute hydrochloric acid. Methylated spirit, a large bottle ; ether ; absolute alcohol. Large filter and Swedish filter papers. Large knife ; capsule ; several beakers ; distilled water ; ice. Mortar and pestle ; large Bunsen's burner. Glycogen, usually obtained from the liver of animaJs, is also present to a considerable extent in the muscles of very young animals. To prepare glycogen, it is best to use the liver of a rabbit. The animal should be large, and it must have been well fed on a diet of grain and sugar for some days, preferably weeks, previously. The rabbit should have a full meal of grain and sugar about two hours before it is killed, in order that it may be in full digestion. Before destroying the animal the capsule is to be filled with water, which is kept briskly boiling by means of the large Bunsen's burner. The rabbit is killed either by decapitation or by a blow on the head, and the abdomen is then rapidly opened, and the liver is torn out, is chopped up as quickly as possible with the knife, and is thrown into the boiling water. It is important that this operation should be performed within half a minute of the death of -the aninjal, and that the water should not be allowed to fall below the boiling-point. The liver is to remain in the capsule for five minutes ; it is then poured into a mortar, the liquid, being returned to the capsule. The liver is then reduced to a pulp, and is again boiled in the capsule for ten minutes. The liquid is filtered, and the filtrate is rapidly cooled by placing the vessel in iced water. The albuminous substances in the cold filtrate are precipitated by adding potassio-mercuric iodide and dilute hydrogen chloride alternately as long as any precipitate is produced. (The albumin may also be destroyed by boiling in a strong solution of sodium sulphate.) The mixture is then stirred, is allowed to stand for five minutes, and is filtered. Alcohol is add«d to this second filtrate until glycogen is pre- APPENDIX. 109 cipitated {i.e., until about 60% of absolute alcohol has been added. The precipitate is then filtered off, and is washed with weak spirit, strong spirit, absolute alcohol (two or three times), and finally with ethgr. It is then dried on a glass plate at a moderate heat, and if pure should remain as a white amorphous powder. If the water has not been completely removed, the glycogen T^ill form a gummy mass ; in this case it must be again treated with absolute alcohol. Preparation of Leucin and Tyrosin. — These bodies may be obtained by digesting fibrin for ten to twelve hours with pancreatic juice. The albumin is precipitated by slightly acidulating, boiling and filtering the solution. The filtrate is then evaporated to a small bulk, and heated with strong alcohol to precipitate the peptones. On again filtering, an extract is obtained from which leucin and tyrosin crystallise. The two bodies can be separated from each other by the addition of boiling alcohol, in which leucin is soluble, and from which it can be recrystallised. (Burdon Sanderson.) Preparation of Bilin. — -Mix bile, which has been evaporated to one-fourth its bulk, with animal charcoal, evaporate to perfect dryness on a water-bath, and extract it, whilst still warm, with absolute alcohol. The alcoholic filtrate should be colourless ; if this is not the case, more charcoal must be added. The alcohol is distilled off, and the dry residue is treated with absolute alcohol. The alcohol is then filtered off, and to the filtrate anhydrous ether is added as long as a precipitate is thrown down. The solution and precipitate are to be set aside in a closely-stoppered bottle for some days, when crystals of bilin will be produced. If the reagents were not perfectly anhydrous, a gelatinous mass will be formed, but no crystals. Bilin consists of glycocholic and taurocholic acids, which may be separated by dissolving the bUin in water, and adding first solution of neutral lead acetate and then a little basic lead acetate. This combines with the glycocholic acid, and forms an insoluble lead glyco- cholate. Filter, and add to the filtrate lead acetate and ammonia, and a precipitate of lead taurocholate wUl be formed, which may be filtered off. In either case the lead may be got rid of by suspending or dissolving in hot alcohol, adding hydrogen sulphide, and filtering. Prepa/ration of Cholesterin. — ^Pulverised gall stones are ex- 110 APPENDIX. tracted with boiling alcohol, and the extract is filtered whilst boiling. Crystals of cholesterin separate out from the filtrate when cool. These may be purified by boiling with an alcoholic solution of caustic potash, washiag with cold alcohol, and then with water ; dissolTing in a mixture of alcohol and ether, and allowing it to evaporate. DEVELOPMENT OF TEETH. Preparation. — The foetus of a new-bom rat is decapitated, and its head is placed in a large excess of \% chromic acid for a week ; it is then transferred to spirit. The lower jaw may then be removed, and embedded in the ordinary way ; the sections should be stained in hsematoxylin and in carmine. (1) The first rudiment of a tooth appears as a solid prolonga- tion of the stratified epithelium, which grows downwards from the surface into the mucous membrane. This process of epi- thelium is the prmiary enamel organ. (2) The enamel organ becomes invaginated at its deep end by a mass of tissue derived from the mucous membrane, called the embryonal tooth papilla. The primary enamel organ is thus converted into the erho/mel cap covering the tooth papilla. (3) The papilla is vascular and is composed of a network of nucleated cells; it forms the pulp, and by means of its odontoblasts forms the dentine. (4) The Odonto- blasts appear on the papilla as a peripheral stratum of large cells arranged vertically. (6) The dentine is formed by the elongation and subsequent calcification of the distal extremities of the odontoblasts, whilst (6) the dentinal fibres are derived from processes of cells wedged in between the odontoblasts. (7) The tooth sac, or the mucous membrane which immediately surrounds the enamel cap and tooth papilla, gradually grows over the former, and separates it from its connection with the surface epithelium. (8) The ena/mel cap consists externally of (a) columnar ceUs, more internally of (6) polyhedral cells, followed by (c) flattened epithelial cells in the centre, and again of (d) poly- hedral, with (e) columnar cells most internally — i.e., nearest to the tooth papilla. (9) The enamel cap is limited both externally and internally by a membra/na propria. (10) The enamel cap becomes divided into an inner and outer membrane by the transformation of the middle layer (8c) into a transparent tissue. APPENDIX. Ill The wmer membrane is composed of columnar cells, the enamel cells, in contact with the dentine ; each is a loiig hexagonal prism, and is nucleated at its lower part. Outside the layers of enamel cells ate one or more rows of small polyhedral cells, forming the stratum intermedium. The outer m,emhratie is composed of several layers of epithelial cells. (11) The enamel is formed by the enamel cells of the inner membrane elongating at their distal extremities ; the elongated portion is transformed rapidly into enamel. (12) The cells of the stratum intermedium are used for the regeneration of the enamel. (13) The cells of the outer epithelium produce the enamel cuUcle. (14) The cement is formed from the tissue of the tooth sac in exactly the same way as sub-periosteal bone is developed, (15) During the stage of the primary enamel organ (i) a lateral process grows out from the epithelial cells, which represents the rudiment of the enamel organ of the permanent tooth {sac of reserve). (16) The Per- manent teeth are developed on exactly the same plan as the deciduous set. (Klein.) Pa/per " boat " for Embeddmg in Wax may be made by taking a, piece of stout paper, six inches long and three broad, and doubling it into three folds lengthwise, and then doubling down flaps of two inches from each end. The paper is then opened out, and the lateral folds form the sides of the boat. To arrange the ends, each flap is marked off into two equal parts, one inch of which is for the end, and the other, after the comers are arranged, forms an external flap to keep the folding necessary for this in place. 112 APPENDIX. OlassiflcaUon of Staining Fluids. — ^Mr. J. W. Groves, in an excellent paper read before the Quekett Microscopical Club, gives the following clasaifloation of staining fluids : — f Carmine with excess of ammonia. J Eosin (Dreschfeld). j Molybdate of ammonia. (This requires ( the action of light.) A. General stains. B. Selective stains. Carmine (Beale). Borax carmine (Golding Bird); Logwood (Golding Bird). Logwood acid solution (Schafer). Indigo carmine (Tiersch). AniUn blue (Heidenhain). ^Picric acid. ( Gold chloride. baa . ij .3 -2 ;S °"B § ;^ i Silver nitrate, .9 a* „, t„ I Osmic acid. 'M: Which will stain in i „ ,,, , , . , the mass and harden I ??3i°„'?lTl^: at the game time, I Chloride of palladium. 'Molybdate of ammonia and carmine. Picrocarmin (Schafer). Chloride of paUadixun and carmine. Carmine and indigo carmine. Logwood and anilin blue. Gold chloride and logwood. Silver nitrate and logwood. Silver nitrate and gold chloride. f Osmic acid. -i \ Picric acid. \ Alcohol + borax carmine. / Alcohol + Golding Bird's logwood. (Alcohol -j- eosin. APPENDIX. 113 Magnifying Powers of Microscopes. — Messrs. Parkes furnish the following table of the magnifying power of some of their microscopes, which may be taken as a type of the ordinary instruments : — Approximate magnifying power with Eyepieces : ABC 1 G 1 1 145 29 11 1 inch Draw-tube closed .... Ditto if drawn out, add for each inch 65 13 95 19 18° i inch • Draw-tube closed .... Ditto if drawn out, add for each inch 100 20 125 26 147 30 183 37 225 45 280 66 30° 4 inch 1 Draw-tube closed .... Ditto if drawn out add for each inch 35° i inch • Draw-tube closed .... Ditto if drawn out, add for each inch 260 52 380 76 580 116 70-^ i inch 1 Draw-tube closed .... Ditto if drawn out, add for each inch 333 66 486 97 743 148 95° INDEX. 117 INDEX. Acetic acid, action ou blood coi- ])uscles, 20 Acid albumin, 91 Acrolein, 100 Adenoid tissue : In lymphatic glands, ,70 In spleen, 70 In thymiiB, 83 In tonsils, 47 Adipose tissue, 27 Adrenals, 84 Agminated glands, 51 Air-cells, S6 Air-tube, S6 Albumins, classification of, 87 Acid, 91 Alkali, 91 Casein, 91 Egg, 89 Serum, 89 Tests for, 87 Alcohol absolute, for hardening tissues, 6^.13 Alcohol methylated, for hardening tissues, 6, 13 Alimentary tract, 45 — 54 GaU bladder, 54 Large intestine, 51 Liyer, 53 CEsophagus, 47 Pancreas, 53 Salivary glands, 45 Small intestine, 51 Stomach, 49 Teeth, dcTelopment of, 110 periods of eruption, 78 Btmcture of, 77 Tongue, 45 Tonsils, 47 Alkali albumin, 91 Alloxan, 102 Ammonia molybdate (dye), 12, 112 picrocarminate (dye), 11, 112 urate, test for, 104 Amoeboid morement, 19 Amphibia, blood of, 20, 106, 10 Ampullae, 76 Auilin dyes, 12 black, 12 blue, 12, 112 Anterior roots, 40 Apparatus nebessary for the histo- logical course, 18 " Apparatus necessary for physio- logical chemistry, 86 Appendices epiploiose, 51 Aqueous humour for examination of fresh tissues, 5 Areolar tissue, 26 Arteries, 43 Articular cartilage, 29 Auditory hairs, 76 Auditory nerve, 38 Auditory organ, 75, 76 : see liar. Axis cyunder, 37 B. Basilar membrane, 75 Berlin blue for injecting, 105 Bichromate of potash, 6 ammonia, 6 BUe, action of, 100 BUe acids, 101, 109; tests fot in urine, 102 Bile pigments, 101;, tests for in urine, 103 Bilin, preparation of, 109 Birds, blood of, 20 Bladder, structure of, 63 Blood, 19, 20, 97 ; 105—107 Action of acetic acid on, 20 alcohol, 107 alkalies, 106 boracic acid, 20 carbon monoxide, 97 carbon dioxide, 106 chloroform, 106 cold, 97 electricity, 106 tannic acid, 20 water on, 20 118 INDEX. Blood : Coloured corpuscles, 19, 105-107 Golourlesscorpu8cleB,19,105-107 Hsemln crystals, metho d preparation, 20 Hsemoglobin crystals, method of preparation, 20 Method of feeding colourless corpuscles, 107 Spectrum of, 97 iTeataf 0^103 Blood serum for examination of fresh tissues, 5 Blood-vessels, structure of, 43 Boat for embedding. 111 Bone, structure of, 31, 32 developmeut m cartilage, 32 membrane, 32 chemistry of, 98 Boracic acid, action of on blood, 20 Bowman, glands of, 79 sarcous elements of, 35 Bronchi, structure of, 56 Brticke, disdiaclasts of, 36 Brunner's glands, 51 Cacao butter,, 8 Caecum, 51 Calcium oxalate, test foTj 103, 104 Canada balsam, preparation of, 14 Canaliculi, 31 Capillaries, structure of, 43 Capilliform processes, 76 Caput comu, 40 Carbohydrates, 98-100 Cardiac mnscler 36 Carmine, Scale's preparation of, 11 Oolding Bird's, 11 for injecting, 105 Cartilage, hyaline, 29 elastic, 30 fibrous, 29 Cartilage cells, 29 Cartibge matrix, 29 Casein, 91-93 Cement, development of, 11 structure of, 78 Central cells of stomach, 49 Cerebellum, 42 Cerebrum, 41 Cervix comu, 39 Cholesterin^ 109 Chromic acid and spirit as harden- ing agent, 6 Ciliary motion, 22, 107 ESect of dilute alkalies, 107 carbon dioxide, 10 7 chloroform, 107 electricity, 107 wannth, 107 CUiated epithelium, 22, 107 Circumvallate papillse, 45 Clove oil, 13 Cochlea, 75 Cohnheim's fields (areas), 36 Collecting tubes of kidney, 61 Colon, serous coat, 61: muscular coat, 51 Columnar epithelium, 21 Commissures of cord, 39 Composition of proteids, 87 . Connective tissues, 25-33' Adipose tissue, 27 Areolar tissue, 26 Bone, 31-33 Elastic cartilage, 30 Elastic tissue, 26 Fibro cartilage, 29 Grelatinous tissue, 27' Hya&e cartilage, 29 Tendon, 26 White fibrous tissue, 25 Connective tissue corpuscles in tendon, 26 ; in cornea, 71 Contour lines, 77 Contractile discs, 35 Convoluted tubes of kidhey, 61 ■•Corium, structure of, 57 Cornea, 71 Comioula laryngia, 30 I Comna of spiaaloord, 39 I Corpus luteum, 67 Corti, organ of, 75 Corti, rods of, 76 Cortex cerebelli, 41 Cortex cerebri, 42 Costal cartilage; 29 Cover glasses, 13 Crista acustica, 76 Crusta petrosa, development of, 110 structure of, 78 Crystallia, 95 Crypts of Lieberkiihn, 51 Cutis vera, structure of, 87 Cutting sections, method of, 7 D. Dammar vamiah, preparationof, 14 Deiter, cells of, 41 INDEX. 119 Dentine, development of, 111 structure of, 77 Derived albumins, 91 Descemet, membrajie of, 71 Development of bone, 32, 33 of teeth, 110, 111 Dextrin, 99 Diabetic urine, tests for, 103 Digestive action of pepsin, 96 Saliva, 99 Pancreatic juice, 101 Digestive tract, 45-o4; see Alimen- tary Tract. Discus proligerus, 67 Disdiaclasts, 36 Ductless glands : Adrenal, 84 Pituitary body, 83 Pineal gland, 84 Thyroid, 83 Thymus, 83 Ductus cochleae, 75 Dytikius marginalis, 35 Ear, 76 Ampullae, 76 Cartilage of, 30 Cochlea, 75 Membranous semicircular ca- nals, 76 Nerve, 38 Organ of Corti, 76 Egg albumin, 89 Tests for, 89 Elastic cartilage, 30 Elastic coats of arteries, 43 Elastic membranes of cornea, 71 Elastic stripe, 26 Elastic tissue, 26 Embedding, method of, 7, 8 box. 111 Embryonal cartilage, 29 tissue, 27 Bmulsification, 100 Enamel, 77 Cap, 110 Cuticle, 111 Development of, 111 Organ, 110 . , End bulbs, 57 Endochondral bone, 33 Endomyaium, 35, 36 Endonenrium, 37 Endothelium, 23, 44 Eosin, 12,112 Epidermis, 57 Epididymis, 65 Epiglottis, 30 Epineurium, 37 Epithelium of arteries, 43 Ciliated, 22, 64, 68, 107 Columnar, 21, 46, 49, 51, 53, 54 61, 63, 71 Glandular, 2I, 53, 61 Spheroidal, 49, 54 Squamous, 21, 47 Stratified, 45, 47, 67, 59, 63 Tesselated, 56 Transitional, 22, 63 B. Fallopian tubes, 68 Eascicnli of muscle, 36 Fat, structure of, 27 Chemistry of, 100 Action of pancreatic juice on, 101 bile on, 101 Test for, 92 Fehling's test for sugar, 99; 103 Solution, 99 Fermentation test for sugar, 99, 103 Fibres of muscle, 35 FibriUae of muscle, 35 Fibrin, 96 Fibrinogen, 95 Fibrinoplastin, 96 Fibro cartilage, 29 Fibrous tissue, white, 25 Filiform papillae, 45 Fish, blood of, 20 Flogel, granular layer of, 36 Freezing, method of, 9 Fresh tissues, examination of, 5 Fungiform papHUe, 45 Funiculi of nerve, 37 G. G-AIiACTOPHOKOUS ducts, 81 Gall bladder, 54 Ganglion cells, 39 Gelatin, 97, 98 Gelatinous tissue, 27 Genito-urinary organs, 61-68 Bladder, 63 Fallopian tube, 68 Kidney, 61 Ovary, 67 120 INDEX. Genito-urinary organs : Prostate, 63, 64 Testes, 65 TTreter, 63 Uterus, 67 Tesiculse seminales, 65 Genninal vesicle, 67 Glands : Agminate, 51 Adrenal, 84 Bowman?, 79 Brunner's, 61 Kidney, 61 Lieberkiihn's, 51 Liver, 63 Mammary, 81 Mucous, 46, 68, 79 (Esophageal, 47 Pancreas, 63 Peptic, 49 Peyer's, 61 Pineal, 84 Pituitary, 83 Salivary, 46 Sebaceous, 57 Solitarise, 51 Spleen, 70 Sweat, 57 Testes, 66 Thymus, 83 Thyroid, 83 Tracheal, 56 Glandular epithelium, 21, 63, 61 Glass slides, 13 Ghsson's capsule, 53 Globin, 96 .Globulin, 95 Glycerin, method of mounting in, 23 Chemistry of, 100 Test for, 100 Glycogen, 99 Preparation of, 108 GlycochoUc acid, 101 Preparation of^ 109 Gkneliu's test for bile pigment, 101 Goblet cells, 46 Gold chloride, 6, 13, 112 Graffian follicle, 67 Granular layer of Cerebellum, 42 Muscle, 36 Retina, 73 Grape sugar, 99 Grey matter of cerebrum, 41 Grey matter of cord, 39 Guiaioum test for blood, 103 H. HajMATOXTMN, preparation of, 10 Hsemin crystals, preparation of, 20 Haemoglobin crystals, 20 Hair, structure of, 59 auditory, 76 cells, inner and outer, 76 Hardening agents : Absolute alcohol, 6 Bichromate of ammonia, 6 potash, 6 Chromic acid and spirit, 6 I'reezing, 9 Gold chloride, 6 Methylated spirit, 6 Miiller's fluid, 6 Osmic acid, 6 Picric acid, 6 ^ Hassall, corpusctes of, 83 Haversian canals, 31, 33, 78 interspaces, 31 lameliee, 33 spaces, 31, 33 Heart muscle, 36 Heidenhain, semilunes of, 46, 53 Henle, looped tubes of, 61 Hensen's cUscs, 36 Hepatic vein, distribution of id liver, 54 Hyalin cartilage, 29, 32 I. , Henm, structure of, 51 Infundibulum, kidney, 61 lung, 66 Injecting, method of, 105 Intermediary cartilage, 29, 32 Interstitial discs, 35 Intervertebral substance, 29 Intramembranons bone, 33 Intralobular veins, 54 Involuntary muscle, 36 Iodine test for glycogen, 99 starch, 98 Iodised serum, 5 Irrigation, method of, 19 J. Jejunum, structure of, 51 K. Kidney, structure of, 61 Krause, membrane of, 36 INDEX. 121 L. Lactiferous ducts, 81 Lactose, 92, 99 Lacunee of bone, 31 Large intestine, structure of, 51 Lateral discs, 36 Lead plaster, preparation of, ] 00 Leucin, 101 ; preparation of, 109 Leucocytes, 19, 106; method of feeding, 107 Lieberkiihn's crypts, 51 Lifter for sections, 14 Limbus, 75 Lithium urate, 102 Liver, structure of, 53 Looped tubes of Henle, 61 Lung, structure of, 56 Lymph sinuses, 70 Lymphatic capiUarieE, 69 glands, 69 perivascular, 42 trunks, 69 M. Macula germinativa, 67 Magnifying power of microscope, 113 Halpighian bodies, 70 capsules, 61 layer, 57 tufts, 61 Mammary gland, 81 Max Schultze's cells : Muscle, 36 Olfactory, 79 Medulla of bone, 32, 33 Medullated nerve fibre, 37 Medullary cavity, formation of, 33 sheath of nerve, 37 Method of cutting sections, 7-10 embedding tissues^ 7, 8, 10 examihing fresh tissues, 5 hardening tissues, 5-7 mounting tissues, 13-14 in Canada balsam, 14 glycerin, 14, 28 staining tissues, 10-13 teazing. 10 Methylated spirit for hardening, 6 Microscopes 15 magnifying powers of, 113 Microtomes^ 8-10 Milk, examination of, 92 Milk sugar, 92, 99 MiUon's test for proteids, 87 Modiolus, 75 Molecular layer of cerebellum, 42 ; of retina, 73 Moore's test for sugar, 99, 103 Mounting, method of, 13 Mounting solutions : Canada balsam, 14 Dammar, 14 Glycerin, 14 Mucin, 98 Mucous glands, 46, 68, 79 Mucous tissue, 27 MiiUer, fibres of, 74 Mtaier's fluid, 6 Murexide test, 102, 104 Muscle, cardiac, 36 cell (corpuscle), 36 oompartment, 36 striated, 35, 36 unstriated, 36 Muscularis mucosee, 47, 50 K Nabothi, ovula, 67 NaU, structure of, 59 Nasal mucous mpmbrane. 79 Nasmyth's membrane, 77 Native albumins, 89 Nerves, medullated, 37 non-meduUated, 38 Nerve centres : Cerebellum, 42 Cerebrum, 41 Cerebro-spinal, 38 Spinal cord, 39 Neurilemma, 37 Neuroglia, 39, 41, 42 Nitrate of urea, 102 Nitrogenous bodies, 87-98 Non-nitrogenous substances, 98-100 Nucleated sheath of Schwann, 37 0. Odontoblasts, 110 CEsophagus, 47 Olein, 100 Olfactory nerve, 38 Olfactory organ, 79 ; cells, 79 Olive oU, 100 Oils and fats, 100 Optic nerve, 38 Osmicacid, 6, 112 Ossifying cartilage, 29, 32 Osteoblasts, 33 Osteoclasts, 33 122 INDEX. Osteodentin, 78 Osteogenetic layer of periohon- drium, 33 Osteoporosis, 33 OTalbumin, 89 Ovary, structure of, 67 Ovula Nabothi, 68 Ovum, 67 Oxalates in urine, test for, 103, 104 Oxalate of urea, 102 Pacinian bodies, 64 Pancreas, structure of, 53 digestive action of, 101 Papillae of kidney, 61 sidn, S7 tongue, 45 Paraffin wax and lard for embed- ding, 8 Paraglobulin, 95 Parotid gland, 45 Pepsin, 96 Peptic cells, 49, 50 Peptic glands, 49 Peptones, 96 Pericbondrium, 29, 32 ' Perimysium, 35, 36 , Perineurium, 37 Periosteum, 32 Perivascular lymphatics, 42 Pettenkofer's test for bile acids, 101 Peyer'e glands, 51 Phalanges (ear), 76 Phosphates in urine, teat for, 103, 104 Picric add, 6, 112 Picrocarmin, or picrocarminate of ammonia, 11, 112 Pigment, 22 Pineal gland, 84 Pituitary body, 83 Plasmatic cells, 27 Plexuses nerve of cornea, 71 Portal vein, distribution of in liver, 54 Posterior roots, 40 Primitive nerve sheath, 37 band, 37 fibrils, 38 Prostate, structure of, 63 Proteids, classification of, 87 Composition of, 87 Native albumins, 89 Proteids, Derived albumins, 91 Fibrin, 96 Globulins, 95 Peptones, 96 Tests for, 87 Action of gastric juice on, 96 Actionof pancreatic julceon,10I Purkinje, cells of, 42 Purpurin, 12 Pus in urine, test for, 104 Pyramids of Eerrein, 61 E. Eanvier's microtome, 9 nodes, 37 Bazors, 8 Reagents for histology, 18 physiolopcal chemistry, 86 Reagents, effect of, on blood cor- puscles, 20, 106 Rectum, serous coat of, 51 ! Reissner, membrane of, 75 ' Reserve sac, 111 , Respiratory tract : i Bronchus, 56 1 Lung, 56 Trachea, 55 Rete Malpigmi, 57 mucosum, 67 testis, 65 Reticular membrane, 76 Retina, 73 Roberts' test for sugar, 103 Rolando substantia gelatinosa, 40 Rosein, 12 a Salinb solution, 5 Saliva, 99 Salivary glands, 45 , Salivary cells, 46 Santorini, cartilages of, 30 Saponification, 100 Sarcolemma, 36 Sarcous elements, 35 Scala vestebuli, 75 Schreger, lines of, 78 Schwann, sheath of, 37* white substance of,- 37 Sebaceous glands, 67 Semicircular canals, 76 SemUunes of Heidenhain, 46 Seminal cells, 65 Septum transversum, 76 Seralbumin, 89 INDEX.- 123 Seralbumin : Tests for, 89 Serous membranes, endothelium of, 23 Sesamoid bones, 29 Shnrpey, perforating fibres of, 31, 78 Silver nitrate, 12, 105 Skin, structure of, 57 SmaU intestine, structure of, 51 Sodium hjpobromite, urea test, 102 Sodium oleate, 100 Softening fluids, 7 Solitary glands, 51 Spermatozoa, 65 Sphincter uteri, 68 Spinal cord, 39 Spiral groove, 75 Spiral lamina, 75 Spiral ligament, 75 Spleen, 70 Squamous epithelium, 21, 47 Staining, method of, 13 Starch, 98 Action of saliva on, 98 Action of pancreatic juice on, 101 Staining fluids, 10-13 Ammonia molybdate, 12, 112 Anilin dyes, 12, 112 Carmine, 11, 112 Beale's, 11, 112 Golding Bird's, 11, 112 Gold chloride, 13, 112 Hxmatozyliu, alcoholic solu- tion, 11 Hsematoxylin, aqueous solu- tion, 10, 112 Osmic acid, 6, 112 Picrocarmin, 11, 112 Silver nitrate, 13, 112 Stearate of glycerin, 100 Stokes' fluid, 97 note Stomach, structure of, 49 Stratum comeum, 67 lucidum, 57 Striped muscle, 35 Stroma of ovary, 67 Sublingual gland, 45 Sublobular veins, 54 Submaxillary gland, 45 Substantia gelatinosa cinerea, 40 Sugar, tests for, 92, 99, 103 Suprarenal bodies, 84 Sweat glands, 57 Sympathetic nerves, 38 T. Taotild corpuscles, 57 Tannic acid, effect of on blood, 20 Taste buds, 45 Taurocholic acid, 101 Preparation of, 109 Teazing, method of, 10' Tectorial membrane, 76 I Teeth, structure of, 77 times of eruption, 78 development of, 110 Tendon ceUs, 25 i Tests for albumins, 87 Acid albumin^ 91 Alkali albumm, 91 BUe acids, 101 Bile pigment, 101 Blood, 20, 97, 103 Casein, 91, 92, 93 Diabetic urine, 103 Bgg albumin, 89 Fat, 92, 100 Fibrin, 96 Fibrinogen, 95 Fibrinoplastin, 95 Gelatin, 97 Globulin, 95 Glycogen, 99 Grape sugar ffl'ehling's),99,103 Fermeutation,103 Moore's, 103 TrDmmer's, 103 Milk sugar, 92, 99 Myosin, 95 Mucin, 98 Otsalates, 103, 104 Paraglobulin, 95 Peptones, 96 Phosphates, 103, 104 Proteids, 87 Pus, 104 Seralbumin, 89 Starch, 98 Urates, 103, 104 Urea, 102 Uric acid, 102, 104 Testes, structure of, 65 Thoracic duct, 69 Thymus gland, 83 Thyroid gland, 83 Tongue, structure of, 45 Tonsils, structure of, 47 Tooth pulp, 78 papilla, 110 sac, 110 124 INDEX. Trachea, Btrnctnre of, 29, 55 Tiactus intermedio lateralis, 39 Transitional epithelium, 22, 63 Tubuli seminiferi, 65 Tunica adventitia, 43 Tunica albuginea, 65 Tunica granulosa, 67 yasculosa, 67 Tyrosin, 101 Preparation of, 109 V. TJmstriped muscle, 36 Urates, test for, 103, 104 Urea, 101 Nitrate, 102 Oxalate, 102 Quantitative analysis of, 102 Ureter, structure of, 63 Uric acid, 102, 104 Tests for, 102, 104 Urinary calculi, 104 Urinary deposits, analysis of, 104 Urinary organs, 61-63 Urine, healthy, 102 morbid, 102-104 Albumin, 102 Bile, 102 Blood, 103 Mucus, 102 Oxalates, 103 Phosphates, 103 Pus, 104 Sugar, 103 Urates, 103, 104 Uric acid, 102 Uterus, 67 V. Valentin's knife, 10 Valvulse conniTentes, 51 Vas deferens, structure of, 64 Yasa efferentia of testes, 65 Vasa recta : Kidney, 62 Testis, 65 Veins, structure of, 43 Vesicular column, 39 VesiculsB seminales, 65 Villi intestini, 51 Vitellin, 96 Vitelline membrane, 67 Vitellus, 67 Vitreous humour, 27 Voluntary muscle, 35 W. 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