DUPLICATE HX00032760 331 ass , cork; 0, spores oi mildew; M, mycelium or threads oi mildew; Mc, micrococci; B, bac- teria; Li, leptothrix filameuts (50U diameters). directions for the examination of starch-granules, air-bubbles, linen, cotton, and woollen fibres, and the usual constituents of the dust of a room, into the first practical lesson. 6 THE ESSENTIALS OF HISTOLOGY 1. Examination of starch-granules. Gently scrape the cut surface of a potato with the point of a knife : shake the starch-granules so obtained into a drop of water upon a clean slide and apply a cover-glass. With the low power the starch-granules look like dark specks differing considerably in size ; under the high power they are clear, flat, ovoid particles (fig. 3, St), with a sharp outline when exactly focussed. Notice the change in appearance of the outline as the microscope is focussed up or down. On close examination fine concentric lines are to be seen in the granules arranged around a minute spot which is generally placed eccentrically near the smaller end of the granule. Sketch two or three starch-granules. Notice the appearance of air-bubbles in the water. If comparatively large they are clear in the middle, with a broad dark border due to refraction of the light ; if small they may look entirely dark. 2. Examine fibres of linen and of cotton in water, using a high power. Compare the well-defined, relatively coarse, striated, and slightly twisted linen- with the longer, finer, and more twisted cotton-fibres. Sketch one of each kind. 3. Mount two or three hairs from the head in water and look at them, first with the low, then with the high power. Examine also some fibres from any woollen material and compare them with the hairs. They have the same structure, although the wool is finer and is curled ; its structure may be partly obscured by the dye. Draw one or two woollen fibres. 4. Examine some dust of the room in water with a high power. In addition to numerous groups of black particles of carbon (soot) there will probably be seen fibres of linen, cotton, or wool, and shed epitheliurn-cells derived from the epidermis. 5. Prepare a scale to serve for measuring objects under the microscope. To do this put a stage-micrometer (which is a glass slide ruled in the centre, with the lines ^ and — millimeter apart) under the microscope in such a manner that the lines run frorn left to right (the microscope must not be inclined). Focus them exactly. Put a piece of white card on the table at the right of the microscope. Look through the instrument with the left eye, keeping the right eye open. The lines of the micrometer will appear projected upon the paper. Mark their apparent distance with pencil upon the card, and after- wards make a scale of lines in ink the same interval apart. A magnified repre- sentation is thus obtained of the micrometer scale. Mark upon it the number of the eye-piece and of the objective, and the length of the microscope tube. This scale-card will serve for the measurement of any object without the further use of the micrometer. To measure an object, place the scale-card upon the table to the right of the microscope and view the object with the left eye, keeping the right eye open. The object appears projected upon the scale, and its size in ~ or ~ of a millimeter can be read off. It is important that the same objective and eye-piece should be employed as were used in making the scale, and that the microscope tube should be of the same length. LESSON II. STUDY OF THE HUMAN BLOOD -CORPUSCLES. 1. Having cleaned a slide and cover-glass, prick the finger and mount a small drop of blood quickly, so that it has time neither to dry nor to coagulate. Examine it at once with the high power. Note (a) the coloured corpuscles, mostlj- in rouleaux and clumps, but some lying apart seen flat or in profile ; (6) the colourless corpuscles, easily made out if the cover-glass is touched by a needle, on account of their tendency to stick to the glass, whilst the coloured corpuscles are driven past by the cur- rents set up ; (c) in the clear spaces, fibrin filaments and elementary particles or blood-tablets. Sketch a roll of coloured corpuscles and one or two colourless corpuscles. Count the number of colourless corpuscles in a field of the microscope. 2. To be made like 1, but the drop of blood is to be mixed upon the slide with an equal amount of 0"6 per cent, salt solution, so that the red corpuscles tend to be less massed together, and their peculiar shape is better displayed. Sketch a red corpuscle seen on the flat and another in profile (or optical section). Also a crenated corpuscle. Measure ten red corpuscles, and from the results ascertain the average diameter of a corpuscle. 3. Make a preparation of blood as in § 1 and put it on one side to coagu- late. After fifteen minutes allow a drop of a solution of borax-carmine ' to run under the cover-glass. This decolorises the red corpuscles, but stains the nuclei of the white corpuscles and brings the network of fibrin filaments and the elementary particles clearly into view (fig. 7). After a drop of gly- cerine has been allowed to diffuse into the fluid the cover-glass may be cemented with gold-size and the preparation labelled and kept. 4. Enumeration of the blood-corpuscles. This is readily effected by the hemacytometer of Gowers. This instrument consists of a glass slide (tig. 4, c), the centre of which is ruled into -^ millimeter squares and surrounded by a glass ring \ mm. thick. It is provided with measuring pipettes (a and b), a vessel (d) for mixing the blood with a saline solution (sulphate of soda of sp. gr. 1015), glass stirrer (e) and guarded needle (f). ' The mode of proceeding is extremely simple. 995 cubic millimeters of the saline solution are placed in the mixing jar; 5 cubic millimeters of blood are then drawn from a puncture in the finger and blown into the solution. The two fluids are well mixed by the Btirrer and a small drop of this dilution is placed in the centre of the cell, the cover-glass gently laid on (so as to touch the drop, which thus forms a layer \ nun. thick between the slide and cover- glass) and pressed down by two brass springs. In a lew minutes the cor- puscles have sunk to the bottom of the layer of fluid and rest on the squares. The Dumber in ten Bqnares is then counted, and this, multiplied by 10,000, gives the number in a cubic millimeter of blood.' 1 See Appendix. THE ESSENTIALS OF HISTOLOGY Fig. 4. — Hemacytometer of Gowers. o Fig. 5. — Human blood as seen on the warm stale. (Magnified about 1,200 diameters.) r, r, single red corpuscles seen lying flat ; /'. /•', red cor- puscles on their edge and viewed in profile ; >■". red corpuscles arranged in rouleaux ; c, c, crenate red cor- puscles; p, a finely granular pale corpuscle; g, a coarsely granular pale corpuscle. Both have two or three distinct vacuoles, and were undergoing changes of shape- at the moment of observation ; in in diameter. They are far fewer, numbering not more than ten thousand in a cubic millimeter. Moreover they are specifically lighter, and tend to come to the surface of the prepara- tion. If examined soon after the blood is drawn, they are usually spheroidal in shape, but they soon become irregular (fig. 5, p, g), and their outline continually alters, owing to the amoeba-like changes of form to which they are subject. Some of the colourless corpuscles are very pale and finely granular, FlG - ?•— Fibris-filaments and blood- • L J & TABLETS. others contain coarser and more , na *„„v ~* «v™„ -i ™„ ,«„ i • A. network of fibrin, shown after waslnnp away distinct granules in their protO- the corpuscles from a preparation of bl Ittaat , . L has been allowed to clot ; many of the fil plasm. lhe protoplasm may also radiate from small clumps of bl 1-1 i. • , _i_____ i B (from Osier), blood-corpuscles and elei Contain Clear spaces or vacuoles, tary particles or blood-tablets, within a small and a reticular structure is described vem> in it by some histologists. Each pale corpuscle has one or more nuclei, which are difficult to see without the aid of reagents. In the clear fluid in which the corpuscles are suspended, a network of fine straight intercrossing filaments (fibrin) soon makes its ap- pearance (fig. 7). There are also to be seen a certain number of 1 The following list gives the diameter in parts of a millimeter of the red blood- oorpusclea of some of the common domestic animals : — Dog, OOUTo ; rabbit, U0009 ; cat, 0-0005 ; sheep, 0-UOoU ; goat, 00U41. 10 THE ESSENTIALS OF HISTOLOGY minute round colourless discoid particles, either separate or collected into groups or masses, which may be of considerable size. These are the elementary particles or blood-tablets. Their meaning is not known. Fatty particles may also occur in the plasma. Development of blood-corpuscles. — In the embryo, the first-formed coloured blood-corpuscles are amoeboid nucleated cells, the protoplasm Fig. 8. — Development of blood-vessels and blood-corpuscles in the vascolar area of the guinea-pig. hi, blood-corpuscles becoming free in the interior of a nucleated protoplasmic mass. of which contains haemoglobin. These embryonic blood-corpuscles are developed within cells of the mesoderm, which unite with one another so as to form a protoplasmic network (fig. 8). The nuclei then multiply, and around some of them there occurs an aggregation of coloured protoplasm. Next the branched cells become hollowed Fig. 9. — Blood-corpuscles developing within connective-tissue cells. h, a cell containing diffused haemoglobin ; h', globular masses of coloured substance in the protoplasm, within which also are numerous vacuoles ; h", a cell filled with coloured globules. out by an accumulation of fluid in their protoplasm so as to form a network of blood-vessels, and then the coloured nucleated portions of protoplasm are set free within them as the embryonic blood- corpuscles (fig. 8, bl). DEVELOPMENT OF THE BLOOD-CORPUSCLES 11 In later embryonic life, and after birth, nucleated coloured cor- puscles are no longer present in mammalian blood, but are replaced by the usual discoid corpuscles. These are formed within certain cells of the connective tissue, a portion of the protoplasm of the cell becom- ing coloured by haemoglobin, and separated into globular particles (fig. 9, h, h', h"), which are gradually moulded into disk-shaped red corpuscles. In the meantime the cells become hollowed out, and join with similar neighbouring cells to form blood-vessels (fig. 10, a, b, c). The process is therefore the same as before, except that the cell-nuclei do not participate in it. Fig. 10. — Further development of blood-corpuscles in connective-tissue cells, and transformation of the latter into capillary blood-vessels. a, an elongated cell with a cavity in its protoplasm occupied by fluid and by blood-corpus- cles mostly globular; b, a hollow cell the nucleus of which has multiplied. The new nuclei are arranged around the wall of the cavity, the corpuscles in which have now become discoid; c shows the mode of union of a ' haemapoietic ' cell, which in this in- stance contains only one corpuscle, with the prolongation (6/) of a previously existing vessel, a, and c, from the new-born rat ; 6, from a foetal sheep. Although no nucleated coloured corpuscles are to be seen in the blood in post-embryonic life, they continue to be found in the marrow of the bones (see Lesson XIII.), and it is thought probable that the red disks may be formed in some way from these. Others have sup- posed that the red disks are derived from the white corpuscles of the blood and lymph, and others again that they are developed from the blood-tablets ; but the evidence in favour of these views is insufficient. The white blood -corpuscles and hpnph-corpuscles occur originally as free unaltered embryonic cells, which have found their way into the vessels from the circumjacent tissues. Later they become formed in lymphatic glands and other organs composed of lymphoid tissue, and pass from these directly into the lymphatics and so into the blood. 12 THE ESSENTIALS OF HISTOLOGY LESSON III. ACTION OF REAGENTS UPON THE HUMAN BLOOD- CORPUSCLES. 1. Make a preparation of blood as in Lesson II. 1, and apply a drop of water at one edge of the cover-glass. Examine at a place where the two fluids are becoming mixed. Notice particularly the first effect of water upon both red and white corpuscles, as well as the ultimate action. Sketch both kinds of corpuscles under the action of water. 2. Eepeat on another preparation, using very dilute alkali (0*2 per cent, potash in salt solution) instead of water. Notice the complete solution first of the white and then of the coloured corpuscles as the alkali reaches them. 3. Eepeat on another preparation, using dilute acetic acid (1 per cent.). Observe that the effect of the acid upon the coloured corpuscles is similar to that of water, but that it has a different action upon the colourless corpuscles. Sketch two or three of the latter after the action is completed. 4. Make a preparation of blood mixed with salt solution as in Lesson II. 2, and investigate the action of tannic acid (2 per cent, solution) hi the same way. Sketch two or three coloured corpuscles after the action is complete. The action of reagents upon the human red blood-corpuscles shows that, although to all appearance homogeneous, they in reality consist of an intimate intermixture of the colour - a, h e d e ing matter or haemoglobin with certain ^ £} ^ ^ other substances (globulin, lecithin, chfe- ■ lesterin), which are left as the colourless lv stroma, on dissolving out the ha?ino- ^•%^t y kJI globin, or on causing its discharge by any means from the corpuscle. This 11# separation of the haemoglobin from the a-e, successive effects of water upon a l^fxji /.cii red corpuscle ;/, effect of solution of stroma can be effected by water (fig. 11, salt; y, effect of tannic acid. a _ e) an( J a l so ty. d&ute acids, by the action of heat (60° C.)» the freezing and thawing of blood, the vapour of chloroform, and the passage of electric shocks through blood. 1 ' In the blood of some animals crystals of haemoglobin readily form after its separation by any of these means from the red corpuscles. These crys- tals are rhombic prisms in most animals, but tetrahedra in the guinea-pig, and hexagonal plates in the squirrel. They are most appropriately studied along with the chemical and physical properties of blood, and are therefore omitted here. The same remark applies to the minute dark-brown rhombic crystals (hczmiri), which are formed when dried blood is heated with glacial acetic acid, and to the reddish-yellow crystals of licematoidin, which are found in old blood extravasations. ACTION OF REAGENTS UPON HUMAN BLOOD 13 The mixing of human blood with the blood or serum of various animals also has a similar action, probably owing to differences of density or alkalinity. Tannic acid produces a peculiar effect (fig. 11, g) ; the haemoglobin is discharged from the stroma, but is immediately altered and precipitated, remaining adherent to the stroma in the form of a round or irregular globule of a brownish tinge (haematin). The structure of the colourless corpuscles is also brought out by the action of these reagents. As the water reaches them their amoe- boid movements cease ; they become swollen out into a globular form by imbibition of fluid (fig. 12, i), and the granules within the proto- Fig. 12. 1, first effect of the action of water upon a white blood-corpuscle ; 2, 3, white corpuscles treated with dilute acetic acid ; n, nucleus. plasm can be seen to be in active Brownian motion. Their nuclei also become clear and globular, and are more conspicuous than before. With the further action of the water, the corpuscle bursts and the granules are set free. Acids have an entirely different action upon the white corpuscles. Their nuclei become somewhat shrunken and very distinct ifig. 12, •2 and 3i, and a granular precipitate is formed in the protoplasm around the nucleus. At the same time, a part of the protoplasm generally swells out so as to form a clear bleb-like expansion (an appearance which often accompanies the death of the corpuscle from other causes). 14 THE ESSENTIALS OF HISTOLOGY LESSON IV. STUDY OF THE BLOOD-CORPUSCLES OF AMPHIBIA. 1. Mount a drop of newt's blood obtained from tbe cut end of the tail. Examine with the high power. Notice the shape of the coloured corpuscles, both when seen flat and edgeways, and the nucleus within each. Measure ten corpuscles, and from the results obtain the average dimen- sions of the newt's blood-corpuscle. Notice also the colourless corpuscles, smaller than the red, but consider- ably larger than the pale corpuscles of human blood, although otherwise re- sembling these. Sketch two or three red corpuscles and as many white. Be careful not to mistake the liberated nuclei of crushed red corpuscles for pale corpuscles. Enormous cells and nuclei belonging to the cutaneous glands as well as the granular secretion of those glands may be present in this preparation. 2. Apply a drop of water to the edge of the cover-glass of the same pre- paration and notice its action upon the corpuscles. Sketch two or three corpuscles altered by the action of the water. 3. Mount another drop of blood, and apply dilute acetic acid (1 per cent.) instead of water at the edge of the cover-glass. Make sketches showing the effect of the acid upon both red and white corpuscles. 4. Examine the corpuscles of newt's blood which has been allowed to flow into boracic acid solution (2 per cent.). Notice the effect produced upon the coloured corpuscles. Sketch one or two. The coloured blood-corpuscles of amphibia ( fig. 13), as well as of most vertebrates below mammals, are biconvex elliptical disks, considerably larger than the biconcave circular disks of mammals. 1 In addition to the coloured body of the corpuscle, which consists, as in mammals, of haemoglobin and stroma, there is a colourless nucleus, also of an ellip- tical shape, but easily becoming globular, especially if liberated by any means from the corpuscle. The nucleus resembles that of other cells in structure, being bounded by a membrane, and having a network of filaments traversing its interior (fig. 14). It is not very distinct in the unaltered corpuscle, but is brought clearly into view by the action 1 The following are the dimensions in parts of a millimeter of some of the corpuscles of oviparous vertebrates : — Long diameter Short diameter Pigeon . 0-0147 0-0065 Frog . . 0-0223 00157 Newt . . 0-0293 0-0195 Proteus . 0-058 0-035 Amphiuma . 0-077 0-04(3 STUDY OF THE BLOOD-CORPUSCLES OF AMPHD3L4. 15 of reagents, especially acetic acid. The action of reagents upon the red corpuscle of amphibia is otherwise similar to that produced upon the mammalian corpuscle, water and acetic acid causing it to swell into a globular form and then to become decolorised ; solution of salt causing a shrinking of the corpuscle, and so on. Boracic acid acts like tannic acid in causing the haemoglobin to be withdrawn from the stroma ; but it becomes partially or wholly collected around the nucleus, which may then be extruded from the corpuscle. Fig. 13. — Frog's Blood. (Ranvier.) a, red corpuscle seen on the flat ; r, vacuoles in a cor- puscle ; b, c, red corpuscles in profile; n, pale cor- puscle at rest ; m, pale corpuscle, exhibiting amoeboid movements ; p, coloured fusiform corpuscle. Fig. 14. — Coloured corpuscle of sa- lamander, show- ing intranuclear network. (Flem- ming.) The colourless corpuscles (fig. 13, k, m, n), although larger, are very similar to those of mammals. Like them, they are of two kinds — either wholly pale or enclosing a number of dark granules. They vary much in size and in the activity of their amoeboid movements. They may have one or several nuclei. Reagents have the same effect upon them as on those of mammals. 16 THE ESSENTIALS OF HISTOLOGY LESSON V. THE AMCEBOID PHENOMENA OF THE COLOURLESS BLOOD-CORP USCLES. 1. Make a preparation of blood froni the finger in the usual way. Draw a brush just moistened with oil around the edge of the cover-glass to check evaporation. Place the preparation upon a -warm stage,' and heat this to about the temperature of the ody (38° C). Bring a white corpuscle under observation with the high power, and watch the changes of shape which it undergoes. To become convinced of these alterations in form, make a series of outline sketches of the same corpuscle at intervals of a minute. The simplest form of ' warm stage ' is a thin copper plate of about the size of an ordinary slide, perforated in the centre and with a long tongue of the same metal projecting from the middle of one edge (fig. 15). The copper plate is firmly cemeuted with sealing-wax to a glass slide which rests upon the stage Fig. 15. — Simple warming apparatus, complete, shown in operation. of the microscope. The preparation, which should be made upon a rather thin slip of glass, is put on to the warm stage and pressed into contact with it by the brass clips. Heat is applied to the copper tongue by a small spirit- lamp flame, and a greater or less amount is conducted to the warm stage and the superjacent preparation according to the point to which the flame is AMCEBOID PHENOMENA OF COLOURLESS CORPUSCLES 17 applied. To ascertain that the right temperature is got and maintained, put two pieces of paraffin, one melting at 35° C. i ( J.3 3 F.) and another at 38° C. (100° F.), on the slide, one on either side of the preparation. The tempera- ture must be such that the first piece is melted and remains so whilst the second remains solid. 1 2. Mount a drop of newt's blood diluted with an equal amount of salt solution, and examine it in the same manner upon the copper stage ; the temperature must, however, be kept below 30° C. Observe the effect of heat in accelerating the amoeboid movements of the pale corpuscles. Sketch one at intervals of a minute (a) in the cold, (6) whilst warmed. 3. Examine some yeast which has been mixed with salt solution. Observe the yeast-cells or torulae, some of them budding. Sketch two or three. Now mix a little of the yeast and salt solution with a fresh drop of newt's blood, oiling the edge of the cover-glass as before. Endeavour to observe the inception of torulae by the white corpuscles. Sketch one or two corpuscles containing torulae. Milk-globules or particles of carbon or of vermilion may also be used for this experiment, but the process of inception is most readily observed with the yeast particles. 4. At the commencement of the lesson collect a drop of newt's blood into a fine capillary tube, seal the ends of the tube, and mount it in a drop of oil of cloves. Towards the end of the lesson examine it again to see white cor- puscles emigrating from the shrunken clot (see fig. 16). Fio. 10. — White cobpi scles oi i roc's blood migrated from shrunken CLOT within A CAPILLARY TUBE. 1 For exact work, an apparatus somewhat more complex than the above is re- quired. For description of such a one see A Course ofPractit al Histology, pp. 22, 2 I C 18 THE ESSENTIALS OF HISTOLOGY The amoeboid phenomena which are exhibited by the protoplasm of the colourless blood-corpuscles consist, in the first place, of spontaneous changes of form, which when active may also produce changes in place or actual locomotion (migration) of the corpuscle ; and, secondly, of a tendency which it presents to enwrap and take into its substance foreign particles with which it may come in contact, and particles thus incepted may then be conveyed by the corpuscle in its locomotory changes from one place to another. It is probable that particles of organic matter which are taken up by the pale corpuscles may undergo some slow process of intracellular digestion within their protoplasm. The processes of the granular corpuscles are generally quite clear at first, and the granules afterwards flow into them. The migration of the colourless corpuscles from the blood-vessels into the surrounding tissue, or from a blood-clot into the surrounding serum (fig. 16), is owing to these amoeboid properties. The conditions which are most favourable to this amoeboid activity of the white corpuscles are (1) the natural slightly alkaline medium, such as plasma, serum, or lymph, or, failing these, normal saline solution ; (2) the prevention of desiccation. Any increase of density of the medium produces a diminution of amoeboid activity, whilst, on the other hand, a slight decrease in its density has the opposite effect ; (3) a certain temperature. In warm-blooded animals the phenomena cease below about 10° C. When gradually warmed they become more and more active up to a certain point, the maximum being a few degrees above the natural temperature of the blood. Above this point they become spheroidal and their protoplasm is coagulated and killed. Acids at once kill the corpuscles and stop the movements. Narcotic gases and vapours, such as carbonic acid gas or chloroform vapour, also arrest the movement, but it recommences after a time if their action is discontinued. 19 LESSON VI. EPITHELIUM. 1. Mount a drop of saliva and examine first with a low, afterwards with the high power. Observe the nucleated epithelium-cells, some single, and others still adhering together by overlapping edges. Measure three or four, and also their nuclei. Sketch one or two on the flat and one edgeways. Notice the salivary corpuscles, which are like white blood-corpuscles swollen out by imbibition of water. 2. Put a small shred of human epidermis into a drop of strong caustic potash solution for one or two minutes. Then break it up hi water with needles, cover and examine. Observe the now isolated swollen cells. Measure some. 3. Study the arrangement of the cells in a section through some stratified epithelium, such as that of the mouth, skin, or cornea. The section may be prepared beforehand by the demonstrator ; it should be mounted in Canada balsam. 1 Notice the changes in shape of the cells as they are traced towards the free surface. Measure- the thickness of the epithelium. Count the number of layers of cells. 4. Study the minute structure of epithelium-cells and their nuclei, both at rest and dividing, hi the tail of the salamander-tadpole. 2 This preparation may also advantageously be prepared beforehand by the demonstrator. [The preparation is made as follows : The tail is placed in chromic acid solution (0 - l per cent.) for three days, then thoroughly washed for some hours in water to remove the excess of the acid, then placed in dilute hematoxylin solution for twenty-four hours, or in 1 p. c. safranin solution for a similar time. After having been again rinsed in water it is rapidly dehydrated in absolute alcohol, then transferred to spirits of turpentine, and finally mounted in Canada balsam.] Sketch an epithelium-cell with resting nucleus, and others with nuclei in different phases of karyornitosis. An Epithelium is a tissue composed entirely of cells separated by a very small amount of intercellular substance (cement substance i, and generally arranged so as to form a membrane covering either an ex- ternal or an internal free surface. The structure of epithelium-cells, and the changes which they undergo in cell-division, are best seen in the epidermis of the tail of the salamander-tadpole, in which the cells and nuclei are much larger than in mammals. 1 The methods of preparing sections are given in the Appendix. • If these tadpoles are not obtainable, the structure may be studied in the epidermis of the newt, prepared as recommended in Lesson VII. § 1 for the study of columnar epithelium, and also in sections stained with hematoxylin. c2 20 THE ESSENTIALS OF HISTOLOGY Structure of the cells. — Each cell consists of protoplasm containing a nucleus. The protoplasm may be either clear or granular, or it may- have a reticulated appearance. In some kinds of epithelium it is striated. The nucleus is a round or oval vesicle lying hi the proto- plasm. Usually there is only one, but there may be two or more in a cell. In the resting condition ( i.e. when not undergoing division | the nucleus is composed of a membrane enclosing a clear substance, which is traversed by a network of filaments (fig. 17, a). There may be one Fig. 17. — Epithelium-cells of salamander larva in different phases ok division. or more globular enlargements [nucleoli] on this network. The nucleus is stained more easily by dyes than the protoplasm ; this staining affects chiefly the nucleoli, nuclear filaments, and membrane. Division of the cells. — The division of a cell is preceded by the division of its nucleus. This, in dividing, passes through a series of remarkable changes (fig. 17), which may thus be briefly summarised: — 1. The network of filaments of the resting nucleus becomes trans- EPITHELIUM 21 formed into a sort of skein, formed apparently of one long convoluted filament ; the nuclear membrane and the nucleoli disappear or are merged into the skein (fig. 17, b, c, d). 2. The skein becomes arranged in the form of a rosette, the fila- ments looping in and out, to and from the centre (e). 3. The outer loops of the rosette separate, so that the filament breaks into a number of V-shaped fibres arranged like a star [aster, f, g, h.) 4. The V-shaped fibres separate into two groups, the ends of which for a time are interlocked (i, j, k). 5. The two groups pass to the opposite poles of the now elongated nucleus and form a star-shaped figure (Z) at each pole (dyaster). Each of the stars represents a daughter nucleus. 6. 7, 8. Each star of the dyaster goes through the same changes as the original nucleus, but in the reverse order — viz. rosette (mi, skein On, and network (o, p, q) ; passing finally into the condition of a typi- cal resting nucleus. The protoplasm of the cell divides soon after the formation of the dyaster (m). Sometimes fine lines maybe seen in the protoplasm, during the process of division, radiating from the poles of the nucleus, and others uniting the two daughter nuclei. Classification of epithelia. — Epithelia are classified according to the shape and arrangement of the component cells. Thus we speak of scaly or pavement, cubical, columnar, polyhedral, and spheroidal epithelium. All these are simple epithelia, with the cells only one layer deep. If forming several superposed layers, the epithelium is said to be stratified, and then the shape of the cells differs in the dif- ferent layers. Where there are only three or four layers in a stratified epithelium, it is termed transitional. . Stratified Epithelium covers the anterior surface of the cornea, lines the mouth, pharynx (lower part), and gullet, and forms the epi- dermis which covers the skin. In the female it lines the vagina and ~?*l Fig. 18. — Section of thk stratified epithelium covering the front ok THE CORNEA OF Till. EYE. c, lowermost columnar cells ; />, polygonal cells above these ; fl, flattened cells near ti. part of the uterus. The cells nearest the surface are always flat and scale-like (fig. 18, fl ; fig. 19), whereas the deeper cells are nioie 29 THE ESSENTIALS OF HISTOLOGY rounded or polyhedral, and those of the deepest layer generally some- what columnar in shape (fig. 18, c). Moreover, the deeper cells are soft and protoplasmic, and are separated from one another by a system of intercellular channels, which are bridged across by numerous pro- cesses passing from cell to cell. The deeper cells multiply by division, the newly formed cells tending as they enlarge to push those external to them nearer to the surface, from which they are eventually thrown off. As they approach the surface they become hard and horny, and in the case of the epidermis lose entirely their cellular appearance, which can, however, be in a measure restored by the action of potash (§ 2). The cast-off super- ficial cells of the stratified epithelium of the mouth, which are seen in abundance in the saliva (§ 1), are less altered, and the remains of a nucleus is still visible in them. Fig. 19. — Epithelium-scales from the Fig. 20. — Pavemext-efithelum from inside of the mouth. (Magnified 260 A serous membrane. (Magnified 410 diameters.) diameters. ) a, cell ; b, nucleus ; c, nucleoli. Simple scaly or pavement epithelium is found in the saccules of the lungs, in those of the mammary gland when inactive, in the kidney (in the tubes of Henle), and also lining the cavities of serous mem- branes (fig. 20), and the heart, blood-vessels, and lymphatics. When occurring on internal surfaces, such as those of the serous membranes, blood-vessels, and lymphatics, it is often spoken of as endothelium. Polyhedral or spheroidal epithelium is characteristic of many secreting glands ; columnar and ciliated epithelium are for the most part found covering the inner surface of mucous membranes, which are membranes lining passages in communication with the exterior, such as the alimentary canal and the respiratory and generative passages. The detailed study of most of these may be reserved until the organs in which they occur are respectively dealt with. The hairs and nails and the enamel of the teeth are modified epithelial tissues. 23 LESSON VII. COLUMN AE AXD CILIATED EPITHELIUM, AXD TRANSITION A L E PIT HE L I UM. 1. Take a piece of rabbit's intestine which has been two days in chromic acid solution (1 part chromic acid to 2.000 normal salt solution). Scrape the inner surface with a scalpel, break up the scrapings in a chop of water on a slide. Add a small piece of hair to avoid crushing, and cover the preparation. Sketch one or two columnar cells and also a row of cells. Measure two or three cells and their nuclei. To keep this preparation, add a drop of dilute haernatoxylin (1 drop of the ordinary solution to half a watch-glass-ful of distilled water) at one edge of the cover-glass. When the hematoxylin has passed in and has stained the cell- nuclei, place a drop of glycerine at the same edge, and allow it slowly to diffuse under the cover-glass. Cement this another day. 1 2. Break up in glycerine a shred of epithelium from a piece of frog's intestine that has been treated with osrnic acid, and has subsequently macerated in water for a few days. The cells easily separate on tapping the cover-glass. They are larger than those of the rabbit and exhibit certain points of structure better. Measure and sketch one or two cells. The cover-glass may be at once fixed by gold size. 3. Prepare the ciliated epithelium from a trachea that has been in bichromate of potash solution (£per cent.) for two days, in the same way as in § 1. Measure in one or two of the cells (a) the length of the cell. (6 the length of the cilia, [c) the size of the nucleus. Sketch two or three cells. This preparation is to be stained and preserved as in § 1. 4. Make a similar teased preparation of the epithelium of the urinary bladder. Observe the large flat superficial cells, and the pear-shaped cells of the second layer. Measure and sketch one or two of each kind. Stain and preserve as in §§ 1 and 3. Columnar epithelium. — The cells of a columnar epithelium (fig. 21 ) are prismatic columns, which are set closely side by side, so that when seen from the surface a mosaic appearance is produced. They often taper somewhat towards their attached end, which is generally trun- cated, and set upon a basement membrane. Their free surface is covered by a thick striated border (fig. 22, str), which may some- times become detached in teased preparations. The protoplasm of the cell is highly vacuolated or reticular, and fine longitudinal stria? may be seen in it, which appear continuous with the stria3 of th* 1 Gentian-violet solution (see Appendix) maybe employed instead of ha-ma toxylin. 24 THE ESSENTIALS OF HISTOLOGY free border. The nucleus (ri) is oval and reticular. The lateral borders of the cells are often somewhat irregular or jagged, the result of the pressure of amoeboid lymph-cells, which are generally found between the columnar cells, at least in the intestine. After a Fig. 21. A row of columnar cells from the intestine of the rabbit. Smaller cells are seen between the epithelium-cells, probably of the nature of white blood or lymph corpuscles. meal containing much fat the cells may be filled with fat-globules, which become stained black in the osmic preparation. Some of the columnar cells contain mucigen, which may greatly distend the part of the cell nearest the striated border. When the tr,-s Fig. 22. — Columnar epithelium-cells of thi? rabbit's intestine. The cells have been isolated after maceration in very weak chromic acid. The cells are much vacuolated, and one of them has a fat-globule near its attached end; the striated border (sir) is well seen, and the bright disk separating it from the cell-protoplasm ; n, nucleus with intranuclear network ; a, a thinned-out wing-like projection of the cell which probably fitted between two adjacent cells. mucigen is extruded as mucus, this border is thrown off, and the cell takes the form of an open cup or chalice (goblet-cell, fig. 23). Columnar epithelium-cells are found lining the whole of the interior of the stomach and intestines : they are also present in the ducts of most glands, and sometimes also in their secreting saccules. The epi- thelium which covers the ovary also has a modified columnar shape, but cells having all the structural peculiarities indicated above are found only in the alimentary canal and in its diverticula. Ciliated epithelium.— The cells of a ciliated epithelium are also usually columnar in shape (fig. 24), but in place of the striated border the cell is surmounted by a bunch of fine tapering filaments which, COLUMNAR. CILIATED, AXD TRANSITIONAL EPITHELIUM 25 during life, move spontaneously to and fro, and serve to produce a current of fluid over the surface which they cover. The cilia are to be regarded as active prolongations of the cell- protoplasrn. The border upon which they are set is bright, and appears formed of little juxtaposed knobs, to each of which a cilium is attached. In the large ciliated cells which line the alimentary canal of some molluscs (fig. 25) the knob may be observed to be prolonged into the protoplasm of the cell as a fine varicose filament, termed the rootlet of the cilium. These filaments may represent the longitudinal striae often seen in the protoplasm of the columnar cell, the bunch of cilia being homologous with the striated border. The protoplasm and nucleus have a similar vacuolated or reticular structure in both kinds of cell. Goblet cells may also occur in ciliated epithelia. Fig. 23.— Goblet cell Fig. 24. — Columnar cili- ated EPITHELIUM-CELLS. Fig. 25. — Ciliated cell, from the intestine OF A Mdl. i Ciliated epithelium is found throughout the whole extent of the air-passages and their prolongations (but not the part of the nostrils supplied by the olfactory nerves, nor in the lower part of the pharynx) ; in the Fallopian tubes and the greater part of the uterus; in some of the efferent ducts of the testicle i where the cilia are much longer than 26 THE ESSENTIALS OF HISTOLOGY elsewhere in the body i ; in the ventricles of the brain, and the central canal of the spinal cord ; and in the convoluted tubules of the kidney. Transitional epithelium is a stratified epithelium consisting of only two or three layers of cells. It occurs in the urinary bladder, the ureter, and the pelvis of the kidney. The superficial cells (fig. 26, a) are large and flattened ; they often have two nuclei. On their Fig. 26. — Epithelial cells from the bladder of the rabbit. (Magnified 500 diameters.) a. large flattened cell from the superficial layer, with two nuclei and with strongly marked ridges and intervening depressions on its under surface ; b, pear-shaped cell of the second layer adapted to a depression on one of the superficial cells. under surface they exhibit depressions, into which fit the larger ends of pyriform cells, which form the next layer (fig. 2G, b). Between the tapered ends of the pyriform cells one or two layers of smaller polyhedral cells are found. 27 LESSON VIII. STUDY OF CILIA IN ACTION. 1. Mount in sea-water one ox- two bars of the gill of the marine rnnssel (fig. 27 . Study the action of the large cilia. Now place the preparation upon the copper warm stage Bee Lesson V.) and observe the effect of raising the temperature. lr lr Fig. 27. — Valve of mussel (mttilus edulis) showing lr, br. the expanded GILLS OB BRANCHLE, WHII II. OWING TO THE LITTLE BARS OF WHICH THEY ARE COMPOSED, PRESENT A STRIATED ASPEI 1. ml. mantle ; m, cut adductor ruiuole ; i, mass of viscera : the dark projection just above is the foot. Keep this preparation until the end of the lesson, by which time many of the cilia will have become languid. When this is the case pass a drop of dilute potash solution 1 1 part KHO to 1,000 of sea-water) under the cover-glass and observe the effect. 2. Cement with sealing-wax a piece of small glass tubing to a slide so that Fig. 28.— Moist chamber adapted fob passing a gas or vapour to a PREPARATION UNDER THE MICROSCOPE. one end of the tube comes nearly to the centre of the slide. On this put a ring of putty or modelling wax half an inch in diameter so as to include the 28 THE ESSENTIALS OF HISTOLOGY end of the tube, and make a deep notch in the ring opposite the tube. Place a small drop of water within the ring (fig. 28). Put a bar from the gill upon a cover-glass in the least possible quantity of sea-water; invert the cover-glass over the putty ring, and press it gently down. The preparation hangs in a moist chamber within which it can be studied through the cover-glass, and into which gases or vapours can be passed and their effects observed. Pass CO., through the chamber, and after observing the effect replace it by air (see fig. 29). Eepeat with chloroform vapour instead of C0 2 . The Movement of Cilia. — When in motion a cilium is bent quickly over in one direction with a lashing whip-like movement, immediately recovering itself. When vigorous the action is so rapid, and the rhythm so frequent, that it is impossible to follow the motion with the eye. All the cilia upon a ciliated surface are not in action at the same Fig. 29. — Method of subjecting a preparation to a stream of carbonic anhydride. 6, bottle containing marble and hydrochloric acid : V wash-bottle, connected by indiarubber tube, t, with the moist chamber, s. instant, but the movement travels in waves over the surface. If a cell is detached from the general surface, its cilia continue to act for a while, but at once cease if they are detached from the cell. The rhythm is slowed by cold, quickened by warmth, but heat beyond a certain point kills the cells. The movement will continue for some time in water deprived of oxygen. Both CO, gas and chloro- form vapour arrest the action, but it recommences on restoring air. Dilute alkaline solutions quicken the activity of cilia, or may even restore it shortly after it has ceased. 20 LESSON IX. THE CONNECTIVE TISSUES. AREOLAR AND ADIPOSE TISSUE. 1. Take a little of the subcutaneous tissue or of the intermuscular connective tissue of a rabbit or guinea-pig and spread it out with needles on a dry slide into a large thin film. Keep the centre moist by occasionally breathing on it, but allow the edges to dry to the slide. Before commencing put a drop of salt solution on a cover-glass, and now invert this over the film. Ex- amine with a high power. Sketch one or two bundles of white fibres and also one or two elastic fibres, distinguishable from the former by their sharp outline, isolated coiuse, and by then.' branching. Sketch also one or more connective-tissue corpuscles, if any such are visible in the clear inter- spaces. Look also for migratory cells (lymph-corpuscles). Next carefully remove the cover-glass and replace the salt solution by dilute acetic acid. Watch its effect in swelling the white fibres and bringing more elearlj- into view the elastic fibres and corpuscles. Look for constricted bundles of white fibres. 2. Make another film in the same way, but mount in dilute magenta solution ' instead of saline solution. The elastic fibres are deeply stained by the dye ; the cells are also well shown. When the staining is completed pass dilute glycerine under the cover-glass and cement this at once with gold size. 3. Prepare another film of the subcutaneous tissue, including a little adipose tissue. Mount in glycerine and water, coloured by magenta, with a piece of hah - under the cover-glass to keep this frorn pressing unduly upon the fat-cells. Cement at once with gold size. Examine first with a low and after- wards with a high power. The nucleus and envelope of the fat-cell are well brought out by the magenta, and if from a young animal, fat-cells will be found in process of formation. Measure and sketch two or three of the cells. 4. Spread out another large film of connective tissue, letting its edges dry to the slide. Place on its centre a large drop of nitrate of silver solution (1 per cent.). After ten minutes wash this away with distilled water, mount in Tarrant ', and expose to the sunlight until stained brown. Sketch the out- lines of two or three of the cell-spao , The connective tissues include areolar tissue, adipose tissue, clastic tissue, fibrous tissue, ret if or m and lymphoid tissue, cartilage and bone. All these tissues agree in certain microscopical and chemical charac- ter-. They, for the most part, have a large amount of intercellular substance in which fibres are developed, and these fibres are of two 1 See Appendix. 30 THE ESSENTIALS OF HISTOLOGY kinds — white and yellow or elastic. Moreover, there are many points of similarity between the cells which occur in these several tissues ; they are also developed from the same embryonic formation, and they tend to pass imperceptibly the one into the other. Besides this, their use is everywhere similar; they serve to connect and support the other tissues, performing thus a passive mechanical function. They may therefore be grouped together, although differing consider- ably in external characters. Of tbese connective tissues, however, there are three which are so intimately allied as to be naturally con- sidered together, being composed of exactly the same elements, although differing in the relative development of those elements ; these are the areolar, elastic, and fibrous tissues (adipose tissue may be looked upon as a special modification of areolar tissue). Areolar tissue being the commonest and, in one sense, the most typical, its structure may be considered first. Areolar tissue. — The areolar tissue presents to the naked eye an appearance of fine transparent threads and lamina? which intercross in every direction with one another, leaving intercommunicating meshes, or areolae, between them. When examined with the microscope, these threads and fibres are seen to be principally made up of wavy bundles of exquisitely fine transparent fibres {white fibres, fig. 30). The bun- dles run in different directions, and may branch and intercommuni- cate with one another ; but the individual fibres, although they pass from one bundle to another, never branch or join other fibres. The Fig. 31. — Ground substance of connective tissue stained by silver. (The cell-spaces are left white.) Fig. 30. — Bundles of the white fibres of areolar tissue partly unravelled. fibres are cemented together into the bundles by a clear substance containing mucin, and the same clear material forms also the basis or ground-substance of the tissue, in which the bundles themselves course, and in which also the corpuscles of the tissue lie embedded. This THE CONNECTIVE TISSUES 31 ground-substance between the bundles can with difficulty be seen in the fresh tissue on account of its extreme transparency ; but it can be brought to view by staining with nitrate of silver, as in § 4. The whole of the tissue is thereby stained of a brown colour, with the exception of the spaces which are occupied by the corpuscles (cell-spaces, fig. 31). Besides the white fibres of connective tissue here described, fibres of a different kind (fig. 32) may be made out in the preparations; Fig. 32. A. Elastic fibres of areolar tissue. From the subcutaneous tissue of the rabbit. B (from ToMt >. A white lmn~ connective-tissue cells. /, a cell with a few isolated fat-droplets in its protoplasm : /"', a cell with a single large and several minute drops ; /". fusion of two large drops ; g, granular or plasma cell, not yet exhibiting any fat-deposition ; c t, flat connective-tissue corpuscle ; c, c, network of capillaries. as these droplets increase in size they run together into a larger drop, which gradually fills the cell more and more, swelling it out so that the cell-protoplasm eventually appears merely as the envelope of the fat -vesicle. Fat is found most abundantly in subcutaneous areolar tissue, and under the serous membranes ; especially in some parts, as at the back of the peritoneum around the kidneys, under the epicardium, and in the mesentery and omentum. The marrow of the long bones is also principally composed of fat. 35 LESSON X. THE CONNECTIVE TISSUES (continued). ELASTIC TISSUE, FIBROUS TISSUE, SPECIAL VARIETIES, DEVELOPMENT OF CONNECTIVE TISSUE. 1. Tease out as finely as possible a small shred of elastic tissue (ligarnentum nucha? of the ox or liganienta subflava of man) in Farrant's solution 1 and cover the preparation. Note the large well-defined fibres constantly branching and uniting with one another. Look for transverse markings on the fibres. Measure three or four. Sketch a small part of the network. Note the existence of bundles of white fibres amongst the elastic fibres. 2. Mount in Farrant a thin transverse section of ligarnentum nucha? which has been hardened in 2 per cent, solution of bichromate of potash. Observe the grouping of the fibres and then angular shape. Sketch one or two groups. 3. Pinch off the end of the tail of a dead mouse or rat, draw out the long silk-like tendons and put them into saline solution. Take two of the longest threads and stretch them along a slide, letting the ends dry firmly to the slide but keeping the middle part moist. Put a piece of hair between them and cover in saline solution. Observe with a high power the fine wavy fibrillation of the tendon. Draw. Now run dilute acetic acid under the cover-glass, watch the tendons where they are becoming swollen by the acetic acid. Notice the oblong nucleated cells coming into view between the tendon bundles. Sketch three or four cells in a row. Lastly, lift the cover-glass, wash away the acid with distilled water, place a drop of hematoxylin solution on the tendons, and leave the preparation for fifteen minutes or more ; then wash away the logwood and mount the preparation in acidulated glycerine. Cement the cover-glass with gold size. 4. Immerse one or two other pieces of tendon in nitrate of silver solution (1 per cent.) for ten minutes, then wash them in distilled water, stretch them upon a slide, mount in Farrant, and expose to the sunlight. 5. Stain with magenta solution ' a thin section of a tendon which has been hardened in alcohol. Mount in dilute glycerine and cement the cover- glass at once. Sketch a portion of the section under a low power. Elastic tissue is a variety of connective tissue in which the elastic fibres preponderate. It is found most characteristically in the liga- rnentum nuclne of quadrupeds and the liganienta subflava of the vertebra, but the connective tissue of other parts may also have a con- 1 See Appendix. 36 THE ESSENTIALS OF HISTOLOGY siderable development of elastic fibres. It occurs also in an almost pure form in the walls of the air-tubes, and uniting the cartilages of the larynx. It also enters largely into the formation of the walls of the blood-vessels, especially the arteries. In the ligamentum nuchas the fibres are very large and angular (fig. 38) ; they often exhibit cross-markings or even transverse clefts. When dragged asunder, they break sharply across ; they constantly branch and unite, so as to form a close network. In transverse section they are seen to be separated into small groups (fig. 39) by intervening white bundles of connective tissue. f **L*% mm*? G> CD Fig. 39. — Cross-section of elastic fibres from the ligamentum nuch.e of the ox. Fig. 38. — Elastic fibres from the liga- mentum NUCH.E OF THE OX, SHOWING TRANSVERSE MARKINGS ON THE FIBRES. Elastic tissue does not always take the form of fibres, but may occur as membranes (as in the blood-vessels). Sometimes the fibres are very small, but their microscopical and chemical characters are always very well marked (see p. 31). Fibrous tissue is almost wholly made up of bundles of white fibres running in a determinate direction. These again are collected into larger bundles, which give the fibrous appearance to the tissue. The bundles are constantly uniting with one another in their course, although their component fibres remain perfectly distinct. The interspaces between the larger bundles are occupied by areolar tissue (fig. 40) in which the blood-vessels and lymphatics of the fibrous FIBROUS TISSUE ,6 37 '•■d Fig. 40. — Part of a large tendon* in transverse section. a. areolar sheath of the tendon, with the fibres for the most part running transversely, but with two or three longitudinal bundles, b ; '.lymphatic cleft in the >heath: immediately over it a blood-vessel is seen cut across, and on the other side of the figure a small artery iwn cut longitudinally ; <-. large septum of areolar tissue ; <', -mailer septum ; e, still smaller septum. The irregularly stellate bodies are the tendon cells in section. Fig. 41. — Tendon of house's tail, stained with logwood; showing chains OK CELLS BETWEEN THE TENDON-BUNDLES. (175 diameters.) Fig. 42. — Transverse section op tendon of house's tail, stained. ( 175 diameters.) The flattened processes of the tendon-cells appeal in section as lines, frequently coming off at right angles from the body of the cell. 38 THE ESSENTIALS OF HISTOLOGY tissue are conveyed. The interstices between the smallest bundles are occupied by rows of connective-tissue corpuscles (tendon-cells), which from being squeezed up between three or more bundles become flattened out in two or three directions. In transverse section the cells appear somewhat stellate (figs. 40, 42), but when seen on the flat they appear lamellar (fig. 41 1, and from this aspect their general shape is square or oblong. They lie, as before said, in rows between the tendon-bundles, and the nuclei of adjacent cells are placed opposite ^^AiUfe ^*^H^^SHK^|BP Fig. 43. — Eight cells from the same tendon* as represented in fig. 41. (425 diameters.) The nuclei, with their numerous nucleoli, are coloured by the logwood. The dark lines on the surface of the cells are the optical sections of lamellar extensions directed towards or a "vay from the observer. one another in pairs (fig. 43). The cell-spaces correspond hi general figure and arrangement to the cells which occupy them (fig. 44 1. Fig. 44. — Cell-spaces of tendon of house's tail, brought into view by treatment with nitrate of silver. (175 diameters.) Fibrous tissue forms the tendons and ligaments, and also certain membranes, such as the dura mater, the fibrous pericardium, the fascia? of the limbs, the fibrous covering of certain organs, &c. It is found wherever great strength combined with flexibility is concerned. It receives a few blood-vessels, disposed longitudinally for the most part, and contains many lymphatics. Tendons and ligaments also receive nerve-fibres, which, in some cases, end in small localised ramifications like the end-plates of muscle, while others terminate in end-bulbs or in simple Pacinian corpuscles. Retiform or reticular tissue is a variety of connective tissue in which the intercellular or ground substance has mostly disappeared or is replaced by fluid, very few or no fibres having been developed in it ; and these, when present, are enwrapped by the cells. Tbe tissue is composed almost entirely of the cells, which are ramified and united VARIETIES OF CONNECTIVE TISSUE 39 with one another into a network or sponge-work by their processes ; in some cases, the cell-nuclei have disappeared (as at b, fig. 45). Fig. 45. — Thin section from the cortical part of a lymphatic gland, magnified. A network of fine trabeculae formed by retiform tissue, from the meshes of which the lymph-corpuscles have been washed out, except at c, where they are left. Lymphoid or adenoid tissue is retiform tissue in which the meshes of the network are largely occupied by lymph-corpuscles. This is by far the most common condition of a retiform tissue, and is met with in the lymphatic glands and allied structures (see Lesson XXII. |, and also in the tissue of the alimentary mucous membrane, and hi some other situations. Basement membranes (membranes propria? i are homogeneous-look- ing membranes, which are found forming the surface-layers of con- nective-tissue expansions in many parts, especially where there is a covering of epithelium, as on mucous membranes, in secreting glands, and elsewhere. They are generally formed of flattened connective- tissue cells joined together to form a membrane ; but, in some cases, they are evidently formed not of cells, but of condensed ground- substance, and in others they are of an elastic nature. Jelly-like connective tissue, although occurring largely in the em- bryo, is found only in one situation in the adult — viz. forming the vitreous humour of the eye. It seems to be composed entirely of soft ground-substance, with cells scattered here and there through it, and with very few fibres, or none at all. These several varieties of con- nective tissue will be more fully described in connection with the organs where they occur. Development of connective tissue. Connective tissue is always developed in the mesoblast or mesoderm of the embryo. In those parts of this layer which are to form connective tissue, the embryonic cells become separated from one another by a muco-albuminous semi- fluid intercellular substance ( ground- substance), but the cells generally remain connected by their processes. The connective-tissue fibr -. 40 THE ESSENTIALS OF HISTOLOGY both white and elastic, are deposited in this ground-substance, the elastic substance usually in the form of granules (fig. -17, g), which ^ Fig. 46. — Jelly of Wharton*. r, ramified cells intercommuuicatiug by their branches : /. a row of lymph-cells ; *, fibres developing in the ground-substance. subsequently become connected together into elastic fibres or lamina?, as the case may be, the white fibres appearing at first in the form of very fine bundles, which afterwards become gradually larger ; so that in fibrous tissue the whole ground- substance is eventually pervaded by Fig. 47. — Development of elastic tissue by deposition of fine granules. g, fibres being formed of rows of 'elastin' granules ; ;/. flat platelike expansion of elastic substance formed by the fusion of 'elastin ' granules. them, and the cells of the tissue become squeezed up into the intervals between them. Before any considerable development of fibres has taken place, the embryonic connective tissue has a jelly-like appear- ance ; in this form it occurs in the umbilical cord, where it is known as the jelly of Wharton (fig. 46). 41 LESSON XI. THE CONNECTIVE TISSUES {continued). ARTICULAR CARTILAGE. 1. Cut two or three very thin tangential slices of the fresh cartilage of a joint, mount them in saline solution and examine with a high power. Observe care- fully the form and grouping of the cells. Look at the thin edge of the section for spaces from which the cells have dropped out. Measure two or three cells and their nuclei, and sketch one or two groups. Now replace the saline solution by water and set the preparation aside for a little while. On again examining it, many of the cartilage-cells will be found to have shrunk away from then containing capsules. 2. Make other sections of the cartilage (1) from near the middle. (2) from near the edge. Mount in magenta solution, and when stained add dilute glycerine and cement the cover-glass. In (2) look for branched cartilage-cells. Draw one or two. 3. Make vertical sections of articular cartilage from a bone which has been for several days in h per cent, chromic acid solution, and mount the sections in Farrant. Sketch the arrangement of the cells in the different layers. 4. Wash a fresh joint with distilled water ; drop 1 per cent, nitrate of silver solution over it; after ten minutes wash away the nitrate of silver and expose in water to the light. "When browned, cut thin sections from the surface and mount in Farrant. The cells and cell-spaces show white in the brown ground-substance. Draw. Cartilage or gristle is a translucent bluish-white tissue, firm, and at the same time elastic, and for the most part found in connection with bones of the skeleton, most of which are in the embryo at first represented entirely by cartilage. Two chief varieties of cartilage are distinguished. In the one, which is termed hyaline, the matrix or ground-substance is clear, and free from obvious fibres ; in the other, which is termed fibro-cartilagc, the matrix is everywhere pervaded by connective-tissue fibres. When these are of the white variety, the tissue is white fibro-cartilagc ; when they are elastic fibres, it is yellow tie tibro-cartilage. Hyaline cartilage occurs principally in two situations — namely (1) covering the ends of the bones in the joints, where it is known as articular cartilage; and (2i forming the rib-cartilages, where it is known as costal cartilage. It also forms the cartilages of the nose, the 42 THE ESSENTIALS OF HISTOLOGY external auditory meatus, the larynx, and the windpipe ; in these places it serves to maintain the shape and patency of the orifices and tubes. Articular cartilage. The cells of articular cartilage are mostly scattered in groups of two or four throughout the matrix (fig. 48). The latter is free from fibres, except at the extreme edge of the ■ ,,■■■■:■' :■<<&& .-'..%) Sf§§ a u Fig. 48. — Articular cartilage from head of metatarsal bone of man (OSMIC ACID PREPARATION). The CELL-BODIES ENTIRELY FILL THE SPACES rx the matrix. (340 diameters.) a, group of two cells ; b, group of four cells ; h. protoplasm of cell, with g, iaXty granules n, nucleus. cartilage, where the connective-tissue fibres from the synovial mem- brane extend into it ; and here also the cartilage-cells are often branched, and offer transitions to the branched connective-tissue cor- puscles of that membrane (transitional cartilage, fig. 49). By long maceration, however, some observers have obtained evidence of a fibrous structure even in the matrix of true hyaline cartilage. The matrix immediately around the cartilage-cells is often marked off from the rest by a concentric line or lines, this part being known as the capsule of the cell. The cells are bluntly angular in form, the sides opposite to one another in the groups being generally flattened. The protoplasm is very clear, but it may contain droplets of fat ; and with a high power fine interlacing filaments and granules have been observed in it (fig. 50 j. During life the protoplasm entirely fills the ARTICULAR CARTILAGE 43 cavity or cell- space which it occupies in the matrix ; but after death, and in consequence of the action of water and other agents, it tends to shrink away from the capsule. The nucleus is round, and shows the usual intranuclear network. 4" Fig. 49. — Border of articular cartilage showing Fig. 50. — A cartilage-cell TRANSITION OF CARTILAGE-CELLS INTO CONN ECTIVK- TI8SUE i ORPUSCLES OF SYNOVIAL MEMBRANE. FROM HEAD OF METATARSAL BONE, HUMAN. (About O-A0 diameters.) a, ordinary cartilage-cells ; b, b, with branching processes. IN THE LIVING STATE, FROM THE SALAMANDER. Highly magnified. a &E)l3< ■=; c OE» OH ^e. aeiE '- . — .• ** * "1 I 1 -• > § | ■ Fig. 51. — Vertical section ok articular cartilage covering the lower end of the tibia, human. (Magnified about 80 diameters.) a, cells and cell-groups Battened conformably with the surface: 6, cell -groups irregularly arranged; e, cell-groups disposed perpendicularly to the surface; d, layer of calcined cartilage ; e, bone. In vertical section (fig. 51) the deeper cell-groups (c) are seen to be arranged vertically to the surface, the more superficial ones (a) parallel to the surface ; whilst in an intermediate zone the groups are irregu- 44 THE ESSENTIALS OF HISTOLOGY larly disposed \b). In the deepest part of the cartilage, next the bone, there is often a deposition of calcareous salts in the matrix {calcified cartilage, d). The disposition of the cells of cartilage in groups of two, four, and so on, is apparently due to the fact that these groups have originated from the division of a single cell first into two. and these again into two, and so on (fig. 52). It would seem that the matrix is formed of _ ■ . ... . uJ | Ui,.liiu,»Jj.i u ,Uj,jAjJl|liiJ. "...,.„„., „ t Fig. 52. — Plan- of the multiplication of cells of ARTILAGE. A, cell in its capsule ; b, divided into two, each with a capsule ; c, primary capsule disap- peared, secondary capsules coherent with matrix; D, tertiary division; E, secondary capsuks disappeared, tertiary coherent with matrix. Fig. 53. — Division of a caktilage-cell. a-h. stases of division of a cell, as seen in the living cartilage of the salamander (the con- nection of the nuclear filaments could not be made out in the fresh condition >. a, b. stel- late phase ; c, d, commencing separation of the nuclear filaments : the further stages of separation are not represented ; e, filaments fully separated into two groups, and a septum beginning to be formed between them : f, septum completed, seen to be double and con- tinuous with capsules of daughter cells; g, h, further stages in the formation of the daughter nuclei. successive portions, which are deposited around each cartilage-cell as the so-called ' capsules, each newly formed portion soon blending in its turn witli the previously formed matrix, whilst a new capsule is formed within it. The division of the cartilage-cell, like that of other cells, is accompanied by a process of karyomitosis. 45 LESSON XII. THE CONNECTIVE TISSUES {continued). COSTAL CARTILAGE. FIBRO-CARTILAGE. 1. Make transverse and tangential sections of a rib-cartilage, stam them with ra, and mount in dilute glycerine, cementing at once. Sketch a part of a transverse section under a low power and a cell-group from one of the tangential sections under a high power. Notice especially the arrangement of tin- cells, somewhat concentric near the surface but radial near the centre. The costal cartil s t'ten ossified near the middle. •1. Make sections of the cartilage of the external ear. Mount in dilute glycerine faintly coloured with magenta. If from the ox. notice the very reticulating elastic fibres in the matrix. Notice also the isolated granules of elastin, and around the cartilage-cells the area of clear ground- substance. Draw a small portion of the section. 3. Mount a section of the epiglottis In the same way. network of much liner fibres. Notice the closer 4. Cut sections of white fibro-cartilage (intervertebral disk), and stain them with dilute magenta. Mount in dilute glycerine. Observe the wavy fibres in the matrix and the cartilage-cells lying in clear areas often con- centrically striated. Look for branched cartilage-cells. Sketch three or four cells and the adjoining fibrous matrix. Costal cartilage. — In the costal cartilages the matrix is not always so clear as in the matrix of the joints, for it often happens that fibres Fig. 54.— Si.i rios oi rib-cartilage, showing two cell-groups ra a SOMEWHAT FIBROU8-LOOKING MATRIX. become developed in it. The cells are generally larger and more an- gular than those of articular cartilage, and collected into larger groups 46 THE ESSENTIALS OF HISTOLOGY (fig. 54). Near the circumference, and under the perichondrium or fibrous covering of the cartilage, they are flattened and parallel to the surface, but in the deeper parts they have a more irregular or a radi- ated arrangement. They frequently contain fat. The cartilages of the larynx and windpipe and of the nose resemble on the whole the costal cartilages, but the study of them may be deferred until the organs where they occur are dealt with. Elastic or yellow fibro-cartilage occurs in only a few situations. These are, the cartilage of the external ear and that of the Eustachian tube, the epiglottis and cartilages of Santorini of the larynx, and in some animals, e.g. the ox, the upper third of the arytenoids. The matrix is everywhere pervaded with well-defined branching fibres, which unite with one another to form a close network (fig. 55). These Fig. 55. — Section of the elastic carti- lage ok the ear. (Highly magnified.) ■ Fig. 56. — Section of part of the car- tilage of the epiglottis. a, cartilage-cell in clear area ; b. granular- looking matrix near the middle of the carti- lage, the granular appearance being due partly to the fine reticulum of elastic fibres, partly to the presence of granules of elastic substance in the matrix ; c, clearer matrix with longer fibres. fibres resist the action of acetic acid, and are stained deeply by magenta ; they are evidently elastic fibres. In the ox they are very large, but smaller in man, especially in the cartilage of the epiglottis (fig. 56). They appear to be developed by the deposition of granules of elastin in the matrix, which at first he singly, but afterwards become joined to form the fibres. White fibro-cartilage is found wherever great strength combined with a certain amount of rigidity is required : thus we frequently find fibro-cartilage joining bones together, asm the case of the intervertebral disks and other symphyses. Fibro-cartilage is frequently employed to line grooves in which tendons run, and may also be found in the tendons themselves. It is also employed to deepen cup- shaped articular sur- faces ; and in the case of the interarticular cartilages, such as those of the knee and lower jaw, to allow greater freedom of movement whilst diminishing the liability to dislocation. Under the microscope FIBRO-CARTILAGE 47 white fibro-cartilage looks very like fibrous tissue, but its cells are car- tilage-, not tendon-, cells (fig. 57). They are rounded or bluntly angular Fig. . — White fibr<: :artilage FROM an intervertebral disk, human. (Highly magnified.) The concentric lines around the cells indicate the limits of deposit of successire capsules. One of the cells has a forked process which extendi beyond the hyaline area surrounding the cell, amongst the fibres of the genera! matrix. and surrounded by a concentrically striated area of clear cartilage-* matrix. In some parts of the intervertebral disk many of the cells are branched, and may be looked upon as transitional forms to connective- tissue corpuscles. 48 THE ESSENTIALS OF HISTOLOGY LESSON XIII. BONE AXD MARROW. 1. In thin sections of hard bone made by grinding, observe the Haversian canals, lamellae, lacunae, canaliculi, &c. Make a sketch hrst under a low and afterwards under a high power. 2. With fine forceps strip off a thin shred from a bone which has been decalcified in nitric acid and afterwards kept for some time in dilute alcohol. Mount the shred in water. Observe the fibrous structure of the lamellae. Look for perforating fibres or the holes from which they have been dragged out. Sketch a small piece of the thin edge of a lamella. 3. Stain with dilute magenta very thin sections of compact bone which has been decalcified hi chromic or picric acid, and mount in dilute glycerine, cementing at once. Look for fibres of Sharpey piercing the circumferential lamellae. The elastic perforating fibres are more darkly stained than the others. Notice the stained nuclei of the bone-corpuscles in the lacunae. In the thinnest parts of the sections try to make out the blood-vessels and other structures in the Haversian canals. 4. Mount in Canada balsam sections of marrow (from a long bone) stained with hematoxylin or borax-carmine.' Observe the fat- cells, the reticular tissue supporting them, the proper marrow-cells in this tissue, &c. 5. Tease in saline solution some of the red marrow from the rib of a recently killed animal. Observe and sketch the proper marrow-cells and look for myeloplaxes and nucleated coloured blood-corpuscles. If examined carefully, amceboid movements may be detected in the latter and in the marrow-cells. Bone is a connective tissue in which the ground- substance is im- pregnated with salts of lime, chiefly phosphate, these salts constituting about two-thirds of the weight of the bone. When bones are macerated this earthy matter prevents the putrefaction of the animal matter. When bones are calcined they lose one-third of their weight, owing to the destruction of the animal matter ; when steeped in acid the earthy salts are dissolved and only the animal matter is left. This, like areolar and fibrous tissue, is converted into gelatine by boiling. Bony tissue is either compact or cancellated. Compact bone is dense like ivory ; cancellated is spongy with obvious interstices. The outer layers of all bones are compact, and the inner part is generally cancellated, but the shaft of a long bone is almost entirely made up of 1 See Appendix. BONE 49 compact substance except' along the centre, which is hollow and filled with marrow. The interstices of cancellated bone are also occupied by marrow. Externally bones are covered except at the joints by a vascular fibrous membrane, the periosteum. True bone is always made up of lamella, and these again are com- posed of fine fibres lying in a calcified ground-substance. Between the lamellae are branched cells, the bone-corpuscles, which he in cell- spaces or lacuna. The ramified passages which contain the cell-pro- cesses are termed canaliculi. In cancellated bone the blood-vessels run in the interstices supported by the marrow. In compact bone they are contained in little canals — the Haversian canals — which everywhere pervade the bone. These canals are about O05 mm. i-J^ inch) in diameter, but some are smaller, others larger than this. Their general direction is longitudinal, i.e. parallel to the long axis of the bone, but they are constantly united by transversely and obliquely running passages. In a section across ■^ IISJW Fig. 58. — Trassverse se< nos op a bone (ulna). (Magnified 20 diameters.) The openings of the Haversian canals are seen encircled by concentric lamella?. Other lamella? run parallel with the surface l the >haft of a long bone they are seen as small rounded or irregular holes I fig. 58 i. When the section has been made by grinding, the holes get filled up with air and debris, and they then look black by "X) THE ESSENTIALS OF HISTOLOGY transmitted light, as do also the lacuna? and canaliculi (fig. 59). Most of the lamella? in compact bone are disposed concentrically around the Haversian canals ; they are known as the Haversian lamellae, and with Fig. 59. — Transverse section* of compact tissue (of humerus). (Magnified about 150 diameters.) Three of the Haversian canals are seen, with their concentric rings; also the lacunae, with the canaliculi exteuding from theru across the direction of the lauiellre. The Haversian apertures had become filled with air and debris in grinding down the section, and therefore appear black in the figure, which represents the object as viewed with transmitted light. the included canal form what is known as a Haversian system. The lacuna? of a Haversian system communicate with one another and with the Haversian canal, but not as a rule with the lacuna? of other Haversian systems. The angular interstices between the Haversian systems are generally occupied by bony substance, which is fibrous but not distinctly lamellar. Besides the lamellae of the Haversian systems there is a certain thickness of bone at the surface, immediately under- neath the periosteum, which is composed of lamella? arranged parallel with the surface; these are the circumferential ox periosteal lamcllce (fig. 58, a). They are pierced here and there by canals for blood- vessels, which are proceeding from the periosteum to join the system of Haversian canals, and also by calcified bundles of white fibres and by elastic fibres which may also be prolonged from the periosteum. These are the perforating fibres of Sharp ey (fig. 60). The lamella? of bone are fibrous in structure. This may be seen in shreds torn off from the superficial layers of a decalcified bone (fig. 61). The fibres often cross one another in adjacent lamella?, and in the Haversian systems they run in some lamella? concentrically, in others parallel with the Haversian canal. In shreds of lamella? which have been peeled off from the surface the perforating fibres may some- times be seen projecting from the surface of the shred, having been BONE 51 Fig. 60. — Transverse section of decalcified human tibia, from near the surface of the shaft. h, ii. Haversian canals, with their systen brie lamellae ; in all the rest of the figure the lamella; are circumferential; s, ordinary perforating fibres of Sharpey ; e, e, elastic perforating fibres. Drawn under a power of about 15u diameters. ^ Fig. 61. — Lamells torn off from a decalcified human parietal rune at SOME DEPTH FROM nil -i Ki A( I . ■(, lamella 1 , showing decussating fibres; '>. 6, thicker part, where several lamella; are super- posed; r. c, perforating fibres: the fibrils which compose them are not shown in the figure. Apertures through w 1 . i > • 1 » perforating fibres had passed are seen, especially in the lower part, a, a, of the figure. Magnitude as seen under a power of 800, but not drawn to scale. E 2 52 THE ESSENTIALS OF HISTOLOGY torn out of the deeper lamellae (fig. 61 c, c). Where tendons or liga- ments are inserted into bone, their bundles of white fibres are prolonged into the bone as perforating fibres. The lacuna? are occupied by nucleated corpuscles, which send branches along the canaliculi. The Haversian canals contain one or two blood-capillaries and nervous filaments, besides a little connective tissue ; and the larger ones may also contain a few marrow-cells. There are also cleft-like lymphatic spaces running parallel with the vessels and connected by means of canaliculi with neighbouring lacunae in the osseous substance (fig. 62). Fig. 62. — Section of a Haversian canal, showing its contents. (Highly magnified.) a, small arterial capillary vessel ; r, large venous capillary : n, pale nerve-fibres cut across ; /, cleft-like lymphatic vessel : one of the cells forming its wall communicates by fine branches with the branches of a bone-corpuscle. The substance in which the vessels run is connective tissue with ramified cells ; its finely granular appearance is probably due to the cross-section of fine fibrils. The canal is surrounded by several concentric lamellae. The periosteum, which is best studied in sections from a bone which has been decalcified in chromic or picric acid, is a fibrous membrane composed of two layers, the inner of which contains many elastic fibres. In the outer layer numerous blood-vessels ramify and send from it branches to the Haversian canals of the bone. The periosteum ministers to the nutrition of the bone, partly on account of the blood- vessels it contains, partly, especially in young animals, on account of the existence between it and the bone of a layer of osteoblasts or bone- forming cells, a remainder of those which originally produced the bone. The marrow of bone is of a yellow colour in the shafts of the long bones, and is there largely composed of adipose tissue, but in the can- cellated tissue it is red, the colour being partly due to the large amount of blood in its vessels. This red marrow is chiefly composed of round nucleated cells — the marrow-cells (fig. 63, e-i) — which resemble large lymph-corpuscles, and, like these, are amoeboid. There are also to be seen mingled with them a number of corpuscles somewhat smaller in size, but nucleated and amoeboid, and of a reddish tint (fig. 63, j-t); these are believed to be cells in process of development into coloured MARROW 53 blood-corpuscles (hcematoblasts). Lastly the marrow contains a certain number of very large cells with multiple nuclei, the myeloplaxes ifig. 63, a, b, c, d). These are especially numerous wherever bone is becoming absorbed. The marrow is very vascular, the capillaries and veins being large and thin-walled ; indeed, according to some authorities, © % <® % l g Fig. C3. — Cells of the red marrow of the guinea-pig. (Highly magnified.) a, a large cell, the nucleus of which appears to be partly divided into three by constrict: 6. a cell the enlarged nucleus of - an appearance of being constricted into a number of smaller nuclei ; c, a so-called giant-cell or myeloplaxe with many nuci._. smaller myeloplaxe with three nuclei : e-i, proper cells of the marrow ; j-t, various forms of coloured nucleated cells, some in process of division. the walls of the capillaries are imperfect, so that there is an open com- munication between them and the interstices of the tissue, and in this way it is supposed that the coloured blood-disks, which are believed to be produced from the coloured nucleated cells of the marrow, may get into the circulation. 54 THE ESSENTIALS OF HISTOLOGY LESSON XIV. DEVELOPMENT OF BONE. 1. Mount in Canada balsam a section of the lower jaw of a foetus which has been stained in bulk with magenta or hematoxylin and embedded in paraffin. 1 Find the part where the lower jaw-bone is becoming ossified, and carefully study the appearances which it presents. The bone is prolonged in the form of osteogenic fibres which are covered with osteoblasts. 2. Intrarnembranous ossification may also be studied in the parietal bone of a fcetus which has been preserved in Midler's fluid. Apiece of the growing edge is scraped free from its investing membranes and mounted in glycerine or Farrant. 3. Moimt in Canada balsam sections of a fcetal limb which has been stained with magenta. The bones will be found in different stages of ossification, those of the digits being least developed. Make sketches illustrating the three chief stages of endochondral ossification. Notice the peculiar ter- minal ossification of the third phalanx. 4. Make with a sharp scalpel a longitudinal section at the line of ossifica- tion in a more advanced bone which has not been decalcified. These sections will show the mode of progress of the calcification. The sections can be mounted in Farrant's solution. True bone is essentially formed in all cases by an ossification of connective tissue. Sometimes the bone is preceded by cartilage, which first of all becomes calcined, and this is then invaded, and for the most part removed, by an embryonic tissue which re-deposits bony matter in the interior of the cartilage, whilst at the same time layers of bone are being formed outside underneath the periosteum. This is intracar- tilaginous or endochondral ossification. Sometimes the bone is not preceded by cartilage, and then the only process which occurs is one corresponding to the subperiosteal ossification of the former variety ; the ossification is then known as intrarnembranous. Ossification in Cartilage. — This may be described as occurring in three stages. In the first stage the cells in the middle of the cartilage become enlarged and arranged in rows radiating from the centre (fig. 64), and fine granules of calcareous matter are deposited in the matrix. Simultaneously with this the osteoblasts underneath the 1 For the methods of staining and embedding 1 and 3, see Appendix, ' Embedding in Paraffin.' DEVELOPMENT OF BONE 55 periosteum deposit a layer or layers of fibrous lamella? upon the surface of the cartilage, and these lamelhe also become calcified (fig. 64, im). As they are formed some of the osteoblasts (o) are included between them and become bone-corpuscles. Fig. 64. — Section of phalangeal bone of human foetus, at the time of commencing ossification. (Magnified about 7.") diameters.) The cart the centre an irated from one another by dark-looking I matrix; im, layer of bone deposited underm riostenm ; o, layer of by which this layer has been formed. Some of the osteoblasts arc- already em- bedded in the new bone as lacun®. Tl becoming enlarged and ft and arranged in row.- above and below the calcified centre. At the ends of the carti age the cells are small and the groups are irregularly arranged ; the fibrous periosteum is nut sharply marked <>tV from the cartilage. In the second stage some of the subperiosteal tissue eats its way through the newly formed Layer of bone and into the centre of the cal- cified cartilage (fig. 65, ir). This is freely absorbed before it, so thai large spaces are produced which are filled with osteoblasts and contain 50 THE ESSENTIALS OF HISTOLOGY numerous blood-vessels which have grown in at the same time. The spaces are termed medullary spaces, and this second stage may be termed the stage of irruption. Fig. G5. — Section of part of ONE OF THE LIMB-BONES OF A FCETAI. CAT. AT A HOKE ADVANCED STAGE OF OSSIFI- CATION THAN IS iuimu:- SENTED IX FIG. 64, AND SOMEWHAT MORE HIGHLY MAGNIFIED. The calcification of the cartilage- matrix has advanced from the centre, and is extending between the groups of cartilage-cells which are arranged in character- istic rows. The subperiosteal bony deposit dm) has extended pari passu with the calcification of the cartilage-matrix. The cartilage-cells in the primary areola; are mostly shrunken and stellate : in some cases they have dropped out of the space. At ir and in two other places an irrup- tion of the subperiosteal tissue, composed of ramified cells with osteoblasts and growing blood- vessels, has penetrated the sub- periosteal bony crust, and has begun to excavate the secondary areolae or medullary spaces ; p, fibrous layer of the periosteum ; o, layer of osteoblasts, some of them are embedded in the osseous layer as h.me-corpuscles in la. cunse : 6/, blood-vessels occupied by blood-corpuscles. Beyond the line of ossific advance the perios- teum may be noticed to be dis- tinctly incurved. This incurva- tion is gradually moved on. the cartilage expanding behind it until the head of the hone is reached, when it forms the peri- osteal notch or groove represented in fig. 66, p. 57. In the tliird stage of endochondral ossification there is a gradual advance of the ossification towards the extremities of the cartilage, and at the same time a gradual deposition of fresh bony lamella 3 and spicules on the walls of the medullary spaces, and on the surface of the new bone under the periosteum. The advance into the cartilage always takes place by a repetition of the same changes, the cartilage- cells first enlarging and becoming arranged in rows, the matrix between the rows becoming calcified, and then the calcified cartilage becoming excavated from behind by the osteoblastic tissue so as to form new medullar}- spaces (fig. 67). The walls of these are at first formed DEVELOPMENT OF BONE 57 only by remains of the calcified cartilage-matrix (fig. 67, c), but they soon become thickened by lamella of fibrous bone I b) which are Fig. 66. — Longitudinal sec- tion THROUGH THE UPPER HALF OF THE DECALCIFIED HUMERUS < >F A KKTAL SHEEP, AS SEEN UNDER A MAGNIFY- ING POWER OF ABOUT 30 DIAMETERS. ic, the part of the shaft which was primarily ossified in cartilage ; what remains of the primary bone is represented a- dark, en- veloped by the clear secondary deposit. The areola of the bone are occupied by embryonic mar- row with osteoblasts, and blood- vessels variously cut, represented a- dark lines. One long straight vessel the line of ossification far into the cartilaginous head, most of the others loop round close to the cartilage. At one or two places in the older parts of the bone elongated groups of cartilage- cells (c) may .-till be seen, which have escaped absorption, im. the part of the bone that has been ossified in membrane, that is to say. in the osteoblastic tissue under the periosteum. It is well marked off from the central por- tion, and is bounded, peripherally, by a jagf e projections of which are indistinctly seen to be pro aches of osteo- genic fibre-. A row of osl • the superficial layer of the bone. The subperiosteal layer is prolong'-.] above into the thicken- ing I/O, which encroacl the earl ad of the bone, and in which are seen, amongst numerous osteoblasts and a few blood-vessels, the straight longitudinal osteogenic fibres (of), ind some other fibres crossing them, and perhaps representing fibres of sharper. The calcareous salts havu - removed by an acid, the granular deposit passing up between the rows of cartilage-cells is not seen in this specimen; it would have extended as far a- a line joining the marks x x. Observe the general tendency of | ous trabecule and the vascular channels between them to radiate from the original centre of ossifi- cation. Thi- is found to prevail more or less in all bom ■ they are first formed, i the direction of the trabecular may afterwards become modified in relation with varying physio- logical conditions, and es| a- the result of pressure iu dif- ferent directions. - deposited by the osteoblasts, and between which bone-corpuscles become included, as in the case of the subperiosteal bone. The latter 58 THE ESSENTIALS OF HISTOLOGY advances pari passu with the endochondral calcification, but beyond this the uncalcified cartilage grows both in length and breadth, so that the ossification is always advancing into larger and larger portions of cartilage ; hence the endochondral bone as it forms assumes the shape of an hour-glass, the cylindrical shape of the whole bone being main- tained by additions of periosteal bone to the outside (see fig. 60). The Fig. 67. — Part of a loxgi- xrnixAi. section of the DEVELOPING FEMUR OF THE rabbit. (Drawn under a magnifying power of 350 diameters.) a, rows of flattened cartilage-cells ; 6, greatly enlarged cartilage- close to the advancing bone, the matrix between is parti; calcified; c, d, already formed the osseous trabecule being covered with osteoblasts ( i i. except here and there, win-re an osteoclast (/> eroding parts of the tral THE ESSENTIALS OF HISTOLOGY stained, wash it in water and with needles break the fibres up in Farrant's solution into as fine fibrils as possible. Cover and examine with a high power. 3. Tear off a small shred of the muscular coat of a piece of intestine which has been from -J4 to 48 hours in (£ per cent.) bichromate of potash solution. Hold the shred with forceps in a drop of water and fray it out with a needle. In this process many cells will be set free and can be seen with a low power. The preparation may then be covered and examined with a high power. Sketch one of the cells. Then allow dilute logwood to pass under the cover- glass and lastly a drop of glycerine. Sketch another cell after staining. Measure two or three cells and their nuclei. Voluntary muscle is composed of long cylindrical fibres, measuring on an average about 3-^ inch in diameter in mammalian muscles, but having a length of an inch or more. Each fibre has an elastic sheath, the sarcoiemma, which encloses the contractile substance. The sarco- lemma is seldom distinct, unless the contained substance becomes broken (fig. 69). Fig. 69. — Sarcolemma of mammalian mus- cle, highly magni- FIED. The fibre is represented at a place where the mus- cular substance has be- come ruptured ami lias shrunk away, leaving the sarcoiemma (with a nucleus adhering to it) clear. The fibre had been treated with serum acidu- lated with acetic acid. Fig. 70. — Muscular FIBRE i>F A MAMMAL EXAMINED FRESH IN SERUM, HIGHLY MAG- NIFIED. THE SURFACE OF THE FIBRE BEING ACCURATELY FO- CUSSED. The nuclei are seen on the flat at the surface of the fibre, and iu profile at the edges. The contractile substance of the fibre is characterised by the alter- nate dark and light stripes which run across the length of the fibre ; hence the name, cross-striated or striped muscle. On focussing, it STRUCTURE OF MUSCLE 63 can be seen that the stripes pass through the whole thickness of the fibre ; they may therefore be looked upon as representing alternate disks of dark and light substance. If the surface be very carefully focussed, double rows of granules are seen lying in or at the bounda- ries of the light streaks, and very fine longitudinal lines may, with a good microscope, be detected running through the dark streak, and uniting the minute granules (fig. 70 1. These fine lines, with their enlarged extremities the granules, are known as muscle-rods ; they are more conspicuous in the muscles of insects. -is -an- -z's Fig. 72. — Diagramma- tic REPRESENTATION OF A MUSCLE-* ASE. en, muscle-prism, i ingof a bundle of muscle- rods : it, fluid substance. Fin 71. — Portion of a medium- BIZED HUMAN MUSCULAR FIBRE, SHOWING THE INTERMEDIATE LINE MENTIONED IN THE TEXT. If instead of focussing the surface of the fibre it be observed in its depth. a different appearance is frequently visible, namely a line dotted line bisecting each clear stripe (tig. 71) : but this appearance is probably due to an optical effect caused by the light being transmitted between disks of different refrangibility. The fine line bisecting the clear stripe is. however, taken by many histolo- giflte to represent a definite structure, and is often known as Krause's mem- brane, having l>een described by Krause as connected with the sarcolemma and dividing the muscle-fibre into so many flat compartments. Krause further de- scribed these compartments as divided longitudinally by fine membranes, so that tlie muscle-substance may, according to hirn.be regarded as co little cylindrical ' cases ' (fig. 72) each containing in the centre a portion of the dark disk, and. above and below this, portions of the light disks (which are fluid according to this author). 1 1 For other views repanlinpr the structure of striated muscular fibre, the student is referred to Quain's Anatomy, 9th edition, vol. ii. pp. 127 to 129. C4 THE ESSENTIALS OF HISTOLOGY Besides the sarcolernma and striated substance, a muscular fibre also exhibits a number of oval nuclei which have the usual reticular structure of cell-nuclei. Sometimes there is a little granular substance (proto- plasm) at each pole of the nucleus. In mammalian muscle the nuclei lie immediately under the sarcolernma (figs. 69, 70), except in certain fibres, e.g. those which compose the red muscles of some animals, such as the hare and rabbit, and which occur scattered amongst the ordinary fibres in mammalia generally. In these the nuclei are distributed through the thickness of the fibre, and this is also the case in all the muscular fibres of the frog. The transverse section of a muscle shows the fibres to be nearly cylindrical in figure. Between the fibres there is a certain amount of areolar tissue, which serves to support the blood-vessels and also unites them mto fasciculi ; the fasciculi are again united together by a larger amount of this intramuscular connective tissue. On examining the transverse section of a fibre with a high power, it is seen to be subdivided everywhere into small angular fields, the areas of Cohnheim. These probably represent sections of tbe longi- tudinal fibrils into which a muscular fibre splits after death, or after being hardened in certain reagents, e.g. alcohol, chromic acid, or osrnic acid. Fig. 73. — Section of a muscular fibre showing areas of coiinheim. Fig. 74. — Living muscle of -water- beetle (dytiscis marginalia). (Highly magnified.) s, sarcolernma ; a, dim stripe ; b, bright stripe; c, row of dots in bright stripe, which seem to be the enlarged ends of rod-shaped particles, d. In the muscles of insects the stripes are relatively broad, and their structure can be more readily seen than in mammals. In the living fibres from the muscles of tbe legs, the appearance of fine longitudinal lines traversing the dark stripes, and terminating within the light stripes in rows of dots, is very obvious. When the fibres contract, the light stripes are seen, as the fibre shortens and thickens, to become STRUCTURE OF MUSCLE 65 dark, an apparent reversal being thereby produced in the striaB. This reversal is due to the enlargement of the rows of dark dots, and the formation by their juxtaposition and blending of dark disks, whilst the muscular substance between these disks has by contrast a bright appearance. The wing-muscles of insects are easily broken up into very fine fibres or fibrils, which also show alternate dark and light stria?. The number and relative thickness of these differ, however, considerably, according to the amount of stretching of the fibres (fig. 75). Muscle- rods are not seen in these fibres. e > _ e t t e e e m ■ be m ,5c m Fig. 75. — Fibres of the wixg-musci.es of an insect. The fibres are in different conditions of extension, from A least extended, to D most ex- tended, e, e, chief substance of the fibre ; m, m, intermediate lines or disks ; the light bands, be, on either side of these only come to yiew when the fibre is sufficiently stretched (C) ; with further extension (D), the middle of the dark band appears lighter, fi.~ In muscular tissue which has been hardened in alcohol and certain other reagents, the structural appearances are a good deal altered from those of the living muscle, although the cross-striae are still very obvious. There is also a considerable tendency for the fibres to split up longi- tudinally into fibrils, and by some authorities the finest of such fibrils are regarded as the ultimate elements of the fibre. Certain other reagents, such as dilute hydrochloric acid, cause a transverse splitting of the fibres into disks, and these effects of reagents led Bowman to form the opinion that the muscular substance may be in reality composed of minute prismatic particles set side by side in rows or planes to form the disks, and adhering end to end longitudinally to form the fibrils. To these constituent particles of the muscular substance he gave the name of ' sarcous elements.' When living muscular fibres are examined by polarised light, the whole of the muscular substance except the muscle-rods is seen to be doubly refracting, looking bright in the dark field produced by crossing the axes of the Nichol's prisms. Contracted muscle and dead muscle show, however, alternate bands of dark and light under those circum- stances. Ending of muscle in tendon. — A small tendon-bundle passes to 66 THE ESSENTIALS OF HISTOLOGY each muscular fibre and becomes firmly united with the sarcolemma, which extends over the end of the fibre (fig. 76). Further, the areolar tissue between the tendon -bundles is continuous with that which lies between the muscular fibres, so that the connection of a muscle to its tendon is very firm. p — — s Fig. 76. — Termination of a mus- cular fibre ix tendon. m, sarcolemma ; s, the same membrane passing over the end of the fibre; p, extremity of muscular substance, c, retracted from the lower end of the .-areolemma-tube; /, tendon-bundle passing to be fixed to the sarcolemma. Fig. 77. — Capillary vessels of muscle. Blood-vessels of muscle. — The capillaries of the muscular tissue are very numerous. They run, for the most part, longitudinally, with transverse branches, so as to form long oblong meshes (fig. 77). In the red muscles of the rabbit and hare, the transverse capillaries have small dilatations upon them. No blood-vessels ever penetrate the sarcolemma. Lymphatic vessels, although present in the connective-tissue sheath (perimysium) of a muscle, do not penetrate between its component fibres. The nerves of voluntary muscles pierce the sarcolemma and ter- minate in a ramified expansion known as an end-plate (see Lesson XIX.). STRUCTURE OF MUSCLE 67 Voluntary muscular fibres are developed from embryonic cells of the mesoderm, which become elongated, and the nuclei of which become multiplied, so as to produce long multi-nucleated fusiform or cylindrical fibres. These become cross-striated at first along one side, the change gradually extending around the fibre and also towards the centre ; but the middle of the fibre, to which the nuclei are at first confined, remains for some time unaltered (fig, 78 1. Eventually the change in structure extends to this also, and the nuclei pass gradually to occupy their ordinary position under the sarcolemma, which by this time has become formed. Fig. 78. — Developing miscular fibre, from fcetus of 2 MONTHS. p, central protoplasm with several nuclei, n, scat- tered in it ; s, commen- cing sarcolemma, with striated muscular sub- stance developing im- mediately beneath it. Fig. 79.— Mttsculab fibre-cells from the mttscu- lab coat of" the small intestine, highly mag- NIFIED. A. A complete cell, showing the nucleus with intra-nuclear network, and the longitudinal fibrillation of the cell-sub- stance, with finely vacuolated protoplasm between the fibrils. B. A cell broken in the process of isolation ; the delicate enveloping membrane projects at the broken end a little beyond the substance of the cell. Involuntary or plain muscular tissue is composed of long, some- what flattened, fusiform cells (fig. 79), which vary much in length, but are usually not more than -^ inch long. Each cell has an oval or F 2 68 THE ESSENTIALS OF HISTOLOGY rod-shaped nucleus, which shows the usual intra-nuclear network and commonly one or two nucleoli. The cell -substance is longitudinally striated, but does not exhibit cross-striae like those of voluntary muscle. There appears to be a delicate sheath to each cell. There is a little intercellular cementing substance uniting the cells together, and which can be stained by nitrate of silver. The fibres are collected into fas- ciculi. Plain muscular tissue is found chiefly in the walls of hollow viscera ; thus it forms the muscular coat of the whole of the alimentary canal below the oesophagus, and occurs abundantly in the rnuscular coat of that tube also, although it is here intermixed with cross-striated muscle ; it is found also in the mucous membrane of the alimentary canal ; in the trachea and its ramifications ; in the urinary bladder and ureters ; in the uterus, Fallopian tubes, and ovary ; in the pro- state, the spleen, and muscle of Midler in the orbit, and in the ciliary muscle, and iris. The walls of gland-ducts also contain it, and the middle coat of the arteries, veins, and lymphatics is largely composed of this tissue. It occurs also in the skin, both in the secreting part of the sweat-glands, and in small bundles attached to the hair-follicles ; in the scrotum it is found abundantly in the subcutaneous tissue idartos). The muscular tissue of the heart constitutes a special variety of involuntary muscular tissue (cardiac), and will be described along with that organ. 69 LESSON XVII. STRUCTURE OF NERVE-FIBRES. 1. Tease a piece of fresh nerve in saline solution, injuring the fibres as little and obtaining them as long and straight as possible. Study the rnedullated fibres, carefully noticing all the structures that are visible — viz., nodes of Eanvier, nuclei of primitive sheath, double contour of medullary sheath, medullary segments, &c. Measure the diameter of half a dozen fibres. Draw a short length of a fibre very exactly. 2. Prepare a piece of the sympathetic nerve in the same way. Measure and sketch as before. 3. Separate (in dilute glycerine or Farrant) into its fibres a small piece of nerve that has been twenty-four hours in ^ per cent, osmic acid. The nerve should have been moderately stretched on a piece of cork by means of pins before being placed in the acid. Keep the fibres as straight as possible and only touch them near their ends with the needles. Sketch two portions of a fibre under a high power, one showing a node of Eanvier and the other a nucleus of the primitive sheath. Look for fibres of Eeruak. Measure the length of the nerve -segments between the nodes of Eanvier. 4. Mount in Canada balsam sections of a nerve which has been hardened in picric acid and stained with picro- carmine. The nerve should have been stretched out before being placed hi the hardening solution. Examine the sections first with a low and afterwards with a high power. Notice the lamellar structure of the perineurium, the varying size of the nerve-fibres, the axis cylinder in the centre of each fibre, &c. Measure the diameter of five or six fibres, and sketch a small portion of one of the sections. Nerve-fibres are of two kinds, rnedullated and non-medullated. The cerebro- spinal nerves and the white matter of the nerve-centres are composed of rnedullated fibres ; the sympathetic and its branches is chiefly made up of non-medullated. The rnedullated or white fibres are characterised, as their name implies, by the presence of the so-called medullary sheath or white substance. This is a layer of soft substance, chiefly of a fatty nature, which encircles the essential part of a nerve-fibre, viz. the axis-cylinder. Outside the medullary sheath is a delicate but tough homogeneous membrane, the primitive sheath or nucleated sheath of Schwann, but 70 TPIE ESSENTIALS OF HISTOLOGY this is not present in all niedullated fibres, being absent in tnose which are within the nerve-centres. The medullary sheath is composed of a highly refracting fatty Fig. 80. — White or medullated nerve - fibres, showing the sinuous outline and double contours. Fig. 81. — Portions of two nerve-fibres stained with osmh acid (from a young rabbit). (425 diameters.) R, R. Nodes of Ranvier, with axis-cylinder pa-sing through, a, primitive sheath of the nerve, e, opposite the middle of the segment, indicates the nucleus and proto- plasm lying between the primitive sheath and the medullary sheath. In A the nodes are wider, and the intersegmental substance more apparent than in B. material, which gives a characteristic dark contour and tubular appear- ance to the nerve-fibres. It affords a continuous investment to the axis-cylinder, except that it is interrupted at regular intervals in the STRUCTURE OF Fig. 82. — A -mall part of a medul- LATED FIBRE. HIGHLY MAGNIFIED. The fibre looks in optical section like a tube — hence the term tubular, formerly applied to these fibres. Two partial breaches of con- tinuity are seen in the medullary sheath, which at these places exhibits a tendency to split into lamina;. The primr here and there apparent outside the medul- lary sheath, and the delicate striae which are visible : the fibre pro- bably indicate the fibrillated aiis-cy'.inder. Fig. &4. — Two portions of m emulated NERVE-FIBRE-. AFTER TREATMENT Willi OSMIC A< II', 3HOWE5G THE AXJS- i VLINIiER. AND THE MEDULLARY AND PRIMITIVE -HEATHS. of Ranvier. B. Middle of an inter- node with nucleus, c, axis-cylinder, pro- jecting : /•. primitive sheath, within which • stained dark by the osmic acid, is somewhat retracted. XERVE-FLBRES 7x course of the peri- pheral nerve-fibres, the axis-cylinder at these places being encompassed only by the primitive sheath. Hence the primitive sheath appears at these spots to pro- duce a constriction in the nerve- fibre, and the interruptions of the medullary sheath are accord- ingly known as the constrictions or nodes of Banvier ifig. 81, b, r ; fig. 83, li, the term nodes being ap- plied from the resem- blance which they bear to the nodes of a bamboo. The length of nerve be- tween two successive nodes may be termed an intemode ; in the middle of each inter- node is one of the nuclei of Schwann's sheath. Besides these interruptions the medullary sheath shows a variable number of oblique clefts i fig. 83 1 which subdivide it into irregular portions, which have been termed medullary segments, but there is reason to believe that the clefts are artificially produced. I -I Osmic acid stains the Fig. 83. -Nerve- mec l u H arv sheath FIBRE STAINED with osmic acid, black. 72 THE ESSENTIALS OF HISTOLOGY The axis-cylinder, which runs along the middle of the nerve-fibre, is a soft transparent thread which is continuous from end to end of the nerve. On account of the peculiar refractive power of the medullary sheath Fig. 85. — AXIS- CYLINDER, HIGHLY MAGNIFIED, SHOW- ING THE FIBRILS COMPOSING IT. Fig. 86. — Portion of the network of fibres of remak from the i'neumo- gastric of the dog. n, nucleus ; p, protoplasm sur- rounding- it ; b, striation caused by fibrils. Fig. 87. — A small bi-ndle of NERVE-FIBRES FROM THE SYMPATHETIC NERVE. The bundle is composed of pale nerve-fibres, with the exception of the fibre m. m. which is en- closed here and there by a thin medullary sheath ; n, n, nuclei of pale fibres. it is difficult to see the axis-cylinder in the fresh nerve except at the nodes, where it may be observed stretching across the interruptions in the medullary sheath, andit may also sometimes be seen projecting from a broken end of a nerve-fibre. It is longitudinally striated, being really made up of exceedingly fine fibrils (ultimate fibrils, fig. 85), which are darkly stained by chloride of gold. Staining with nitrate STRUCTURE OF NERVE-FIBRES 73 of silver produces a curious transversely striated appearance in the axis- cylinder, but it is not known if this indicates a pre-existent structure. Intermingled with the medullated fibres there may always, even in the cerebro-spinal nerves, be found a certain number of pale fibres devoid of the dark double contour which is characteristic of the presence of a medullary sheath. There are the non-medullated fibres, also called, after their discoverer, fibres o/Bemak I fig. 86 1. They frequently branch, which the medullated fibres never do except near their termination, and they are beset with numerous nuclei which perhaps belong to a delicate sheath. The sympathetic nerve is in many animals chiefly made up of fibres of this nature, but in some animals, on the other hand, most of the fibres of the sympathetic possess some small amount of medullary sheath (fig. 87). Fig. 88. — Section of the saphenous nerve (human), hade after being stained in osm1c acid and subsequently hardened in alcohol. (Drawn as seen under a very low magnifying power.) ep, epineurium. or general sheath of the nerve, consisting of connective-tissue bundles of variable -iz. separated by cleft-like areolas, which appear as a network of clear lines with here ami there fat-cells ami blood-vessels : /, /, funiculi enclosed in their lauiellated connective-tissue sheaths (perineurium, /') : rnd. interior of funiculus, showing the cut ends of the medullated nerve-fibres, which are embedded in the connective tissue within the funiculus (endoneurium >. The fat-cells and the nerve-fibres are darkly stained by the osmic acid, but the connective tissue of the uerve is only slightly stained. Structure of the nerve-trunks. — In their course through the body the nerve-fibres are gathered up into bundles or funiculi, and the funiculi may again be united together to form the nerves which we meet with in dissection. The connective tissue which unites the 74 THE ESSENTIALS OF HISTOLOGY funiculi and invests the whole nerve, connecting it to neighbouring parts and conveying to it blood-vessels, lymphatics, and even nerve- fibres destined for its coats, is termed the epineurium (fig. 88, ep). That which ensheaths the funiculi is known as the perineurium (fig. 88, per). It has a distinctly lamellar structure (fig. 89, p), the lamella? Fig. 89. — Part of a section of one of the funiculi of the sciatic nerve of man. (Magnified.) P, perineurium, consisting of a number of closely arranged lamella?. En, processes from the perineurium, passing into the interior of the funiculus, and becoming continuous with the endoneurium, or delicate connective tissue between the nerve-fibres. The connective- tissue fibrils of the endoneurium are seen cut across as fine points, often appearing to en- sheath the nerve-fibres with a circle of minute dots (fibril-sheath of Key and Retzius). Numerous nuclei of connective-tissue cells are embedded in the endoneurium ; r, section of a blood-vessel. being composed of connective tissue and covered on both surfaces by flattened epithelioid cells (fig. 90). Between the lamella? are clefts for the conveyance of lymph to the lymphatics of the epineurium. The delicate connective tissue which lies between the nerve-fibres of the funiculus is the endoneurium (fig. 88, end; fig. 89, En). It assists in Fig. 90. — Nerve-funiculus stained with nitrate of sil- ver, SHOWING THE OUTLINES OF EPITHELIOID CELLS OF THE PERINEURIUM. The dark crosses on the nerve-fibres at the nodes of Ranvier are due to the staining of the axis-cylinder and of a band of intercellular substance which encircles the axis-cylinder at the node (.constricting band of Ran, vier). supporting the longitudinally arranged meshwork of blood-capillaries, and its interstices communicate with the lymphatic clefts of the perineurium. The nerve- trunks themselves receive nerve-fibres (nervi nervorum) which ramify chiefly in the epineurium and terminate in this in end- bulbs. 75 LESSON XVIII. STRUCTURE OF NERVE-CELLS. 1. Tease in Farrant's solution or in dilute glycerine a sniall piece of a spinal ganglion that has been preserved with osinic acid. Notice the spheroidal ganglion -cells ; their large nuclei and distinct nucleoli. Look for cells which still retain the axis-cylinder process and for T-shaped junctions of nerve- fibres with this. 2. Prepare a piece of sympathetic ganglion in the same way. Cells may be foimd with three or more axis-cylinder processes. If from a rabbit observe that the cells are bi-nucleated. 3. Mount stained sections of ganglia in Canada balsam. These will serve to show the arrangement of the cells and fibres in a ganglion and the nucleated sheaths around the nerve-cells. 4. Tease out a portion of the grey matter from a piece of spinal cord that has been a day or two in dilute chromic acid (A per cent.). Before covering, look for the nerve-cells with a low power, and if possible get out one or two clear of the surrounding substance. Mount in water with a thick hair under the cover-glass. Notice the large branching cells some with a mass of pig- ment near the nucleus. Observe the fibrillation of the cell-processes. Notice also the reticular character of the tissue in which the cells are embedded. Many axis- cylinders will be seen in this preparation deprived wholly or partially of their medullary sheath, and their fibrillar structure can then also be well seen. Carefully sketch these appearances. To keep this preparation run very dilute logwood solution or osmic acid under the cover-glass, and when the cells are stained allow a drop of glycerine to pass in by diffusion. Measure two or three cells in each of the above preparations. Nerve-cells only occur in the grey matter of the nerve-centres, and in little groups on the course of certain of the peripheral nerves, these groups often causing nodular enlargements of the nerves, which are known as ganglia. The most important ganglia are those which are found upon the posterior roots of the spinal nerves, upon the roots of some of the cranial nerves, and upon the trunk and principal branches of the sympathetic nerve. Minute ganglia are also found very nume- rously in connection with the nerves which are supplied to involuntary muscular tissue, as in the heart, alimentary canal, bladder, uterus, £c. Nerve-cells vary much in size and shape ; they are mostly large, some being amongst the largest cells met with in the body, but others are quite small. The nucleus is generally large, clear, and 76 THE ESSENTIALS OF HISTOLOGY spherical, with a single large and distinct nucleolus. The shape depends a good deal on the number of processes, and the manner in which they come off from the cell. If there is but one process, the cell is generally spherical. This is the case with the cells of the Fig. 91. — Cell from a spinal ganglion. sh, nucleated sheath of the cell ; 11, »', the nerve-fibre which the single process of the cell, after a number of coils, joins. Fig 92. — Ganglion-cell of a frog, highly magnified. a, a, straight fibre ; b. b. coiled fibre ; c, smaller one joining it. Fig. 93. — A ganglion-cell ■within its SHEATH ; FROM THF. HUMAN SYMPATHETIC. (Highly magnified.) spinal ganglia (fig. 91) ; in these the single process, after a short course, joins one of the nerve-fibres which is traversing the ganglion. When there are two processes, they often go off in opposite directions STRUCTURE OF NERVE-CELLS 77 from the cell, which is thus rendered somewhat spindle-shaped, but occasionally they emerge at the same part, and the cell, being tapered in their direction, becomes pyriform (fig. 92). In these cases one fibre often coils spirally round the other (fig. 92, b) before they separate to proceed in opposite directions as the axis-cylinders of nerve-fibres. When there are three or more processes, the cell becomes irregularly angular or stellate. Sometimes, as in the sympathetic ganglia (fig. 93), all the processes appear to become nerve-fibres, but in other instances, as in the large cells of the grey matter of the spinal cord, only one Fig. 94. — Nerve-cell from spinal cord of ox, isolated after maceration in very dilute chromic acid. (Magnified 1~5 diameters.) The cell has a well-defined, clear, round nucleus, and a bright nucleolus. The cell processes are seen to be finely fibrillated, the fibrils passing from one process into another through the body of the cell, «, axis-cylinder process broken a short distance from the cell. process becomes the axis-cylinder of a nerve-fibre (process of Deiters), the others dividing and subdividing in a ramified manner until their further course can no longer be traced. Their ultimate branches appear to lose themselves in a network which pervades the whole of the grey matter. According to the number of their processes, nerve-cells are termed uni-, bi-, or multi-polar. Many nerve-cells, and notably those of the spinal cord, have a finely fibrillar structure. The fibrils can be traced into the branches of the cells and into the axis-cylinders of nerve-fibres which are connected with the cells (fig. 95). Otherwise the cells have a finely granular appearance ; often with a clump of black, brown, or yellow pigment- granules placed at one side of the nucleus. 78 THE ESSENTIALS OF HISTOLOGY In the ganglia the nerve-cells have a nucleated sheath (figs. 91- 93) which is continuous with the primitive sheath of the nerve-fibres with which they are connected. In the spinal ganglia, and in many of the ganglia at the roots of the cranial nerves, the cells are unipolar, :,r :]'■ Fig. 95. — Axis-cylinder process of nerve- CELL. x, x, portion of nerve- cell ; a, axis-cylinder process ; a', medullary sheath. Highly magni- fied. and the cell-process joins a traversing nerve-fibre by a T-shaped junction (fig. 91). In the sympathetic ganglia they are multipolar. The cells are disposed in aggregations of different size, separated by the bundles of nerve-fibres which are traversing the ganglion (fig. 96). STRUCTURE OF NERVE-CELLS 79 The ganglion if large is enclosed by an investing capsule of connective tissue which is continuous with the epi- and peri-neuriuni of the entering and issuing nerve-trunks. The structure of the nerve-centres and the arrangement of the cells and fibres in them are given hi Lessons XXXVI. to XXXIX. Fjg. 96. — Longitudinal section through the middle of a ganglion on the posterior root ok one of the sacral nerves of the dog, as seen under a low magnifying rower. a, nerve-root entering the ganglion : b, fibres leaving the ganglion to join the mixed spinal nerve; r. connective-tissue coat of the ganglion; d, principal group of nerve-cells, with fibres passing down from amongst the cells, probably to unite with the longitudinally coursing nerve-fibres by T-shaped junctions. Development. — The cells and fibres of the nervous tissue are developed from cells derived from the ectoderm or epiblast of the embryo. The nerve-fibres are at first developed as pale fibres like the fibres of Remak ; it is uncertain whether they are formed by the coalescence of a number of cells, or whether they grow out as the processes of nerve-cells. The medullary sheath is subsequently added. When a nerve is cut, the fibres beyond the section as far as their terminations undergo a process of degeneration, the medullary sheath being broken up and the axis-cylinder interrupted and eventually absorbed. New nerve-fibres are at length produced by a growth of the axis-cylinders in the proximal end of the nerve. 80 THE ESSENTIALS OF HISTOLOGY LESSON XIX. MODES OF TERMINATION OF NERVE-FIBRES. 1. Shell out a Pacinian corpuscle from a piece of cat's mesentery which has been kept for two or three days in -7 1 - per cent, chromic acid, and clear it as much as possible of adhering fat, but be careful not to prick or otherwise injure the corpuscle itself. Mount in water with a thick hair to prevent crushing with the cover-glass. Sketch the corpuscle under a low power, and afterwards draw under a high power the part of the core where the nerve enters and the part where it terminates. Notice the fibrous structure of the lamellar tunics of the corpuscle and the oval nuclei belonging to flattened epithelioid cells which cover the tunics. The distinct lines which when seen in the fresh corpuscle are generally taken for the tunics, are really the optical sections of these flattened cells. 2. Mount in Farrant one or more sections of a rabbit's cornea which has been stained with chloride of gold. Notice the arrangement in plexuses of the darkly stained nerve-fibres and fibrils, (1) in the connective-tissue sub- stance, (2) under the epithelium and (3) between the epithelial cells. Make one or two sketches showing the arrangement of the fibrils. 3. Spread out a small piece of muscle which has been stained with chloride of gold by Lowit's method, and examine it with a low power to find the nerve-fibres crossing the muscular fibres and distributed to them. Try and separate those parts of the muscular fibres to which nerves appear to go, and mount them in glycerine. Search thoroughly for the close terminal ramifications (end-plates) of the axis -cylinders immediately within the sarcolemma. It is rather difficult to dissociate the fibres, and much patience is some- times required in searching for the nerve-terminations, but when they are found the trouble is amply repaid. 1 Modes of ending of sensory nerve-fibres. — Nerve-fibres which are distributed to sensory parts end either in special organs or in terminal ramifications or plexuses. There are three chief kinds of special organs, termed respectively Pacinian corpuscles, tactile corpuscles, and end-bulbs. In the tactile corpuscles and end-bulbs the connective- tissue sheath of a medullated fibre expands to form a somewhat solid bulbous enlargement, which is either cylindrical or spheroidal in the end-bulbs and ellipsoidal in the tactile corpuscles. Li both kinds of end- organ there is a capsule of connective tissue within which is generally a sort of core containing numerous nucleated cells. As the nerve-fibre enters the corpuscle (which in the tactile corpuscle only happens after it has reached the distal part of the corpuscle having wound spirally 1 For methods of staining with chloride of gold see Appendix. MODES OF TERMINATION OF NERVE-FIBRES 81 once or twice round it) it loses its sheaths and is prolonged as an axis- cylinder only, which terminates after either a straight or a convoluted course within the organ (see figs. 98 to 101). Tactile corpuscles occur Fig. 97. — Section of skin showing two papill.e and deeper layers of epidermis. a, vascular papilla with capillary loop passing from subjacent vessel, c ; 6, nerve-papilla with tactile corpuscle, t. The latter exhibits transverse fibrous markings ; d, nerve passing up to it ; /, /, sections of spirally winding nerve-fibres. Ep Fig. 08.— Tactile corpuscle within a papilla of the >kin < >f the hand, stained with chloride of gold. The convolutions of the nerve- fibres within the corpuscle are seen. Ep. epidermis. Fig. 99. — Simple tactile end-organs prom the clitoris of the rabbit. Fig. ino._ Cylindrical END-BULR FROM THE CONJUNCTIVA OF THE CALF. 82 THE ESSENTIALS OF HISTOLOGY Fig. 101. — End-bulb from the human conjunctiva. a, nucleated capsule ; b, core, the outlines of its cells are not seen : c. entering fibre, branching, and its two divisions passing to terminate in the core at d. Fig. 102. — Tactile corpuscles from the duck's tongue. A, composed of three cells, with two interposed disks, into which the axis-cylinder of the nerve, n, is observed to pass; inB there is but one tactile disk enclosed between two tactile cells. Fig. 103.— Magnified view of a Pacinian* body from the cat's mesentery. s. stalk with nerve-fibre passing to the corpuscle. One or two capillaries are seen issuing from it between the tunics. Fig. 104. — Part of Pacinian body, showing the nerve-fibres entering the core. From an osmic acid preparation. ms, entering nerve-fibre, the medullary sheath of which is stained darkly, and end- abruptly at the core; ps, prolongation of primitive -heath, passing towards the outer part of the core: e.f. axis-cylin- der passing through the core of the central fibre: e, -"me of the inner tunics of the corpuscle, enlarged where they abut against the canal through which the nerve-fibre passes — the dots within them are sections of the fibres of which they are composed ; n. nuclei of the tunics: n', nuclei of the endo- neurium, continued by others in the outer part of the core. MODES OF TERMINATION OF NERVE-FIBRES 83 in some of the papilla? of the skin of the hand and foot, in sections of which they may be afterwards studied (see Lesson XXIII.) End- bulbs are found in the conjunctiva of the eye, where in most animals they have a cylindrical or oblong shape (fig. 100), but in man are spheroidal (fig. 101). They have also been found in papilla? of the lips and tongue, and in the epineurium of the nerve -trunks, and somewhat similar sensory end- organs also* occur in the integument of the external genital organs of both sexes (fig. 99). In the skin covering the bill, and in the tongue of certain birds (e.g. duck), a simple form of end- organ occurs, consisting of two or more cells arranged in rows within a capsule, with the axis-cylinder terminating in flattened expansions between the cells (corpuscles of Grandry, fig. 102). The Pacinian corpuscles are larger, and have a more complex structure, than the tactile corpuscles and end-bulbs (fig. 103). They are composed of a number of concentric coats arranged like the layers of an onion, and enclosing the prolonged end of a nerve-fibre. A single medullated nerve -fibre goes to each Pacinian corpuscle encircled by a prolongation of perineurium, and within this by endoneurium ; when it reaches the corpuscle, of which it appears to form the stalk, the lamellae of the perineurium expand to form some of the tunics of the corpuscle. The nerve passes on, piercing the other tunics, and still provided with medullary sheath, and surrounded by endoneurium, to reach the centre of the corpuscle. Here the endoneurium is prolonged to form a sort of soft cylindrical core, along the middle of which the nerve-fibre, now deprived of its medullary and primitive sheaths, passes in a straight course as a simple axis-cylinder (fig. 104, c.f.) to termi- nate at the farther end of the core in a bulbous enlargement. Occa- sionally the fibre is branched. The tunics of the corpuscle are composed of connective tissue, the fibres of which for the most part run circularly. They are covered on both surfaces with a layer of flattened epithelioid cells, and here and there cleft-like lymph-spaces can be seen between them like those between the layers of the perineurium (see p. 74 I. When sensory nerve-fibres terminate in plexuses, they generally branch once or twice on nearing their termination. The sheaths of the fibres then successively become lost, first the connective tissue or peri- neural sheath, then the medullary sheath, and lastly the primitive sheath, the axis-cylinder being alone continued as a bundle of primitive fibrils (fig. 105, n). This branches and joins with the ramifications of the axis-cylinders of neighbouring nerve-fibres to form a primary plexus. From the primary plexus smaller branches (a) come off, and these form a secondary plexus (e) nearer the surface, generally imme- diately under the epithelium if the ending is in a membrane covered by that tissue. Finally, from the secondary plexus nerve-fibrils proceed and form a terminal plexus or ramification amongst the epithelium- cells i fig. 10(3, p), the actual ending of the fibrils being generally in little knob-like enlargements (b). Such a mode of ending in terminal o2 84 THE ESSENTIALS OF HISTOLOGY *«*£S3ggg! Fio. 105. — Sub-epithelial plexus of the cornea treated with chloride of gold. (Ranvier.) n, branch of primary plexus ; a, small branch, passing to join the sub-epithelial plexus, e. Fig. 106 — Vertical section of cornea stained with chloride of gold. (Ranvier.) n, r, primary plexus in connective tissue of cornea ; a, branch passing to sub-epithelial plexus, s ; p, intra-epithelial plexus ; b, terminations of fibrils. MODES OF TERMINATION OF NERVE-FIBRES 85 plexuses is most characteristically seen in the cornea of the eye. The nerve-fibrils may be brought distinctly into view by staining with chloride of gold, and then the fibrillar structure of the ramifications of the axis-cylinders also becomes very apparent. Fig. 107. — Nerve-ending in muscular fibre of a lizard (Lacerta viridis) a, end-plate seen edgeways ; 6, from the surface ; s, s, sarcolemma ; p, p, expansion of axis- cylinder. In 6 the expansion of the axis-cylinder appears as a clear network branching from the divisions of the medullated fibres. Fig. 108. — Terminal ramifications of the axis-cylinder in end-plates of muscle, stained with chloride of gold. (Ranvier.) Ending of motor nerves. — Lastly the nerves to muscles also ter- minate either in special organs or in plexuses. The latter is the case with the nerves going to involuntary muscle, and here the primary plexuses are generally furnished with ganglion-cells in abundance. From these other nerve-fibres pass which form secondary plexuses and terminal ramifications amongst the contractile fibre-cells. These nerves will be more fully studied in connection with the intestine (see Lesson XXIX. i 86 THE ESSENTIALS OF HISTOLOGY In voluntary muscle the nerves, which are always rnedullated, ter- minate in special organs, the so-called end-plates. A rnedullated fibre will branch two or three times before terminating, and then each branch passes straight to a muscular fibre. Having reached this, the primitive sheath of the nerve-fibre is continued into the sarcolemma of the muscle, the medullary sheath stops short, and the axis-cylinder ends in a close terminal ramification with varicosities upon its branches (figs. 107, 108). This ramification is embedded in a granular nucleated protoplasmic mass which lies* between the sarcolemma and the cross- striated muscular substance. In some cases the ramification is restricted to a small portion of the muscular fibre, and forms with the granular bed a slight prominence (eminence of Doyere). This is the case in mammals. In the lizard the ramification is rather more extended than in mammals, whilst in the frog it is spread over a considerable length of the fibre. 87 LESSON XX. STRUCTURE OF THE LARGER BLOOD-VESSELS. 1. Sections of a medium-sized peripheral artery and vein. In this pre- paration the limits of the vascular coats can be well seen and also the differ- ences which they present in the arteries and veins respectively. The sections may either be stained with hematoxylin and mounted in Canada balsam, or they may be stained in dilute magenta anil mounted in glycerine and water. 2. Mount in Canada balsam a thin slice cut from the inner surface of an artery which, after having been cut open longitudinally and washed with distilled water, has been treated with nitrate of silver solution and exposed to the light in spirit. This preparation will show the outlines of the epithelioid cells which line the vessel. 3. A piece of an artery which has been macerated for two or three days in 30 per cent, alcohol (1 part rectified spirit to two pai-ts water i is to be teased so as to isolate some of the muscular cells of the middle coat and portions of the elastic layers (networks and fenestrated membranes) of the inner and middle coats. The tissue may be stained cautiously with dilute logwood solution, and glycerine afterwards added. The muscular cells are usable by their irregular outline and long rod-shaped nucleus. Sketch one or two and also a piece of fenestrated membrane. 4. Transverse section of aorta. Notice the differences in structure between this and the section of the smaller artery. 5. Transverse section of vena cava inferior. Notice the comparatively thin layer of circular muscle, and outside this the thick layer of longitudinal muscular bundles. Make sketches from 1, 4, and 5, under a low power, from 2 and 3 under a high power. An artery is usually described as being composed of three coats, an inner or elastic, a middle or muscular, and an external or areolar (fig. 109, b, c, d). It would, however, be more correct to describe the wall of an artery as being composed of muscular and elastic tissue lined internally by a pavement-epithelium and strengthened externally by a layer of connective tissue. For the present, however, we may adhere to the generally received mode of description. The inner coat of an artery is composed of two principal layers. The inner one is a thin layer of pavement-epithelium I often spoken of as the endothelium i. the cells of which are somewhat elongated in the direction of the axis of the vessel (fig. 110), and form a smooth lining to the tube. After death they become easily detached. Next to this comes an elastic 88 THE ESSENTIALS OF HISTOLOGY layer in the form either of elastic networks or of a fenestrated mem- wane. In some arteries there is a layer of fine connective tissue in- tervening between the epithelium and the fenestrated membrane (sub- ejntlielial layer). i*~ : Fig. 109. — Transverse section of part of the wall of the posterior tibial artery. (75 diameters.) a, epithelial and subepithelial layers of inner coat ; 5, elastic layer (fenestrated membrane) of inner coat, appearing as a bright line in section ; c, muscular layer (middle coat) ; d, outer coat, consisting of connective-tissue bundles. In the interstices of the bundles are some connective-tissue nuclei, and, especially near the muscular coat, a number of elastic fibres cut across. Fig. 110. — Epithelial layer lining the posterior tibial artery. (250 diameters.) Fig. 111. — Portion of fenestra- ted membrane from an artery. (Toldt.) «. b, c, perforations. The middle coat consists mainly of circularly disposed plain mus- cular fibres, but it is also pervaded in most arteries by a network of elastic fibres which are connected with the fenestrated membrane of the inner coat and are sometimes almost as much developed as the muscular tissue itself. This is especially the case with the larger arteries such as the carotid and its immediate branches, but in the smaller arteries of the limbs the middle coat is almost purely composed of muscular tissue. STRUCTURE OF THE LARGER BLOOD-VESSELS 89 The outer coat is formed of connective tissue with a good mam- elastic fibres, especially next the middle coat. The strength of an artery depends largely upon this coat ; it is far less easily cut or torn than the other coats, and it serves to resist undue expansion of the Fig. 112. — Elastic net- work OF ARTERY. (Toldt.) Fig. 1 13. — Muscular fibre-cells from superior thyroid artery. (340 diameters.) Fig. 114. — Section of thoracic aorta as sei n inhkii a low power. (Toldt.) a, the inner coat consisting of three layers, viz. : 1. Epithelium seen a? a fine line. 2. Sub- epithelial. 3. Elastic layers. In tin- part of the inner coat, at its junction with the middle, a layer of longitudinal muscular fibres i- represented as cut aero--, b, middle coat with its elastic membranes ; c, outer coat with two va-a vasorum. vessel. Its outer limit is not sharply marked, for it tends to blend with the surrounding connective tissue (hence it has been termed tunica adventitia). Variations in structure. — The aorta (fig. 114 1 differs in some 90 TPIE ESSENTIALS OF HISTOLOGY respects in structure from an ordinary artery. Its inner coat contains a considerable thickness of sub-epithelial connective tissue, but its clastic layers are chiefly composed of fine fibres, and are not especially marked off from those of the middle coat, so that the inner and middle coats appear almost blended with one another. On the other hand, there is a very great development of elastic tissue in the middle coat, this tissue forming membranous layers which alternate with layers of the mus- cular tissue. A good deal of connective tissue also takes part in the formation of the middle coat, so that the wall is unusually strong. The inner and middle coats constitute almost the entire thickness of the wall, the outer coat being relatively thin. The other variations which occur in the arterial system chiefly have reference to the development and arrangement of the muscular tissue. Thus in many of the larger arteries there are longitudinal muscular fibres at the inner boundary of the middle coat, and in some arteries amongst the circular fibres of the middle coat. This is the case in the aorta. In some parts of the umbilical arteries there is a com- plete layer of longitudinal fibres internal to the circular fibres and another external to them, whilst the amount of elastic tissue is very small. Longitudinal fibres are also present in some other arteries (iliac, superior mesenteric, splenic, renal, &c), external to the circular fibres, and therefore in the outer coat of the artery. The larger arteries themselves receive blood-vessels, vasa vasorum, which ramify chiefly in the external coat. Nerves, derived for the most part from the sympathetic system, are distributed to the muscular tissue of the middle coat. The veins (fig. 115) on the whole resemble the arteries in structure, but they present certain differences. In the internal coat the same £^*> %*g&8%$£g^ Fig. 115. — Transverse section of part of the wall of one of the posterior TIIilAL VEINS (MAN). a, epithelial and sub-epithelial layers of inner coat ; b, elastic layers of inner coat : c, middle coat consisting of irregular layers of muscular tissue, alternating with connective tissue and passing somewhat gradually into the outer connective tissue and elastic coat, d. layers may be present, but the elastic tissue is less developed and seldom takes the form of a complete membrane. The epithelium -cells are less elongated than those of the arteries. The middle coat (c) contains less elastic tissue and also less muscular tissue, being partly occupied by bundles of white connective-tissue fibres. These are derived STRUCTURE OF THE LARGER BLOOD-VESSELS 91 from the external coat, which is relatively better developed in the veins than in the arteries, so that, although thinner, their walls are often stronger. Many of the veins are provided with valves, which are semilunar folds of the internal coat strengthened by a little fibrous tissue : a few muscular fibres may be found in the valve near its attachment. The layer of the inner coat is rather thicker, and the epithelium-cells are more elongated on the side which is subject to friction from the current of blood than on that which is turned towards the wall of the vessel. Variations in different veins. — The veins vary in structure more than do the arteries. In many veins longitudinal muscular fibres are found in the inner part of the middle coat, as in the iliac, femoral, umbilical, &c. ; in others they occur external to the circularly disposed fibres, and are described as belonging to the outer coat. This is the case in the inferior vena cava and also in the hepatic veins and in the portal vein and its tributaries. In the superior and in the upper part of the inferior vena cava the circular fibres of the middle coat are almost entirely absent. The veins of the following parts have no muscular tissue, viz. pia mater, brain and spinal cord, retina, bones, and the venous sinuses of the dura mater and placenta. It is only the larger veins and especially those of the limbs that possess valves. They are wanting in most of the veins of the viscera, in those within the cranium and vertebral canal, in the veins of the bones, and in the umbilical vein. 92 THE ESSENTIALS OF HISTOLOGY LESSON XXI. SMALLER BLOOD-VESSELS. LYMPHATIC SYSTEM. 1. Take a piece of pia niater which has been stained with logwood, and separate from it some of the sntall blood-vessels of which it is chiefly composed. Mount the shreds in Farrant. The structure of the small arteries can be studied in this preparation, the nuclei of the epithelium and of the muscular coat being brought distinctly into view by the logwood. The veins, however, possess no muscular tissue. Capillary vessels which have been dragged out from the brain in removing the pia mater may also be seen in this preparation. Sketch two smaU arteries of different sizes, giving also their measurements. 2. Mount in Canada balsam a piece of the omentum of the rabbit stained with silver nitrate. The membrane should be stretched over a cork or a plate of glass, rinsed with distilled water, treated for five minutes with 1 per cent, nitrate of silver solution, again washed and exposed to the light in spirit. "When stained brown the spirit is replaced by oil of cloves. Pieces may now be cut off from the membrane and mounted, as directed, in Canada balsam ; they should include one or more blood-vessels. This preparation is intended to show the epithelium of the smaller blood- vessels and accompanying lymphatics and also the epithelium of the serous membrane. Sketch a small piece showing the epithelium of the vessels. 3. Mount in Canada balsam a piece of the central tendon of the rabbit's diaphragm which has been similarly prepared (except that the pleural surface has first been brushed to remove the superficial epithelium so as to enable the nitrate of silver more readily to penetrate to the network of lymphatic vessels underlying that surface). Observe the lymphatic plexus under a low power : sketch a portion of the network. If the peritoneal surface is focussed, the epithelium which covers that surface will be seen, and opposite the clefts between the radially disposed tendon-bundles stomata may be looked for in this epithelium. 4. Carefully study the circulation of the blood either in the web of the frog"s foot or in the mesentery or tongue of the frog or toad, or in the tail of the tadpole. The coats of the smaller arteries and veins are much simpler in structure than those of the larger vessels, but they contain at first all the same elements. Thus there is a lining epithelium and an elastic layer forming an inner coat, a middle coat of circularly disposed plain muscular tissue, and a thin outer coat. The same differences also are found between the arteries and veins, the walls of the veins being thinner and containing far less muscular tissue (fig. 116), and the lining epithelium-cells, much elongated in both vessels, are far longer SMALLER BLOOD-VESSELS 93 and narrower in the small arteries than in the corresponding veins (fig. 117). In the smallest vessels it will be found that the elastic layer has dis- appeared in the veins, and the muscular tissue is considerably reduced in thickness in both kinds of vessels. Indeed, it is soon represented by but a single layer of contractile cells, and even these no longer form a complete layer. By this time also, the outer coat and the elastic layer of the inner coat have entirely disappeared both from arteries and veins. The vessels are reduced, therefore, to the condition of a tube formed of pavement epithelium cells, with a partial covering of circularly disposed muscular cells. Even in the smallest vessels, which are not capillaries, the differ- c A b cd a b /. . & nil Js^Sl \\\ m£Zr~~'! \ *'^ Fig. 116. — A small artery. A, with a corresponding vein, B, treated with ACETIC acid. (, Magnified o50 diameters.) a, external coat with elongated nuclei : b, nuclei of the transverse muscular tissue of the middle coat < when seen endwise, a~ at the sides of the vessel, their outline is circular* ; c, nuclei of the epithelium-cells ; d, elastic layers of the inner coat. ences between arteries and veins are still manifested. These differences may be enumerated as follows : — The veins are larger than the corre- sponding arteries ; they branch at less acute angles ; their muscular cells are fewer, and their epithelium-cells less elongated ; the elastic layer of the inner coat is always less marked, and sooner disappears. Capillary vessels. — When traced to their smallest branches, the arteries and veins eventually are seen to be continued into a network of the smallest blood-vessels or capillaries. The walls of these are composed only of flattened epithelium-cells (fig. 118) continuous with those that line the arteries and vein? : these cells can be exhibited by staining a tissue with nitrate of silver. The capillaries vary somewhat in size and in the closeness of their meshes ; their arrangement in 94 THE ESSENTIALS OF HISTOLOGY different parts, which is mainly determined by the disposition of the tissue-elements, may best be studied when the structure of the several organs is considered. In the transparent parts of animals, the blood may be seen flowing through the capillary network froni the arteries into the veins. The Fig. 117.— A small artery, A, a»d vein, V, from the subcutaneous connective TISSUE OF THE RAT, TREATED WITH NITRATE OF SILVER. (175 diameters.) a, a. epitheloid cells with b, h, their nuclei : m, m, transverse markings due to staining of substance between the muscular fibre-cells; c, c, nuclei of connective-tissue corpuscles attached to exterior of vessel. current is very rapid in the small arteries, somewhat less so in the veins, and comparatively slow in the capillaries. The current is fastest in the centre of the vessel, slowest near the wall (inert layer), and with care it may be observed— especially where there is any commen- cing inflammation of the part, as in the mesentery in consequence of CAPILLARY BLOOD-VESSELS AXD LYMPHATICS 95 exposure — that the white blood-corpuscles, which always tend to pass into the inert layer, and to adhere occasionally to the inner sur- Fig. 118. — Capillary Vessels from the bladder of the cat, mag- The outlines of the cells are stained by nitrate of silver. Fig. 110. — Capillary blood- vessels IN THE AVEB OF A FROG'S FOOT, AS SEEN WITH THE MICROSCOPE. The arrows indicate the course of the blood. face of the blood-vessels, here and there pass through the coats of the small vessels, and appear as migratory cells in the surrounding connective tissue. LYMPHATIC SYSTEM. To the lymphatic system belong not only the lymphatic vessels and lymphatic glands, but also the cavities of the serous membrane*, which are moistened with lymph and are in open communication with the lymphatic vessels in their parietes. The larger lymphatic vessels somewhat resemble the veins in Structure, except that their coats are much thinner and their valves much more numerous. In lymphatics of somewhat smaller size, the wall of the vessel is formed, first, by a lining of pavement-epithelium cells (endothelium of some authors), which are elongated in the direc- tion of the axis of the vessel ; and, secondly, by a layer of circularly and obliquelv disposed muscular fibres. In the smallest vessels (lymphatic capillaries), which, however, are generally considerably larger than the blood-capillaries, there is nothing but the epithelium remaining, and the cells of this are frequently not more elongated in one direction than in another, but have a characteristic wavy outline (fig. 121). Lymphatics begin in two ways — either in the form of plexuses, as in membranes (fig. 120), or as lacunar interstices, as is the case in some of the viscera. 96 THE ESSENTIALS OF HISTOLOGY In order to show the lymphatic vessels, it is generally necessary to stain a tissue with nitrate of silver ; but they may easily be in- jected by sticking the nozzle of an injecting canula into any tissue which contains them, and forcing coloured fluid under gentle pressure into the interstices of the tissue. KTOMW 1 Fig. 120. — Lymphatic plexus of central tendon of diaphragm of rabbit, pleural side. o, laxger vessels with lanceolate cells and numerous valves ; 6, c, lymphatic capillaries with wavy -bordered cells. In silvered preparations it may be observed that the lymphatics always appear in the form of clear channels in the stained ground-sub- LYMPHATIC VESSELS 97 Fig. 1*21. — A small part of the lymphatic plexus on the pleural surface of the diaphragm. (Magnified 110 diameters.) (Ranvier.) L, lymphatic vessel with characteristic epithelium; c, cell-spaces of the connective tissue, here and there abutting against the lymphatic. Fig. 122. — Small portion of peritoneal surface of diaphragm of rarp.it, stained with nituaii "i mi.vi'.i: to show the serous epithelium. I, lymph-channel below the surface, lying between tendon bundles, t,t, and over which the surface-cells are seen to be relatively smaller, and to exhibit I into the lymphatic. The epithelium of the lymphatic channel is not represented. 98 THE ESSENTIALS OF HISTOLOGY stance of the connective tissue, and that their walls are in close con- nection with the cells and cell- spaces of that tissue. But, except in the case of the serous membranes, there is no open communication between the lymphatic vessels and the interstices (areola?) of the con- nective tissue. Development of the blood-vessels and lymphatics. — The blood- vessels and lymphatics are developed in the connective tissue or in the mesoblastic tissue which precedes it, the first vessels being formed in the vascular area which surrounds the early embryo. Both kinds of vessels are developed from cells | vasoformative cells) which become hollowed out by an accumulation of fluid in their protoplasm, and in the case of developing blood-vessels coloured blood-corpuscles may also be formed within these cells I see Development of Blood-corpuscles, Lesson II.) The cells branch and unite with one another to form a network, and their cavities extend into the branches. In the mean- time their nuclei multiply and become distributed along the branches, cell-areas being subsequently marked out around them. In this way intercommunicating vessels— capillaries containing blood or lymph — are produced (fig. 123 j. These presently become connected with Fig. 123. — Isolated capillary network formed by the junction ov several hollowed-out cells, and containing coloured blood-cor- puscles in a clear fluid. c, a hollow cell the cavity of which does not yet communicate with the network ; p, p, pointed cell-processes, extending in different directions for union with neighbouring capillaries. previously formed vessels, which extend themselves by sending out sprouts, at first solid, and afterwards hollowed out. It is not precisely known whether the larger blood-vessels and lymphatics are developed at first as capillaries, the muscular and other tissues being subsequently added, or whether they are formed as clefts in the mesoblastic tissue which become bounded by flattened cells. The serous membranes, which may conveniently be studied in con- nection with the lymphatic system, are delicate membranes of connec- tive tissue which surround and line the internal cavities of the body, and are reflected over many of the thoracic and abdominal viscera ; in SEROUS AND SYNOVIAL MEMBRANES 99 passing to which they form folds, within which blood-vessels, lymphatics, and nerves pass to the viscera. The inner surface is lined by a continuous layer of pavement- epithelium (fig. 122 1, which is very distinct in nitrate of silver prepa- rations. In some places there are apertures in the epithelium which lead direct into subjacent lymphatic vessels. These apertures are called stomata, and are surrounded by small protoplasmic cells ifig. 122, s, s). They are most numerous upon the peritoneal surface of the diaphragm, but are present in all serous membranes, and they serve to prevent any undue accumulation of lymph within the serous cavity during health. The pavement-epithelium rests upon a homogeneous basement-mem- brane, which is especially well marked in the serous membranes of man. The rest of the thickness of the membrane is composed of con- nective tissue, with a network of fine elastic fibres near the inner surface. The cavities of the serous membranes are originally formed in the embryo as a cleft in the mesoblast ipleuro-peritoneal split i which becomes lined with epithelium, and its wall eventually becomes dif- ferentiated into the serous membrane. The synovial membranes, which are often compared with the serous membranes, and are indeed, like the latter, connective-tissue membranes which bound closed cavities moistened with fluid, are not so intimately connected with the lymphatic system, nor is the fluid (synovia) which moistens them of the nature of lymph. Moreover, it is only here and there that there is a lining of epithelmm-like cells, in place of the continuous lining of epithelium which we find in the serous membranes. Curious villus-like projections occur in many parts ; they are covered by small rounded cells, and probably serve to extend the surface for the secretion of synovia. The blood-vessels of synovial membranes are numerous, and approach close to the inner surface of the membrane. B2 100 THE ESSENTIALS OF HISTOLOGY LESSON XXII. LYMPHATIC GLANDS, TONSIL, THYMUS. 1. Sections of a lymphatic gland which has been stained in bulk with magenta and embedded in paraffin. 1 Notice (1) the fibrous and muscular capsule, with trabecidae extending inwards from it through the cortex and anastomosing with one another in the medulla, (2) the dense lymphoid tissue (adenoid tissue of authors) forming large masses in the cortex (cortical nodules I and rounded cords in the medulla (medullary cords). Notice also the clearer channel or lymph -sinus which everywhere intervenes between the fibrous tissue and the lymphoid tissue. Observe the fine fibres and branched cells which bridge across this channel. Make a general sketch under a low power of a portion of the cortex together with the adjoining part of the medulla, and under a high power drawings of small portions of cortex and medulla. 2. In sections of tonsil prepared similarly to those of the lymphatic gland, notice the large amount of lymphoid tissue only imperfectly collected into nodules. Observe also that the stratified epithelium, which covers the mucous membrane here as elsewhere in the mouth, is infiltrated with lymph-cor- puscles. Here and there pit-like recesses may be met with glands opening into the pits. 3. A similar preparation of the thymus gland of an infant. Notice that the masses of lymphoid tissue which form the lobules of the gland are separated by septa of connective tissue, and that they show a distinction into two parts, cortical and medullary. Observe the differences of structure of these two parts, and especially notice the concentric corpuscles in the medullary part. Make a sketch of one of the lobules under a low power and of a small part of the medulla under a high power, including one or two concentric corpuscles. Measure the latter. Structure of a lymphatic gland. — A lymphatic gland is composed of a, fibrous and muscular framework, which encloses and supports the proper glandular substance, but is everywhere separated from it by a narrow channel, bridged across by cells and fibres, which is known as the lymph-channel. The framework consists of an envelope or capsule (fig. 124, c), and of trabecules (tr), which pass at intervals inwards from the capsule, and after traversing the cortex of the gland divide and reunite with one another so as to form a network of fibrous bands. At one part of the gland there is usually a depression (hilus), and at the bottom of this the medulla comes to the surface and its fibrous bands are directly continuous with the capsule. 1 See Appendix. LYMPHATIC GLANDS 101 Fig. 124. — Diagrammatic section of lymphatic gland. a. I. afferent, e. I. efferent lymphatics ; C, conical substance ; M. reticulating cords of medullary sal 'stance ; l.s. lymph-sinus ; c, fibrous coat sending trabecular tr, into the substance of the gland. Fig. 125. — Sectiob of the medullary substance of a lymphatic glass (ox). (300 diameter-. | a, a, a, lymphoid cords ; c, lymph-sinus ; 6, 6, trabecule ; d, d, capillary blood-vessels. 102 THE ESSENTIALS OF HISTOLOGY The proper glandular substance (/. h.) is composed of lymphoid tissue, i.e. a fine reticulum with the meshes thickly occupied by lymph- corpuscles. It occupies all the interstices of the gland, forming com- paratively large rounded masses in the cortex i lymphoid nodules. G) between the trabecular and smaller reticulating cord-like masses (lymphoid cords. M) in the medulla. The cells which bridge across the lymph-channel in the medulla (fig. 125, c) are branching nucleated cells which often contain pigment, so that this part of the gland has a dark colour. The lymph-channel is bridged across not only by these, but also by fibres derived from the capsule and trabecular, which pass to the lymphoid tissue and become lost in its reticulum. But these fibres are often covered and concealed by the branched cells. Lymphatic vessels (fig. 124, a. I.) enter the lymph-channels after passing through the capsule, and the lymph is conveyed slowly along the channels of the cortical and medullary part towards the hilus, taking up many lymph-corpuscles in its passage. At the hilus it is gathered up by an efferent vessel or vessels [e. I.) which take origin in the lyrnph- sinuses of the medulla. An artery passes into each gland at the hilus ; its branches are conveyed at first along the fibrous cords, but soon pass into the lymphoid tissue, where they break up into capillaries (fig. 125, d). The blood is returned by small veins, which are conducted along the fibrous trabecular to the hilus again. Fig. 126. — A lobule of the thymus <>f a child as seen under a low power. c, cortex ; m, medulla ; c, concentric corpuscles ; 6, blood-vessels ; tr, trabecules. The thymus gdand is a lymphoid organ which is found only in the embryo and during infancy. It is composed of a number of larger and smaller lobules (fig. 12(3 1, which are separated from one another by THYMUS GLAND 103 septa of connective tissue, along which the blood-vessels and lymphatics pass to and from the lobules. Each lobule shows plainly, when examined with the low power, a distinction into an outer cortical and an inner medullary portion. The cortical part of the lobule is imper- fectly divided into nodules by trabecular of connective tissue, and is very similar in structure to the lymphoid tissue of the lymphatic glands and tonsils, but the medulla is more open in its texture, and the reticulum is composed of larger, more transparent, flattened cells, and contains fewer lymph-corpuscles. Moreover, there are found in -;^ « Fig. 127. — Elements of the thtmcs. (300 diameters.) (Cadiat.) a, lymph-corpuscles ; 6, concentric corpuscle. the medulla peculiar concentrically striated bodies (the concentric cor- puscles, fig. 127), which are usually composed of a number of flattened cells arranged concentrically around one or more central cells. Some- times these corpuscles are compound, two or three being grouped together and similarly enclosed by flattened cells. The lymphoid tissue is abundantly supplied with capillary blood-vessels, and large lymphatic vessels issue from the organ, but in what way the latter are connected with the lobules has not been ascertained. Lymphoid tissue occurs in many other parts of the body in addition to the lymphatic glands, tonsils, and thymus gland, although it may not, as in these structures, constitute the bulk of the organ. Thus it is found in many mucous membranes, such as those of the intestine and of the respiratory tract, both in a diffuse form and also collected into nodular masses which are like the cortical nodules of a lymphatic gland, and may, like those, be partially surrounded by a lymph-sinus. In the spleen also a large amount of lymphoid tissue is found sheathing tin -mailer arteries, and also expanded into nodular masses (Malpighian corpuscles of the spleen). In these organs it will, however, be studied in subsequent Lessons. Lymphoid tissue also occurs in considerable amount in the serous membranes, especially in young animals ; in the adult it is often trans- formed into adipose tissue. The tissue is generally developed in con- nection with lymphatic vessels, an accumulation of retiform tissue and lymph-cells taking place either external to and around the lymphatic 104 THE ESSENTIALS OF HISTOLOGY (perilymphatic nodule) ; or the lymphatic is dilated into a sinus and Fig. 128. — Developing lymphatic nodules, from the omentum of a guinea- pig. A, perilymphatic nodule ; a, lymphatic vessel ; c, part of its epithelial wall, seen in optical section ; e, lymph-corpuscles within the vessel ; b, lymphoid tissue of the nodule ; d, blood- capillaries ; *B, endolymphatic nodule ; a, vein ; 6, artery ; c, capillaries ; d, a lymphatic vessel, in which this whole system of blood-vessels is enclosed ; e, lymphoid tissue within the lymphatic vessel ; /, wall of the lymphatic in optical section. the formation of lymphoid tissue occurs within it (endolymphatic nodule) (see fig. 128). 105 LESSON XXIII. THE SKIN. 1. Sections of skin from the palmar surface of the fingers. The sections are to be made vertical to the surface, and should extend down as far as the subcutaneous tissue. They may be stained with logwood or picro-carmme and mounted in Canada balsam. In these sections notice the layers of the epidermis and their different behaviour to the staining fluid. Notice also the papillae projecting from the coriuin into the epidermis, and look for tactile corpuscles within them. In very thin parts of the sections the fine inter- cellular channels in the deeper parts of the epithelium (see Lesson VI. p. 22) may be seen with a high power. The convoluted tubes of the sweat-glands will be seen here and there in the deeper jiarts of the corium, and in thick sections the corkscrew-like channels by which the sweat is conducted through the epidermis may also be observed. Make a sketch showing the general structure tmder a low power, and other sketches to exhibit the most important details under a high power. Measure the thickness of the epidermis and the length of the papillae. 2. Sections of the skin of the scalp, vertical to the surface and parallel to the slope of the hair-follicles, and others parallel to the surface, and therefore across the hair-follicles. Stain and mount in the same way as in the last preparation. Examine also the structure of the hairs. In these preparations the details of structure of the hairs and hair-follicles together with the sebaceous glands and the little muscles of the hair-follicles are to be made out. 3. Vertical sections across the nail and nail-bed, cut with a strong scalpel or razor. The sections are stained with hematoxylin or picro-cannine. Notice the ridges (not papillae) of the corium projecting into the epidermis. Observe also the distinction of the epidermis into Malpighian layer and nail proper. 4. Mount in Canada balsam a section from a portion of skin of which the blood-vessels have been injected, and notice the distribution of the capillaries to the sweat-glands, to the hair-follicles, and to the papillary surface of the corium. The skin is composed of two parts, epidermis and cutis vera. The epidermis, or scarf skin, is a stratified epithelium (fig. 120). It is composed of a number of layers of cells, the deeper of which are soft and protoplasmic, and form the rete mucosum of Malpighi, whilst the superficial layers are hard and horny ; this horny portion some- times constituting the greater part of the thickness of the epidermis. The deepest cells of the rctc mucosum. which are set on the surface of the cutis vera, are columnar (fig. 129, c) in shape. In the coloured 106 THE ESSENTIALS OF HISTOLOGY races of mankind these cells contain pigment-granules. In the layers immediately above them the cells are polyhedral (fig. 129, p). Between all these cells of the rete mucosum there are fine intercellular clefts which separate the cells from one another, but are bridged across by fine fibres, which pass from ceU to cell. The intercellular channels serve for the passage of lymph, and within them occasional lymph- corpuscles may be found, often having a stellate figure from compres- sion. The most superficial layer of the rete mucosum is formed of somewhat flattened granular cells [stratum granulosum, S.gr). Im- MJ ' /.',' ■■: ■'&\ rw n Fig. 129. — Section of epidermis. H, horny layer, consisting of s, superficial horny scales ; sir, swollen-out horny cells ; s.l. stratum lucidum ; M, rete mucosum or Malpighian layer, consisting of p, prickle-cells, several rows deep : c, elongated cells forming a >ingle stratum near the corium : and t.gr. stratum granulosum of Langerhans, just below the stratum lucidum ; n, part of a plexus of nerve-fibres in the superficial layer of the cutis vera. From this plexus fine varicose nerve-fibrils may be traced passing up between the epithelium-cells of the Malpighian layer. mediately above this layer, the horny part of the epidermis commences, as a layer of clear compressed cells several deep (stratum lucidum, s.l.). Above this comes the main part of the horny layer. It is composed of a number of layers of somewhat swollen cells (sit).), the nuclei of which are no longer visible. These cells become flatter as they approach the surface, where they eventually become detached in the form of thin horny scales (s). The growth of the epidermis takes place by a multiplication of the THE SKIN 107 cells of the deeper layers. The newly formed cells, as they grow, push towards the surface those which were previously formed, and in then- progress the latter undergo a chemical transformation, which converts their protoplasm into horny material. This change seems to occur at the stratum granulosum (see fig. 130) ; the granules which occupy the cells of that layer being composed of a substance termed eleidin, which is transformed into keratin. No blood-vessels pass into the epidermis, but it receives nerves which ramify between the cells of the rete mucosiun in the form of fine varicose fibrils (fig. 129). , W^e Fig. 130. — Portion <>i epidermis from a section of the skin of the FINGER, COLOURED WITH PICROCARMINATE OF AMMONIA. (Kanvier.) a, stratum corneum ; 6, stratum lucMum with diffused flakes of eleidin ; c, stratum grauu- losum, the cells tilled with drops of eleidin; d, prickle-cells; e, dentate projections by which the deepest cells of the epidermis are fixed to the cutis vera. The cutis vera or corium is composed of dense connective tissue, which becomes more open and reticular in its texture in its deeper part, where it merges into the subcutaneous tissue. The superficial or vascular layer of the corium bears minute papilla, which project up into the epidermis, which is moulded over them. These papillae for the most part contain looped capillary vessels (fig. 137), but some, especially those of the palmar surface of the hand and fingers, and the corresponding part of the foot, contain tactile corpuscles, to which medullated nerve-fibres pass (fig. 97, b). In some parts of the body (scrotum, penis, nipple, and areola), involuntary muscular tissue occurs in the deeper portions of the cutis vera, and in addition, wherever hairs occur, small bundles of this tissue are attached to the hair-follicles. The blood-vessels of the skin are distributed almost entirely to the surface, where they form a close capillary network, sending up loops 108 THE ESSENTIALS OF HISTOLOGY into the papillae. Special branches are also distributed to the various appendages of the skin, viz. the sweat-glands and hair-follicles, with their sebaceous glands and little muscles, as well as to the little masses of adipose tissue which may be found in the deeper parts of the cutis. The lymphatics originate near the surface in a network of vessels, which is placed a little deeper than the blood-capillary network. They receive branches from the papilla?, and pass into larger vessels, which are valved. and which run in the deeper or reticular part of the corium. From these the lymph is carried away by still larger vessels, which course in the subcutaneous tissue. The appendages of the skin are the nails, the hairs, with their sebaceous glands and the sweat-glands. They are all developed as thickenings and downgrowths of the Malpighian laver of the epi- dermis. Fig. 131. — Section across the nail and nail-bed. (100 diameters.) (Heitzmann.) P, ridges with blood-vessels ; B, rete mucosum ; N, nail. The nails are thickenings of the stratum lucidum of the epidermis, which are developed over a specially modified portion of the corium, which is known as the bed of the nail, the depression at the posterior part of the nail-bed from which the root of the nail grows being known as the nail-groove. The distal part of the nail forms the free border, and is the thickest part of the body of the nail. The horny substance of the nail (fig. 131, N) is composed of clear horny cells, each containing the remains of a nucleus ; it rests immediately upon a Malpighian layer (B) similar to that which is found in the epidermis THE SKIN 109 generally. The coriurn of the nail-bed is beset with longitudinal ridges instead of the papillae which are present over the rest of the skin ; these, like the rest of the superficial part of the corium, are extremely vascular. The nails are developed in the foetus at about the third month, the groove being formed at this time in the corium, and the nail-rudiment appearing in it as a thickening of the stratum lucidum, which extends forward over the bed. It becomes free in the sixth month, its free end being at first thin, but as it grows forward over the bed it appears to receive additions on its under surface, so that after a time the distal part becomes the thicker. The superficial layers of the cuticle which originally covered the developing nail become detached, and, after birth, only remain as the narrow border of cuticle which overlies the lunula. The hairs are growths of the epidermis, which are developed in little pits — the hair-follicle* — which extend downwards into the deeper part of the corium, or even into the subcutaneous tissue. The hair grows from the bottom of the follicle, the part which thus lies within the follicle being known as the root. The substance of a hair is mainly composed of a pigmented, horny, fibrous material (fig. 132,/), which can be separated by the action of sulphuric acid into long tapering cells, the nuclei of which are still visible. This fibrous substance of the hair is covered by a layer of delicate imbricated scales termed the ha ir-cuticle I c ) . In many hairs, but not in all, the centre is occupied by a dark-looking axial substance ( medulla, m), formed of angular cells which contain granules of eleidin, particles of dark pigment, and frequently minute air-bubbles. The latter may also occur in interstices in the fibrous substance. When they are present, the hair looks white by reflected light. The root has the same structure as the body of the hair, except at its extremity, which is enlarged into a knob (fig. 133, b) ; this is composed mainly of soft, growing cells, and fits over a vascular papilla (p), which pro- jects up into the bottom of the follicle. The follicle, like the skin itself, of which it is a recess, is composed of two parts : one epithelial, and the other connective tissue. The epithelial or epidermic part of the follicle closely invests the hair-root, and is often in great part dragged out with it ; hence it is known as the root-sheath. It consists of an outer layer of soft columnar and polyhedral cells, like the Mal- pighian layer of the epidermis — the outer root-sheath (figs. 133,/; L84, e) : and of an inner, thinner, horny stratum next the hair — the inner root-sheath (figs. 133, g ; 134,/). The inner root-sheath itself consists of three layers, the outermost being composed of oblong cells without nuclei iHenle's layer), the next of flattened polyhedral nu- cleated cells [Huxley's layer), and the third — the cuticle of the root- sheath — being a thin layer of downwardly imbricated scales, which fit over the upwardly imbricated scales of the hair itself. The connective tissue or dermic part of the hair-follicle (fig. 134, a, c, d) is composed internally of a vascular layer, separated from the 110 THE ESSENTIALS OF HISTOLOGY Fig. 132.— Piece of human hair. (Magnified.) A, seen from, the surface ; B, in optical section, c, cuticle ; /, fibrous substance : m, medulla, the air having been expelled'by Canada balsam. Fig. 134.— Section <>f hair- FOLLIlLK. I, dermic coat of follicle ; 2, epi- dermic coat or root-sheath : ". outer layer of dermic coat, with blood-vessels, b. l. cut acn middle layer : d. inner or hyaline layer; e, outer root-sheath; /, u, inner root-sheatb : ft, cuticle of root -sheath ; I, hair. Fig. 133. — Hair-follicle in longitudinal SECTION. a, mouth of follicle : h. neck ; c. hulb : d. e, dermic : /. outer root-sheath ; ;/, inner root -sheath ; ft, hair; /., its medulla ; I, hair-knob ; »i, w tissue; ». hair-muscle: o. papilla of skin: p, papilla of hair : s, rete mucosum, continuous with outer root-sheath ; ep, horny layer ; /, sebaceous gland. THE SKIN 111 root-sheath by a basement -membrane termed the follicle. This inner vascular layer corresponds to of the cutis vera. Its fibres and cells have a regular circular arrangement around the follicle, the cells being flattened against the hyaline layer. Externally the dermic coat of the follicle has a more open texture, corresponding to the reti- cular part of the cutis, and containing the larger branches of the arteries and veins. In the large tactile hairs of animals, the veins near the bottom of the follicle are dilated into sinuses, so as to pro- duce a kind of erectile structure. The hair grows from the bottom of the follicle by multiplication of the soft cells which cover the papilla, these cells becoming elongated to form the fibres of the fibrous substance, and otherwise modi- fied to produce the medulla and cuticle. When a hair is eradicated, a new hair is pro- duced from these cells. It is not uncommon to find hair-follicles in which the whole of the lower part has degenerated in such a way that the vascular papilla, and the soft, growing cells which cover it, may have entirely disappeared. The hair then ceases to grow, and eventually becomes lost, but its place may be again supplied by a new hair, which becomes formed in a downgrowth from either the bottom or the side of the hair-follicle, a new papilla first becoming formed at the extremity of the downgrowth ifig. 135 1. If not previously detached, the old hair may be pushed from out the follicle by the one which replaces it. The hairs are originally developed in the embryo in the form of small solid down growths from the Malpighian layer of the epidermis (fig. 180, A). The hair-rudiment, as it is called, is at first com- 1 entirely of soft, growing cells ; but presently those in the centre become differentiated, so as to produce a minute hair invested by inner root- th, and its base resting upon a papilla which ha- grown up into the extremity of the hair-rudi- ni. m from the corium (fig. 13G, Bi. As the minute hair grows, it pushes its way through the superficial layers of the epidermis, which it finally perforates (Cj. The hair-rudiments commence at the third or fourth month of fatal life : their growth is completed about the fifth or sixth month, and they form a complete hairy covering hyaline layer of the the superficial layer I"l'.. 135. — COMMEK- ( IVi, Bl I'l.A' I Ml NT OF OLD BV SEW HAIB. (Toldt.) o, out ith; b. den: Hide : /, downgrowth of epi- thelium ;.. form ii''A hair-follicle : ;•. papilla of new hair commen- cing : I hair; t. .-eous gland. 112 THE ESSENTIALS OF HISTOLOGY termed the lanugo. This is entirely shed within a few months of birth, the new hairs being formed in downgrowths from the old hair-follicles in the manner already mentioned. Hairs grow at the rate of half an inch per month. They are found all over the body except on the palms of the hands and the soles of the feet, and on the distal phalanges of the fingers and toes. They Fig. 136. Hair-rudiment from an embryo of six weeks. «. horny, and 6, mucous or Malpighian layer of cuticle : i, basement-membrane ; m, cells, some of which are assuming an oblong figure, which chiefly form the future hair. B. Hair-rudiment, with the young hair formed but not yet risen through the cuticle, a, horny, 6. Malpighian layer of epidermis ; c, outer, d, inner, root-sheath ; e, hair-knob : /, stem, and ue layer ; c, elastic network : d, subserous areolar tissue ; e, fat ; /, section of a blood-vessel ; ■/. a small ganglion : h, muscular fibres of the myocardium ; i, intermuscular areolar tissue. The myocardium is covered externally by a layer of serous mem- brane — the epicardium (cardiac pericardium, fig. 141) — composed, like other serous membranes, of connective tissue and elastic fibres, the STRUCTURE OF THE HEART 117 latter being most numerous in its deeper parts. Underneath the epicardium run the blood-vessels, nerves, and lymphatic vessels of the heart, embedded in areolar and adipose tissue ; this tissue being con- tinuous with that which lies between the muscular bundles. The endocardium (fig. 142) has a structure not very unlike the pericardium. It is lined by a pavement -epithelium, like the epithelium of a serous membrane, and consists of connective tissue with elastic fibres in its deeper part, between which there may, in some parts, be Fig. 142. — Section of the endocar- dium OF THE EIGHT AURICLE. a, lining epithelium ; b, connective tissue with fine elastic fibres ; c, layer with coarser elastic fibres : J sub-endocardial connective tissue continuous with the intermuscular tissue of the myocardium ; A, muscular fibres of the myocardium : m, plain muscu- lar tissue in the endocardium. Fig. 143. — Section through oxe of the flaps of the aortic valve, and part <>i the corresponding six! s oi Valsalva, with the ad- JOINING PART OK THE VENTElCUbAR WALL. a, endocardium, prolonged over the valve; b, Bnb-endocardial tissue ; e, fibrous tissue of the valve, thickened at e' near the free edge ; "'. tion of the lunula; e, section of the fihrou- ring ; /', muscular fibres of the ven- tricle attached to it ; g, loose areolar tissue at the base of the ventricle ; s. I', sinus Valsilvie; 1, 2, 3, inner, middle, and outer coat- of the aorta. ■ found a few plain muscular fibres. Fat is sometimes met with under the endocardium. In some animals, e.g. the sheep, and sometimes also in man, large beaded fibres are found under the endocardium. These are formed of large clear cells joined end to end, and generally containing in their centre two nuclei, whilst the peripheral part of the cell is formed of cross- striated muscular tissue ; they are known as the fibres of Purkinje. The valves of the heart are formed of folds of the endocardium strengthened by fibrous tissue (fig. 113). This tissue forms a thicken- 118 THE ESSENTIALS OF HISTOLOGY ing near the free edge of the valve {&). At the base of the auriculo- ventricular valves a little of the muscular tissue of the auricle may be found passing a short distance into the valve. The nerves of the heart are seen in sections underneath the epi- cardium of both auricles and ventricles ; in the former situation, they are connected at intervals with small ganglia (fig. 141, g). Their branches pass to the muscular substance, but their mode of termina- tion has not been ascertained. 119 LESSON XXV. THE TRACHEA AXD LUNGS. 1. In sections of trachea, stained with logwood or borax-carmine, and mounted in Canada balsam, notice the ciliated epithelium, the basement-membrane lie thickness in the human tracheal, the lymphoid tissue of the mucous membrane, the elastic tissue external to this, and lastly the fibrous membrane containing the cartilages. In the mucous membrane and submucous areolar tissue look for sections of mucous glands, ducts of which may be seen opening on the surface. At the back of the trachea notice the plain muscular fibres transversely arranged ; there may be larger mucous glands external to these. 2. In sections of lung similarly prepared, notice the sections of the alveoli collected into groups (infundibula). Find sections of bronchial tubes, some cut longitudinally and passing at their extremities into the infundibula, others cut across ; the latter show the structure of the tubes best. In each tube notice the ciliated epithelium internally. Next to this the mucous membrane containing numerous elastic fibres and often thrown into folds ; then the layer of circular muscular fibres, and outside this, loose fibrous tissue in which in larger bronchial tubes the pieces of cartilage may be seen embedded. Small mucous glands may also be observed in the fibrous tissue sending their ducts through the other layers to open on the inner surface. Notice always accompanying a section of a bronchial tube the section of a branch of the pulmonary artery. In the sections of the alveoli observe the capillary vessels passing from one side to the other of the intervening septa ; and in places where the thin wall of an alveolus is to be seen in the section, try and make out the net- work of blood-capillaries upon it. Notice within the alveoli nucleated cor- - which very frequently contain dark particles in their protoplasm. They appear to be amoeboid cells which have migrated from the blood-vessels and have taken in inhaled particles of carbon. They seem to pass back into the lung tissue, for similar cells may be seen in this. Make a sketch of part of the wall of a bronchial tube and of one or two of the alveoli. 3. Mount in Canada balsam a section of lung in which the pulmonary vessels have been injected. Study the general arrangement of the vessels with a low power, and the network of capillaries of the alveoli with a high Observe that the veins run apart from the arteries. Sketch the capillary network of one or two adjoining alveoli. The trachea or windpipe is a fibrous and muscular tube, the wall of which is rendered somewhat rigid by Q-shaped hoops of cartilage which are embedded in the fibrous tissue. The muscular tissue, which is of the plain variety, forms a flat band, the fibres of which run trans- versely at the back of the tube. The trachea is lined by a mucous 120 THE ESSENTIALS OF HISTOLOGY membrane (fig. 144, a-c), which has a ciliated epithelium upon its inner surface. The epithelium-cells have been already described (Lesson VII.) ; they rest upon a thick basement-membrane. The mucous membrane proper consists of areolar and lymphoid tissue, and contains numerous blood-vessels and lymphatics. In its deepest part is a well-marked layer of longitudinal elastic fibres (d). Many small glands for the secretion of mucus are found in the wall of the trachea. They may lie either within the mucous membrane or in the submucous em4 --- ; ' Vv- mm? Fig. 144. — Longitudinal section of the human trachea, including portions of two cartilaginous rings. (Moderately magnified.) a, ciliated epithelium : b. basement-membrane ; c, superficial part of the mucous membrane, containing the sections of numerous capillary blood-vessels and much lymphoid tissue ; d, deeper part of the mucous membrane, consisting mainly of elastic fibres ; e. submucous areolar tissue, containing the larger blood-vessels, small mucous glands (their ducts and alveoli are seen in section ). fat. &c. :/. fibrous tissue investing and uniting the cartilages ; g, a small mass of adipose tissue in the fibrous layer ; A, cartilage. areolar tissue (e), or, lastly, at the back of the trachea, outside the transverse muscular fibres. The two divisions of the trachea, the bronchi, are precisely similar in structure. The larynx is also very like the trachea so far as the structure of the mucous membrane is concerned, but over the true vocal cords and upon the epiglottis, as well as here and there hi the part above the glottis, stratified epithelium is found, and taste-buds (see Lesson XXVI.) may occur in this epithelium, except over the vocal cords. THE TRACHEA AND LUNGS 121 The lymphoid tissue is especially abundant in the mucous mem- brane of the ventricle of Morgagni, and a large number of mucous glands open into this cavity and into that of the sacculus. The true vocal cords are composed of fine elastic fibres. The cartilages of the trachea and larynx are hyaline, except the epiglottis and the cartilages of Santorini and of Wrisberg, which are composed of elastic fibro-cartilage. Fig. 145. — Diagrammatic representation of the ending of a bronchial tube in sacculated lnfundibula. The lungs are formed by the ramifications of the bronchial tubes and their terminal expansions, which form groups of sacculated dila- tations {infundibula), beset everywhere with small hemispherical bulgings, known as the air-cells ox pulmonary alveoli. deb Fig. 146. — Portion of a trahsvkbse sectioh of a bronchial tube, human G mm. in diameter. (Magnified 30 diameters.) a, cartilage and fibrous layer with mucous sland=. and. in the outer part, a little fat ; in the middle, the duct of a eland opens on the inner surface of the tube; b, annular layer of involuntary muscular fibres : <\ elastic layer, the elastic fibres in bundles which are seen cut across ; d, columnar ciliated epithelium. The bronchial tubes (figs. 146, 147) are lined in their whole extent by ciliated epithelium which rests on a basement-membrane. External to this is the corium of the mucous membrane, containing a large number of longitudinal elastic fibres and some lymphoid tissue. 122 THE ESSENTIALS OF HISTOLOGY Outside this again is a complete layer of plain muscular fibres encircling the tube. Next comes a loose fibrous layer in which, in the larger tubes i fig. 146), small plates of cartilage are embedded. Mucous glands are also present hi this tissue. Fig. 147. — Section of a small bronchial tube from the pig's long. (This section is much more magnified than that represented in the previous figure.) a, fibrous layer : b, muscular layer : c, mucous membrane in longitudinal folds, with numer- ous longitudinally ruuuiug elastic fibres cut across ; d, ciliated epithelium ; /, surround- ing alveoli. The smallest bronchial tubes, which are about to expand into the infundibula, gradually lose the distinctness of the several layers, their wall at the same time being greatly thinned out and becoming bulged to form the alveoli. The epithelium also becomes changed ; from columnar and ciliated it becomes cubical and non-ciliated. In the alveoli themselves, besides small groups of cubical cells, there are large irregular flattened cells (fig. 148) which form an extremely delicate layer, separating the blood-capillaries from the air within the alveoli. The capillary network of the alveoli is very close (fig. 149), and the capillary vessels of adjoining alveoli are in complete continuity, the vessels passing first to one side and then to the other of the septa which separate the adjacent alveoli. Blood-vessels. — Branches of the pulmonary artery accompany the bronchial tubes to be distributed to the capillary networks upon the alveoli, from which the blood is returned by the pulmonary veins which, pursuing a separate course through the tissue of the lung, join in their course with others to form larger vessels which pass to the hilus. Branches from the bronchial arteries are distributed to the walls of the bronchial tubes, and to the connective tissue of the lung. This tissue intervenes everywhere in small quantity between the in- fundibula (interstitial tissue), and forms a distinct layer, containing much elastic tissue, covering the surface of the lung underneath the THE TRACHEA AND LUNGS 123 Fig. 148. — Section- of tart of cat's lung, stained with nitrate of silver. (Highly magnified.) The small granular and the large Battened cells of the alveoli are shown. In the middle is a i] "i a Lobular bronchial tube, with a patch of the granular pavement-epithelium on one side. Fig. 149. — Section of injected lung, including several contiguous alveoli. I Highly magnified. ) ", n, free edges of alveoli; c, c partitions ; ghbouring alveoli, seen in section; ■' arterial branch giving off capillaries - either side oi el] exhibited. geueous alveolar wall with nuclei of connective-tissue corpuscles, and elastic fibres. 124 THE ESSENTIALS OF HISTOLOGY serous membrane (subserous tissue). In some animals tins subserous layer contains plain muscular tissue, which is especially developed near the lung-apex. The lymphatics of the lung form two sets of vessels, one set accompanying the bronchial tubes, and another set forming a network in the interstitial connective tissue, and in the subserous tissue. Both sets of lymphatics tend towards the hilus and enter lymphatic glands at the root of the lung. Those in the subserous tissue communicate by means of stomata between the epithelial cells of the serous mem- brane with the cavity of the pleura. The pleura, which covers the surface of the lung, has the usual structure of a serous membrane. It is provided with a special network of capillary blood-vessels, which are supplied by branches of the bronchial arteries. 125 LESSON XXVI. STRUCTURE OF THE TEETH, THE TONGUE, AND MUCOUS MEMBRANE OF THE MOUTH. 1. Study first with the low power and afterwards with the high power a longitudinal section of a human tooth which has been prepared by grinding. It is better to purchase this specimen, for the process of preparation is difficult and tedious without the aid of special apparatus. Examine carefully the enamel, the dentine, and the cement. The dark appearance of the dentinal tubules is due to their containing ah* in the dried specimen. Measure the diameter of the enamel prisms and of some of the dentinal tubules. Make sketches from each of the tissues. 2. Mount in Canada balsam a section of a tooth in situ, which has been decalcified in chroinic or picric acid and stained with logwood or borax- carmine. In this section the mode of implantation of a tooth, as well as the structure of the pulp, can be made out. Make a general sketch under a low power, and under a high power draw a srnall piece of the pulp showing the processes of the odontoblasts extending into the dentinal tubules. 3. The development of the teeth and the formation of their tissues are studied in sections made across the snout and lower jaw of foetal animals. The preparation should be stained in bulk with alcoholic magenta, borax- carmine, or hematoxylin, and embedded hi paraffin, and the sections mounted by the shellac-creosote process (see Appendix). 4. Section across the whole tongue of a small mammal ; stahi with log- wood, and mount in Canada balsam. In these sections the arrangement of the muscular fibres and the structure of the papillae of the mucous mem- brane may be studied ; and if the organ have been previously injected, the arrangement of the blood-vessels in the muscular tissue and in the mucous membrane will also be well seen. THE TEETH. A tooth consists of three calcified tissues : the enamel, which is of epithelial origin, the dentine, and the cement, or crusta petrosa. The dentine forms the mam substance of a tooth, the enamel covers the crown, and the cement is a layer of bone which invests the root (fig. 150). The enamel is formed of elongated hexagonal prisms (fig. 151), which are set vertically, or with a slight curvature upon the surface of the dentine. They are marked at tolerably regular intervals with slight transverse shadings producing an indistinct cross-striated ap- pearance. Sometimes coloured lines run through the enamel across the direction of its fibres. 126 THE ESSENTIALS OF HISTOLOGY The dentine is composed of a hard dense substance like bone, but containing no Haversian canals or lacuna?. It is pierced everywhere, however, by fine canaliculi {dentinal tubules, figs. 152, 153), which radiate outwards from a central cavity which, during life, contains the pulp. The tubules branch at acute angles as they pass outwards I their branches become gradually finer towards the periphery of the Fig. 150. — Vertical section* of a tooth in situ. (15 diame- ters. ) c, is placed in the pulp- cavity, opposite the cervix or neck of the tooth ; the part above is the crown, that below is the root (fang). 1, enamel with radial and concentric markings ; 2, dentine with tubules and incremental lines ; 3, cement or crusta pe- trosa,with bone corpus- cles ; 4, dental perios- teum ; 5, boue of lower jaw. dentine. The tubules have a proper wall of their own, which can be isolated by steeping a section of tooth in strong hydrochloric acid. In the living tooth they are occupied by protoplasmic fibres, which are pro- longed from the superficial cells of the pulp. The intertubular substance is for the most part homogeneous, but here and there indications can be seen of its deposition in the form of globules. This is especially the case near the surface of the dentine, STRUCTURE OF THE TEETH A 127 Fig. 151. — Enamel prisms. ^350 diameters.) A, fragments and single fibres of the enamel, isolated by the action of hydrochloric acid B, surface of a small fragment of enamel, showing the hexagonal ends of the fibres. Fig. 152. — Section of fang, pa- rallel To THE DENTINAL TU- BULE-. ( Magnified 300 diameters.) 1, cement, with large bone-lacuna- and indications ; 2, granular layer ot Purkinje ( interglobular spaces); 3, dentinal tubules. Fig. 153. — Si < rioxs or DENTINAL TUBULES. a, cut across : b. cut obliquely. (About 300 diameters.) where the globular deposit and the interglobular spaces may produce a granular appearance [granular layer, fig. l'rl, 2), and also in the 128 THE ESSENTIALS OF HISTOLOGY course of certain lines or clefts which are seen traversing die dentine across the direction of the tubules [incremental lines, fig. 150, shown magnified in fig. 154). Fig. 154. — A small portion ok the dentine with interglobular spaces. (350 diameters.) c, portion of incremental line formed by the interglobular spaces, which are here filled up by a transparent material. The pulp consists of a soft, somewhat jelly-like, connective tissue, containing many branched cells, a network of blood-vessels, and some nerve fibres which pass into the pulp-cavity along with the blood- vessels by a minute canal at the apex of the fang. The superficial cells of the pulp form an almost continuous layer, like an epithelium. They are known as odontoblasts, from having been concerned in the formation of the dentine. The crusta petrosa (fig. 152, l) is a layer of lamellated bone in- cluding lacunae and canaliculi, but without Haversian canals, at least normally in the human teeth. It is covered with periosteum (dental 'periosteum), which also lines the socket, and serves to fix the tooth securely. Formation of the teeth. — The teeth are developed in the same manner as the hairs. A thickening of the epithelium occurs along the line of the gums, and grows into the corium of the mucous membrane (common enamel-germ, fig. 155, A). At regular intervals there is yet a further thickening and growth from the common enamel-germ into the tissue of the mucous membrane, each of these special rudiments swelling out below into a flask-shaped mass of cells, the special enamel-germ, fig. 155, B). A vascular papilla grows up from the corium into the bottom of the special enamel-germ (fig. 155, C, D) ; this papilla has the shape of the crown of the future tooth. Each special enamel- germ, with its included papilla, presently becomes cut off from the epithelium of the mouth, and surrounded by a vascular membrane — the dental sac. The papilla becomes transformed into the dentine of the future tooth, and the enamel is deposited upon its surface by the epithelial cells of the enamel-germ. The root of the tooth, with its covering of cement, is formed at a later period, when the tooth is DEVELOPMENT OF THE TEETH 129 r—~ l. r S^^v^Xg^ Wm Fig. 155. A. Section across the uppj i: jaw of a FCETAL sheep. (3 centimeters long.) 1, common enamel-germ dipping down into the mucous membrane where it is half surrounded bj ;> semilunar-shaped more dense-looking tissue, the germ of the dentine and dental sac ; ■2, palatine process of the maxilla. B. Section similar ro that shown- in the previous figure, but passing THROUGH ONE OF Till: SPE( IAL ENAMEL-GERMS HERE BECOMING FLASK-SHAPED. c, c', epithelium of mouth ; /, neck ; f, body of special enamel-germ. C ami D. Sections at later stages than A and B, the papilla having be- COME FORMED AND INDENTED 1 lit ENAMEL-GERM, WHICH HAS AT THE SAME TIME GROWN PARI I.Y ROl NI> IT. c. epithelium of gum, sketched in outline : /', neck of enamel-germ; f, enamel-organ ; e, its ctions into the corium : ;•. papilla; I, dental 5ac funning. In D, the enamel-germ {Jp ) of the corresponding permanent tooth has become formed. 130 THE ESSENTIALS OF HISTOLOGY beginning to grow np through the gum, by a gradual elongation of the base of the papilla. Previously to the deposition of the enamel, the enamel-germ under- goes a peculiar transformation of its previously rounded epithelium - Fig. 156. — A section through the EN AM EL-ORGAN AND DENTAL SAC FROM THE TOOTH OF A CHILD AT BIRTH. (250 diameters.) a, outer dense layer of the dental sac ; b, inner looser texture of the same with capillary blood- vessels and a somewhat denser layer towards the enamel organ : c, spongy substance ; rf, inner cells ; aud e, outer cellular layer of the euauiel- organ. Fig. 157. — Part of section of develop- ing TOOTH OF YOUNG RAT, SHOWING THE MODE OF DEPOSITION OF THE DEN- TINE. (Highly magnified.) a, outer layer of fully calcified dentine ; 6, un- calcified matrix, with a few nodules of calca- reous matter ; c, odontoblasts with processes extending into trie dentine; d, pulp. The sec- tion is stained with carmine, which colours the uncalcified matrix, but not the calcified part. cells into three layers of modified cells. One of these is a layer of columnar cells (fig. 156, d), which immediately covers the surface of the dentine. These columnar cells form the enamel-prisms either by a deposition of calcareous salts external to them, or by a direct calcification of their protoplasm. The cells next to the dental sac form a single layer of cubical epithelium (e), all the other cells of the THE TONGUE 131 enamel-germ become transformed into branching corpuscles {Cj com- municating by their processes, and thus forming a continuous net- work. The enamel-germ, after it is thus modified, is known as the enamel-organ. The dentine of the tooth is formed by calcification of the surface of the papilla. At this surface there is a well-marked layer of odonto- blasts (fig. 157), and these produce a layer of dentinal matrix which forms a sort of cap to the papilla, and which soon becomes calcified by the deposition of globules of calcareous matter. Processes of the odontoblasts remain in the dentine as it is forming, and thus the dentinal tubules are produced. Subsequently other layers of dentine are formed within the first by a repetition of the same process, and in this way the papilla gradually becomes calcified. A part, however, remains unaltered in the centre of the tooth, and with its covering of odontoblasts forms the pulp. The ten milk-teeth are formed in each jaw in this manner. These, however, become lost within a few years after birth, and are replaced by permanent teeth in much the same way that a new succes- sion of hairs occurs. A small outgrowth takes place at an early period from the enamel-germ of each of the milk-teeth (fig. 155, T),fp), and this eventually becomes the germ of the corresponding permanent tooth. It gradually enlarges, acquires a papilla, forms an enamel- organ, in short, passes through the same phases of development as its parent germ, and when the milk-tooth drops out of the jaw in conse- quence of the absorption of its roots (by osteoclasts) the permanent tooth grows up into its place. But there are six permanent teeth in each jaw which do not suc- ceed milk-teeth ; these are the permanent molars. They are developed from an extension backwards of the original epithelial thickening (common enamel-germ) and the downgrowth from this into the corium of three successive special enamel -germs at comparatively long intervals of time. Within these the tissues of the permanent molars become formed in a manner exactly similar to that in which the milk-teeth are developed. THE TONGUE. The tongue is mainly composed of striated muscular fibres, running, some longitudinally, and others transversely. It is coveted by a mucous membrane, the epithelium of which, like that of the rest of the mouth, is thick and stratified, and conceals microscopic papillae (fig. 158) like those of the skin. Besides these, the upper surface of the organ is covered with larger papilla', which give it a rough appearance. These, which ore termed the Ungual papilla, are of three kinds: (1) About twelve or thirteen comparatively large circular projections, each of which is surrounded by a narrow groove (fossa), external to which the mucous k2 132 THE ESSENTIALS OF HISTOLOGY Fig. 158. — Section op mucous membrane of mouth. showing three microscopic PAl'ILL.E AND STRA- TIFIED EPITHE- LIUM. The blood- vessels HAVE BEEN INJECTED. (Toldt.) Fig. 159.— Section of circumvallate papilla, ii (man. The figure includes one side of the papilla and the adjoining part of the vallum. (Magnified 150 diameters.) (Heitzmann.) E, epithelium ; G, taste-bud ; C, eoriura with injected blood- vessels ; M, gland with duct. Fig. 1G0. — Section of fungiform papilla, HUMAN, (Heitzmann.) E, epithelium ; Gcorium; L, lymphoid tissue ; M, muscular fibres of tongue. Fig. 161. — Section <>f two filiform papillae, human. (Heitzmann.) (Letters as in previous figure.) THE GUSTATORY ORGANS 133 membrane is raised above the general level (vallum) (fig. 159 1. These papilla form a V-shaped line towards the back of the tongue ; they receive filaments of the glosso-pharyngeal nerve, and have taste-buds in the epithelium which covers their sides, and in that of the side of the vallum. They are known as the circumvallate papilla. (2) All the rest of the papillary surface of the tongue is covered by conical papilla, so named from the conical pointed cap of epithelium which is borne by each ; sometimes this cap is fringed with fine epithelial filaments, when they are termed filiform (fig. 161). (3) Scattered here and there amongst the conical papilla? are other larger papilhe, the fungiform (fig. 160). These are very vascular, and lie partly embedded in little depressions of the mucous membrane. Small tubular glands may be seen between the superficial muscular fibres sending their ducts to the surface. Most of them secrete mucus, but those which open into the trenches of the circumvallate papillae, and a few others elsewhere, yield a serous secretion. The mucous membrane at the back of the tongue contains a large amount of lymphoid tissue. The taste-buds. — The minute gustatory organs which are known as taste-buds may be seen in sections which pass through the papilla? vallatae or the papillae fungiformes ; they are also present here and there in the epithelium of the general mucous membrane of the tongue, especially at the back and sides, and occur also upon the under surface of the soft palate, and on the epiglottis. But they are most easily studied in the papilla? foliatas of the rabbit, two small oval areas lying Fig. 162. — Tongue of rabbit, showing the situation of the l'AI'II.L.E I-uLlAl.E. /;. on cither side of the back of the tongue and marked transversely with a number of small ridges or laminae with intervening furrows (see figs. 162 and 168J. Sections across the ridges show numerous taste-buds embedded in the thick epithelium which clothes their sides. The taste-buds are ovoid clusters of epithelium-cells which lie in cavities in the stratified epithelium (fig. 164). The base of the taste- bud rests upon the corium of the mucous membrane, and receives a branch of the glosso-pharyngeal nerve ; the apex is narrow and com- 104 THE ESSENTIALS OF HISTOLOGY municates with the cavity of the mouth by a small pore in the super- ficial epithelium (gustatory pore, fig. 104, p). i! i ... n ! S-f^: m Fig. 163. — Vertical section of papilla foliata of the rabbit, passing across the folle. (Ranvier.) p, central lamina of the corium ; v, section across a vein, which traverses the whole length of the folia ; p', lateral lamina in which the nerve-fibres run ; g, taste-bud ; n, sections of nerve-bundles ; a, serous gland. Fig. 164. — Section through the middle of a taste-bud. (Ranvier.) p, gustatory pore ; s, gustatory cell ; r, sustentacular cell : nt, lymph-cell, containing fatty granules ; e, superficial cells of the stratified epithelium ; n, nerve-fibres. The cells which compose the taste-bud are of two kinds, viz. : 1. The gustatory cells (fig. 165, a), which are delicate fusiform or THE GUSTATORY ORGANS 135 bipolar cells composed of the cell-body or nucleated enlargement, and of two processes, one distal, the other proximal. The distal process is nearly straight, and passes towards the apex of the taste-bud, where it terminates in a small, highly refracting cilium-like appendage, which projects into the pore above mentioned. The proximal process is more delicate than the other, and is often branched and varicose ; it is Fig. 165 — Various cells from taste-bud of rabbit. (600 diameters.) g. showing the commencement in a DUCT in the alveoli. (Magnified 4-JJ diameters.) «, one of the alveoli, several <>f which are in the section shown grouped around the commencement oi the duct. ■/': »'. an alveolus, not opened bj the section membrane in section ; e, interstitial connective tissue oi the gland : d, section of a duct which has passed away from the alveoli, and is now lined with characteristically striated columnar cells ; I, semilunar group of darkly stained cells at the periphery of an alveolus. 138 THE ESSENTIALS OF HISTOLOGY Fig. 1G9. — Section of dog's submaxillary, stained. a, duct ; b, alveolus ; c, cresoeut. Fig. 170. — Section of part of the human submaxillary gland. To the right of the figure is a group of mucous alveoli, to the left a group of serous alveoli. Fig. 171. — Alveoli of a serous gland. A, at rest. B, after a short period of activity. C, after a prolonged period of activity. In A and B the nuclei are obscured by the granules of zymogen. THE SALIVARY GLANDS 139 alveoli ; in this it is flattened (cV). The columnar epithelium of the ducts is peculiar, in that the cells show a distinction into two unequal zones, an outer, larger, striated zone, and an inner, smaller, granular one (fig. 168, d). The cells of the alveoli differ according to the substance they secrete. In alveoli which secrete mucus, such as all the alveoli of the dog's submaxillary, and some of the alveoli of the same gland in man (fig. 170), the cells are clear and swollen out with mucigen, which is discharged into the ducts when the gland is stimulated to activity. But in each alveolus there are some smaller cells which do not contain mucigen, and these generally form crescentic groups which lie next to the basement-membrane (fig. 169, c). These are the so-called crescents Of Gianuzzi ; their constituent cells are also known as marginal cells. In alveoli, on the other hand, which do not secrete mucus, but watery or serous saliva, such as the parotid in all animals, and some of the alveoli of the human submaxillary, the cells are filled with granules when the gland is at rest, although the outer part of each cell may become clear after a long period of secretion (fig. 171). The largest ducts have a wall of connective tissue outside the base- ment-membrane, and also a few plain muscular cells. The blood-vessels of the salivary gland form a capillary network around each alveolus. The lymphatics commence in the form of lacunar vessels encircling the alveoli. The nerve-fibres, which are derived both from the cerebro- spinal nerves and from the sympathetic, have not been satisfactorily traced to their termination, but they probably become connected with the alveolar cells. THE PHARYNX AND (ESOPHAGUS. The pharynx is composed of a fibrous membrane, which is encircled by striated muscles, the constrictors, and lined by mucous membrane. The mucous membrane is lined in the upper part of the pharynx and on the upper surface of the soft palate with ciliated epithelium, which is continuous with that of the nostrils, and through the Eustachian tube with that of the tympanum. Below the level of the soft palate the epithelium is stratified like that of the mouth and gullet, into which it passes. In certain parts the mucous membrane contains a large amount of lymphoid tissue, especially at the back, where it forms a projection which is sometimes termed the pharyngeal tonsil, and there are numerous mucous glands opening on its surface. The oesophagus or gullet, which passes from the pharynx to the stomach, consists, like the pharynx, of a fibrous covering, a muscular coat, a lining mucous membrane, and intervening connective tissue (areolar coat) (fig. 172). The muscular coat is much more regularly arranged than that of the pharynx, and is composed of striated muscle in about its upper third only, the rest being of the plain variety. There 140 THE ESSENTIALS OF HISTOLOGY are two layers of the muscular coat, an outer layer, in which the fibres run longitudinally, and an inner, in which they course circularly. The mucous membrane is lined by a stratified epithelium, into which micro- scopic papilla? from the corium project. The corium is formed of areolar tissue, and its limits are marked externally by a narrow layer of longi- £^ mm Fig. 172. — Section of the human (esophagus. The section is transverse, and from near the middle of the gullet, a, fibrous covering ; b, divided fibres of the longitudinal muscular coat ; c, transverse muscular fibres ; . i \ i > j ■ ■ Fig. 181. — Section of the ileum through a lymphoid nodule. (Cadiat.) a. middle of the nodule with the lymphoid tissue partly fallen away from the - b, epithelium of the intestine ; c, villi : their epithelium is partly broken away ; d, crypts of Lieberktthn. together form the agminated glands or patches of Peycr. The latter occur chiefly in the ileum. The villi with which the whole of the inner surface of the small 150 THE ESSENTIALS OF HISTOLOGY intestine is closely beset are clavate or finger-shaped projections of the mucous membrane, and are composed, like that, of lymphoid tissue and covered with columnar epithelium (fig. 182). The characters of this have been already described (Lesson VII.). Between and at the base of the epithelium-cells many lymph-corpuscles occur. The epithelium rests upon a basement-membrane formed of flattened cells. In the middle of the villus is a lacteal vessel (c. I) which is somewhat enlarged near its commencement. Surrounding this vessel are small Fig. 182. — Cross-sectiox of a villus of the cat's ixtesttxe. columnar epithelium : g. goblet cell, its mucus is seen partly exuded: 7. lymph-corpuscles between the epitheiium-cells ; 6, basement-membrane ; c, blood-capillaries ; m, section of plain muscular fibres ; c. I, central lacteal. Fig. 183. — Magnified view of the blood-vessels of the intestinal villi. The drawing was taken from a preparation injected by Lieberkuhn, and shows, belonging to each villus, a small artery and vein with the intermediate capillary network. bundles of plain muscular tissue prolonged from the muscularis mucosa?. The network of blood -capillaries (fig. 183) lies for the most part near the surface within the basement -membrane ; it is supplied with blood by a small artery which joins the capillary network at the base of the villus ; the corresponding vein generally arises nearer the extremity. The lymphatics (lacteals) of the mucous membrane (fig. 184 1, after STRUCTURE OF THE INTESTINE 151 receiving the central lacteals of the villi, pour their contents into a plexus of large valved lymphatics which lie in the submucous tissue and form sinuses around the bases of the lymphoid nodules. From the submucous tissue efferent vessels pass through the muscular coat, receiving the lymph from an intramuscular plexus of lymphatics, and are conveyed away between the layers of the mesentery. y f Fig. 184. — Vertical section of a portion of a pah h of Peter's glands, with the lacteal VESSELS injected. (32 diameters.) (Frev.) The specimen is from the lower part of the ileum : a, villi, with their lacteals left white ; 6, some of the tubular glands ; c the muscular layer of the mucous membrane ; d, cupola or projecting part of the nodule; e, central part;/, the reticulated lacteal vessels occu- pying the lymphoid tissue between the nodules, joined above by the lacteals from the villi and mucous surface, and passing below into g, the sinus-like lacteals under the nodules, which again pass into the large efferent lacteals, g' ; i, part of the muscular coat. Absorption of fat. — The lymph-corpuscles of the villi are the chief agents hi effecting the passage of fat-particles into the lacteals. In order to study this process of transference, it is convenient to stain*" the fat-particles with osmic acid, which colours them black. It can then be observed that in animals which have been fed with fat these particles are present (1) in the columnar epithelium-cells; (2) in the lymph-cells ; and (3) in the central lacteal of the villus. The lymph- cells are present not only in the reticular tissue of the villus, but also in considerable number between the epithelium-cells ; and they can also be seen in thin sections from osmic preparations within the com- mencing lacteal ; but in the last situation they are hi every stage of disintegration. Since the lymph-cells are amoeboid, it is probable from these facts that the mechanism of fat-absorption consists of the following pro- cesses — viz. il) absorption of fat into the columnar epithelium-cells of the surface; (2) inception of fat by the lymph-corpuscles in the epi- thelium, partly from the epithelium-cells, and partly, perhaps, directly 152 THE ESSENTIALS OF HISTOLOGY from the intestinal contents; (3) migration of the lymph-corpuscles carrying the incepted fat-particles by their amoeboid movements through the tissue of the villus and into the central lacteal; (4) disintegration and solution of the immigrated lymph-corpuscles, and setting free both of their fatty contents and also of the proteid matters of which they are themselves composed. Fig. 185, A. — Section of the villus of a rat killed during fat-absorption. ep, epithelium : sir, striated border : c, lymph-cells : c', lymph-cells in the epithelium ; I, central lacteal containing disintegrating lymph-corpuscles. Fig. 185, B. — Mucous membrane of frog's intestine during fat-absorption. ep, epithelium ; str, striated border ; c, lymph-corpuscles ; I. lacteal. This migration of the lymph-corpuscles into the lacteals of the villi is not a special feature of fat-absorption alone, but occurs even when absorption of other matters is proceeding ; so that the transfer- ence of fat -particles is merely a part of a more general phenomenon accompanying absorption. THE LARGE INTESTINE. The large intestine has the usual four coats, except near its ter- mination, where the serous coat is absent. The muscular coat is pecu- liar in the fact that along the caecum and colon the longitudinal muscular fibres are gathered up into three thickened bands which pro- duce puckerings in the wall of the gut. STRUCTURE OF THE INTESTINE 153 The mucous membrane of the large intestine is beset with simple tubular glands somewhat resembling the crypts of Lieberkiihn of the small intestine, and lined by columnar epithelium similar to that of the inner surface of the gut, but containing many more mucus- secreting or goblet cells (fig. 186). The extremity of each gland is usually slightly dilated. The interglandular tissue is like that of the Fig. 186. — A gland of the LARGE INTESTINE OF THE DOG. (From Heidenhain and Klose.) 6, In longitudinal, c, in transverse section. stomach, as is also the arrangement of the blood-vessels and lymphatics in it. The nerves of the large intestine also resemble those of the small intestine and stomach in their arrangement. At the lower end of the rectum the circular muscular fibres of the gut become thickened a little above the anus so as to form the internal sphincter muscle. In this region also there are a number of compound racemose mucous glands opening on to the surface of the mucous membrane. 154 THE ESSENTIALS OF HISTOLOGY LESSON XXXI. STRUCTURE OF THE LIVER AND PANCREAS. 1. Make sections of liver and study them carefully with a low and high power. Sketch the general arrangement of the cells in a lobule under the low power and under the high power. Make very careful drawings of some of the hepatic cells and also of a portal canal. 2. Study, first of all with the low and afterwards with a high power, a section of the liver in which both the bli »< id-vessels and the bile-ducts have been injected. Make a general sketch of a lobule under the low power and draw a small part of the network of bile-canaliculi under the high power. 3. Tease a piece of fresh liver in salt solution for the study of the appear- ance of the hepatic cells in the recent living condition. 4. Prepare sections of the pancreas from a gland which has been hardened in alcohol. The sections are stamed with borax-carmine and mounted in the usual way in Canada balsam. Make a sketch under the low power. 5. Tease a small piece of fresh pancreas in salt solution. Notice the granules in the alveolar cells, chiefly accumulated in the half of the ceU which is nearest the hunen of the alveolus, leaving the outer zone of the cell clear. Sketch a small portion of an alveolus under a high power. THE LIVER. The liver is a solid glandular mass, made up of the hepatic lobules. These are polyhedral masses (about 1 mm. in diameter i of cells, separated from one another by connective tissue. In some animals, as in the pig, this separation is complete, and each lobule is isolated, but in man it is incomplete. There is also a layer of con- nective tissue underneath the serous covering of the liver, and forming the so-called capsule of the organ. The blood-vessels of the liver (portal vein and hepatic artery) enter it on its under surface, where also the bile-duct passes away from the gland. The branches of these three vessels accompany one another in their course through the organ, and are enclosed by loose connec- tive tissue (capsule of Grlisson), in which are lymphatic vessels, the whole being termed a portal canal (fig. 187). The smallest branches of the vessels penetrate to the intervals between the hepatic lobules, and are known as the interlobular branches. The blood leaves the liver at the back of the organ by the hepatic veins : the branches of these run through the gland unaccompanied by other vessels (except STRUCTURE OF THE LIVER 156 lymphatics) and can also be traced to the lobules, from each of which they receive a minute branch I intralobular vein) which passes from the centre of the lobule, and opens directly into the (sublobular) branch of the hepatic vein. Fig. 187. — Section of a portal canal. a, branch of hepatic artery : v, branch of portal vein : d, bile-duct : /./, lymphatics in the areolar tissue of Glisson's capsule which encloses the vessels. Fig. 188. — Diagrammatic representation of two hepatic lobules. The left-hand lobule is represented with the intralobular vein out across ; in the risht-hand one the section takes the '-cur-.- of the intralobular vein, p, interlobular branches of the portal vein; h Intralobular branches of the hepatic reins; s, sublobular vein ; c, capil- laries of the lobules. The arrows indicate the direction of the course of the blood. The liver-cells are onlj represented in one part oi each Lobule. Each lobule is a mass of hepatic cells pierced everywhere with a network of blood-capillaries ifi,^ r . 188), which arise at the periphery of the lobule, there receiving blood from the interlobular branches of the portal vein (p), and converge to the centre of the lobule, where they unite to form the intralobular branch of the hepatic vein. The inter- 156 THE ESSENTIALS OF HISTOLOGY lobular branches of the hepatic arteries join this capillary network a short distance from the periphery of the lobule. The hepatic cells (fig. 189 1, which everywhere lie between and sur- round the capillaries, are polyhedral, somewhat granular -looking cells, Fig. 189. — Section of rabbit's liver with the intercellular network of bile-canaliculi injected. (Highly magnified.) (Hering.) Two or tliree layers of cells are represented ; 6, b. blood-capillaries. each containing a spherical nucleus. After a meal, the cells in the outer part of the lobule may become filled with fat, and masses of glycogen can also frequently be seen within the cells. The bile-ducts commence between the hepatic cells in the form of fine canaliculi, which lie between the adjacent sides of two cells, and form a close network, the meshes of which correspond in size to the cells (fig. 189). At the periphery of the lobule these fine canaliculi pass into the interlobular bile-ducts (fig. 190), the columnar epithe- lium-cells of which become, by a gradual transition, changed into cubical and polyhedral cells, which join those of the hepatic lobules. The bile-ducts are lined by clear columnar epithelium (fig. 187, d). Outside this is a basement-membrane, and in the larger ducts some fibrous and plain muscular tissue. Many of the larger ducts are beset with small cascal diverticula. The gall-bladder is in its general structure similar to the larger bile- ducts. It is lined by columnar epithelium, and its wall is formed of fibrous and muscular tissue. The lymphatics of the liver are said to commence as perivascular lymphatic spaces enclosing the capillaries of the lobules. Efferent lymphatics pass away from the organ in the connective tissue which invests the portal and hepatic veins. STRUCTURE OF THE PANCREAS 157 Fig. 190. — Lobule of rabbit's liver, vessels and bile-ducts injected. (Cadiat.) a, central vein ; 6, b, peripheral or interlobular veins ; c, interlobular bile-duct. THE PANCREAS. The pancreas is a tubulo-racemose gland, resembling the salivary glands, so far as its general structure is concerned, but differing from them in the fact that the alveoli, in place of being saccular, are longer and more tubular in character (fig. 191 ). Moreover, the connective tissue of the gland is somewhat looser, and there occur in it at intervals small groups of epithelium-like cells, which are supplied with a close network of convoluted capillary vessels ; their function is unknown, but their presence is very characteristic of the pancreas. The cells which line the alveoli are columnar or polyhedral in shape. When examined in the fresh condition, or in osmic prepara- 158 THE ESSENTIALS OF HISTOLOGY tions, their protoplasm is filled in the inner two-thirds with small granules, but the outer third is left clear (fig. 192, A). After a period of im®0$Sk* Fig. 191. — Section of the pancreas of the dog. d, termination of a duct in the tubular alveoli, ah: B. Fig. 192. — Part of ax alveolus of the rabbit's pancreas, A, at rest; B, after active secretion. (Foster, after Kiihne and Lea.) a, the inner granular zone, which in A is larger and more closely studded with fine granules than in B, in which the granules are fewer and coarser : b, the outer transparent zone, small in A, larger in B, and in the latter marked with faint striae; c. the lumen, very obvious in B, but indistinct in A ; d, an indentation at the junction of two cells, only seen in B. activity the clear part of the cell becomes larger, and the granular part smaller (B). In stained sections the outer part is coloured more deeply than the inner. In the centre of each acinus there may generally be seen some spindle-shaped cells, the nature of which (whether epithelial or con- nective tissue) has not been determined (centro- acinar cells of Lan- gerhans). 159 LESSON XXXII. STRUCTURE OF THE SPLEEN, SUPRARENAL CAPSULE, AND THYROID BODY. 1. Sections of the spleen stained with logwood. Notice the trabecular extend- ing into the substance of the organ from the capsule. Notice also that the glandular substance is of two kinds, (1) lymphoid tissue accumulated round the smaU arteries and here and there massed to form lymphoid nodules — the Malpighian corpuscles of the spleen — and, (2) a tissue consisting of a reticulum of branched and flattened cells containing blood in its interstices and pervaded by capillaries and venous radicles. Sketch part of a section under a low power and a small portion of the reticulum under a high power. 2. Sections across a suprarenal capsule. Examine first with a low power, noticing the general arrangement and extent of the cortical and medullary parts of the organ, making a general sketch which shall include both. Afterwards sketch carefully under the high power a group of cells from each part of the organ. 3. Sections of the thyroid body stained with logwood. Notice the vesicles lined with cubical epithelium and filled with a ' colloid ' substance which be- comes stained by the logwood. Notice also in some parts of the sections a peculiar highly vascular retiform tissue. Sketch a part of this tissue and also one or two vesicles. Measure several vesicles. THE SPLEEN. The spleen is the largest of the so-called ductless glands. It appears to be connected in some way with the elaboration of the blood, white blood-corpuscles being certainly formed and the coloured blood- corpuscles being probably submitted to destruction within it. Like the lymphatic glands, the spleen is invested with a fibrous and muscular capsule (fig. 193, A), and this again has a covering derived from the serous membrane. The capsule sends fibrous bands or tra- becules (b) into the organ, and these join with a network of similar trabecular which pass into the gland at the hilus along with the blood- vessels. In the interstices of the fibrous framework thus constituted lies a soft pulpy substance containing a large amount of blood, and therefore of a deep red colour, dotted within which are here and there to be seen small whitish specks, the Malpighian corpuscles of the spleen (c, c). These are composed of lymphoid tissue which is gathered up into masses which surround the smaller arteries, whilst the red pulp which everywhere surrounds them and which forms the bulk of the 160 THE ESSENTIALS OF HISTOLOGY organ is composed of a close network or sponge work of flattened and branched cells like connective-tissue corpuscles. Coursing through the pulp and communicating with its interstices are capillary blood-vessels Fig. 193. — Vertical section of a small superficial portion of the human SPLEEN, AS SEEN WITH A Low POWER. A, peritoneal and fibrous covering ; 6, trabecular ; c. c, Malpighian corpuscle?, in one of which an artery is>een cut transversely, in the other longitudinally ; d, injected arterial twigs ; «, spleen-pulp. Fig. 194. — Thin section of spleen-pulp, highly magnified, showing the mode of origin of a small vein in the interstices of the pulp. r, the vein, filled with blood-corpuscles, which are in continuity with others, W, filling up the interstices of the retiform tissue of the pulp ; w, wall of the vein. The shaded bodies amongst the red blood-corpuscles are pale corpuscles. which are connected with the terminations of the arteries ; whilst in other parts venous channels arise from the pulp, and bring the blood which has passed into its interstices from the arterial capillaries STRUCTURE OF THE SUPRARENAL CAPSULES 161 towards the larger veins of the organ, which run in the trabecular, and are by them conducted to the hilus. The arteries, which are also at first conducted from the hilus along the trabecule into the interior of the organ, presently leave the trabecular, and their external coat becomes converted into a thick sheath of lymphoid tissue which invests them in the remainder of their course, and in places becomes swollen into the Malpighian corpuscles already mentioned. These small arteries distribute a few capillaries to the Malpighian corpuscles, and then break up into pencils of small vessels which open into the pulp in the manner already mentioned. The cellular elements of the spleen-pulp are of three kinds, viz. large, amoeboid, connective-tissue cells, also called splenic cells, lymph- corpuscles, and the branched, flattened cells which form the sponge- work. The first-named are frequently found to contain coloured blood-corpuscles in their interior in various stages of transformation into pigment. The lymphatics of the spleen run partly in the trabecular and cap- sule, and partly in the lymphoid tissue ensheathing the arteries. They join to form larger vessels which emerge together at the hilus. TEE SUPRARENAL CAPSULES. The suprarenal capsules belong to the class of bodies known as duct- less glands, but they are entirely different in structure from the spleen and lymphatic glands. A section through the fresh organ (fig. 195; Fig. 195. — A vertical section of the suprarenal body of a fcetus, twice THE NATURAL SIZE, SHOWING mi: DISTINCTION BETWEEN THE MEDULLARY AND Col: IK AL SUBSTANI E. r, issuing vein ; r, summit of kidney. shows a cortical zone which is striated vertically to the surface, and of a yellowish colour, and a medulla which is soft and highly vascular, and of a brownish-red colour. The whole organ is invested by a iibrous capsule which sends iibrous septa inwards to the cortical substance I fig. 19G), subdividing this for the most part into columnar groups of cells (zona fasciculata, c). Immediately underneath the capsule, however, M 162 THE ESSENTIALS OF HISTOLOGY the groups are more rounded (zona glomerulosa, b), whilst next to the medulla they have a closely reticular arrangement (zona reticularis, d), and a similar disposition both of the cells and the connective tissue is noticeable throughout the medulla. The cells which form the rounded groups and columns of the cortical substance are polyhedral in form (fig. 197) ; each contains a clear round nucleus, and there are often yellowish oil-globules in their protoplasm. Fig. 196. — Vertical section of supra renal body. (Magnified.) 1, cortical substance ; 2, medullary substance ; a, capsule ; 6, zona glomerulosa ; c. zona fascieulata ; d, zona reticularis ; e, groups of medullary cells ;/, section of a large vein. Fig. 197. — Cells and cell-groups from the outermost layer of the cortical substance of the suprarenal body. Fig. 198. — A small portion of the MEDULLARY PART OF THE SUPRA- RENAL CAPSULE OF THE OX. No blood-vessels penetrate between these cells, both the blood-vessels and lymphatics of the cortex running in the fibrous septa between the columns ; the lymphatics have been stated to communicate with fine spaces which run between the cells of the columns. The cells of the medulla (fig. 198) are more irregular in shape, and are often branched. Their protoplasm is either clear, or it may in some animals contain a brownish pigment, but in man the dark red colour of STRUCTURE OF THE THYROID BODY 163 the medulla is largely due to the blood contained in the large venous spaces by which it is pervaded, and which receive the blood after it has traversed the capillaries of the cortex. Investing the larger veins are bundles of plain muscular fibres ; and numerous nerves, after traversing the cortical substance, are distributed throughout the medulla, where they form a close plexus provided with ganglion-cells. THE THYROID BODY. The thyroid body consists of a framework of connective tissue en- closing numerous spherical or oval vesicles (fig. 199) which are lined with cubical epithelium. The cavities of the vesicles are filled with a peculiar viscid liquid which is coagulated by alcohol and which then becomes stained by hematoxylin. A similar material has been found Fig. 199. — Section of the thyroid gland of a child. Two complete vesicles and portions of others are represented. The vesicles are filled with colloid, which also occupies the interstitial spaces. In the middle of one of the spaces a blood-vessel is seen cut obliquely, and close to it is a plasma-cell. Between the cubical epithelium-cells, smaller cells like lymph-corpuscles are here and there seen. in the lymphatics of the gland, and may sometimes be detected also hi the interstices of the connective tissue. The blood-vessels of the thyroid are exceedingly numerous, and the capillaries form close plexuses round the vesicles. Some of the blood- vessels are distributed to a peculiar highly vascular retiform tissue which occurs in patches here and there in the organ. Disease of the thyroid or its extirpation is accompanied by remark- able changes in the chemical composition of the blood and many of the tissues, resulting chiefly in the accumulation within them of a large amount of ))tit<-iii ; a condition of general myxedema, and eventually of cretinism, being produced. m2 104 THE ESSENTIALS OF HISTOLOGY LESSON XXXIII. STRUCTURE OF THE KIDNEY. 1. Sections passing through the whole kidney of a small mammal, such as a mouse or rat. These sections will show the general arrangement of the organ and the disposition of the tubules and of the Malpighian corpuscles. A general sketch should be made of one of these sections under a low power. 2. Thin sections of the kidney of a larger mammal, such as the dog, may next be studied. In some the direction of the section should be parallel with the tubules of the medulla, and in others across the direction of those tubules. The characters of the epithelium of the several parts of the uriniferous tubules are to be made out in these sections. 3. Separate portions of the uriniferous tubules may be studied in teased preparations from a kidney which has been subjected to some process which renders it possible to unravel the uriniferous tubules for a certain distance. 1 4. Sections of a kidney in which the blood-vessels have been injected. Examine these with a low power of the microscope. Try and follow the course of the arteries — those to the cortex sending their branches to the glomeruli, those to the medulla rapidly dividing into pencils of fine vessels which run between the straight uriniferous tubules of that part. Notice also the efferent vessels from the glomeruli breaking up into the capillaries which are distributed to the tubules of the cortical substance. Make sketches showing these points. The kidney is a compound tubular gland. To the naked eye it ap- pears formed of two portions — a cortical and a medullary — the latter being subdivided into a number of pyramidal portions ( pyramids of Malpighi), the base of each being surrounded by cortical substance, while the apex projects in the form of a papilla into the dilated commence- ment of the ureter (pelvis of the kidney).* Both cortex and medulla are composed entirely of tubules — the uriniferous tubules — which have a straight direction in the medulla and a contorted arrangement in the cortex ; but groups of straight tubules also pass from the medulla through the thickness of the cortex {medullary rays). The uriniferous tubules begin in the cortical part of the organ in dilatations, each enclosing a tuft or glomerulus of convoluted capillary 1 For a method which may be employed for this purpose, see Course of Prac- tical Histology, p. 209. - In many animals the whole kidney is formed of only a single pyramid, but in man there are about twelve. STKUCTUKE OF THE KIDNEY 167 Fig. 202. — Structure of the epithelium of the convoluted tubules. d, section of a convoluted tubule from the rat, showing the unaltered proto- plasm occupying a circular area around the nucleus of each cell ; a, b, c, isolated oells from the convoluted tubules of the rat ; e, isolated cells from the dog's kidney, viewed from the inner surface, and showing the irregular contour of the protoplasm ; /, isolated cells from the newt, showing the rods and the homogeneous cuticular layer. Fig. 203.— Part of a con- voluted TUBULE FROM THE DOGS KIDNEY. Fig. 204.— Portion- of tubules, ISOLATED. (Cadiat) a, large collecting tubule : b, loop of Henle ; c, descending tubule of Heule. 168 THE ESSENTIALS OF HISTOLOGY convoluted tubules, into which these pass. On the other hand, the junctional tubule has a large lumen and is lined by clear flattened cells, and the collecting tubes have also a very distinct lumen and are lined by a clear cubical or columnar epithelium (figs. 201, d; 204, a). Fig. 205. — Section across a papilla of the kidney. (Cadiat.) a, large collecting tubes (ducts of Bellini) ; b, c, d, tubules of Henle ; e,f, blood-capillaries. The following gives a tabular view of the parts which compose a uriniferous tubule, and the nature of the epithelium in each part : Portion of tubule Nature of epithelium Position of tubule Capsule Flattened, reflected over glomerulus . Labyrinth of cortex First convoluted Cubical, fibrillated, ciliated, the cells Labyrinth of cortex tube interlocking Spiral tube Cubical, fibrillated (like the last) Medullary ray of cor- tex Boundary zone and Small or descend- Clear, flattened cells .... ing tube of partly papillary zone Henle of medulla Loop of Henle . Like the last Papillary zone of medulla Larger or ascend- Cubical, fibrillated, sometimes imbri- Medulla, and medul- ing tube of cated lary ray of cortex Henle Zigzag tube Cells strongly fibrillated ; varying in height ; lumen small Labyrinth of cortex Second convo- Similar to first convoluted tube, but Labyrinth of cortex luted tube cells are longer, with larger nuclei, and they have a more refractive aspect Junctional tube . Clear flattened and cubical cells Labyrinth passing to medullary ray Straight or col- Clear, cubical and columnar cells Medullary ray and lecting tube medulla Duct of Bellini . Clear, columnar cells .... Opens at apex of papilla STRUCTURE OF THE KIDNEY 169 Blood-vessels. — The artery of the kidney divides into branches on entering the organ, and these branches pass towards the cortex, forming incomplete arches between the cortex and the medulla (fig. 206, a). The branches of the renal vein form similar but more com- plete arches (g). From the arterial arches vessels pass through the Fig. 206. — Vascular supply of kiuney. (Cadiat.) a, part of arterial arch ; 6, interlobular artery : c, glomerulus : d, efferent vc>-el pa medulla as false art. rect. ; e, capillaries of cortex ; /", capillaries of medulla ; g, veuous arch ; h, straight veins of medulla ; j, vena stellula ; i, interlobular vein. cortex (interlobular arteries, b), and give off at intervals small arteri- oles (efferent vessels of the glomeruli), each of which enters the dilated commencement of a uriniferous tubule, within which it forms a glomerulus. From the glomerulus a somewhat smaller c/r'crcnt vessel passes out, and this at once again breaks up into capillaries, which 170 THE ESSENTIALS OF HISTOLOGY are distributed amongst the tubules of the cortex (e) ; their blood is collected by veins which accompany the arteries and join the venous arches between the cortex and the medulla, receiving in their course certain other veins which arise by radicles which have a somewhat stellate arrangement near the capsule {vena stellula, j). The medulla derives its blood- supply from special offsets of the arterial arches, which almost immediately break up into pencils of fine straight arterioles running in groups between the straight tubules of the medulla. These arterioles gradually break up into a capillary network with elongated meshes which pervades the medulla (fig. 206,/), and which terminates in a plexus of somewhat larger venous capillaries in the papilla?. From these and from the other capillaries the veins Fig. 207. — Section through part of the dog's kidney. p, papillary, and g, boundary zones of the medulla ; c, cortical layer ; A, bundles of tubules in the boundary layer, separated by spaces, b, containing bunches of vessels (not here represented), and prolonged into the cortex as the medullary rays, 77! ; c, intervals of cortex, composed chiefly of convoluted tubules, with irregular rows of glomeruli, between the medullary rays. collect the blood, and pass, accompanying the straight arterioles, into the venous arches between the cortex and medulla. The groups of small arteries and veins (vasa recta) in the part of the medulla nearest the cortex alternate with groups of the uriniferous tubules, and this arrangement confers a striated aspect upon this portion of the medulla {boundary zone, see fig. 207). The efferent vessels of those glomeruli which are situated nearest to the medulla may also break up into pencils of fine vessels (false arteria recta) and join the capillary network of the medulla (fig. 198, d). Between the uriniferous tubules, and supporting the blood-vessels, is a certain amount of connective tissue (fig. 205), within which are cleft-like spaces from which the lymphatics of the organ originate. 171 LESSON XXXIV. STRUCTURE OF THE URETER, BLADDER, AND MALE GENERATIVE ORGANS. 1. Section across the ureter. 2. Section of the urinary bladder vertical to the surface. In the sections of the ureter and of the urinary bladder, notice the transitional epithelium resting on a mucous membrane, which is composed chiefly of areolar tissue without glands, and the muscular coat outside this. In the ureter there is some fibrous tissue outside the muscidar coat, and at the upper part of the bladder there is a layer of serous membrane covering the muscular tissue. Sketch a section of the ureter under a low power, and the epithelium of the bladder under the high power. 3. Section across the penis. The blood-vessels of the organ should have been injected so as the better to exhibit the arrangement of the venous spaces which constitute the erectile tissue. Notice the large venous sinuses of the corpora cavernosa and the smaller spaces of the corpus spongiosum, in the middle of which is seen the tube, of the uretbra. 4. Section across the testis and epididymis. The sections are best made from a rat's testis which has been hardened in alcohol and pieces of which have been stained in bulk in ddute logwood. In these sections notice the strong capsule surrounding the gland, the substance of which consists of tubules which are variously cut, and the epithelium in which is in different conditions of development in the different tubules. Observe the strands of polyhedral interstitial cells lying in the loose tissue between the tubules and the lymphatic clefts in that tissue. Notice also in sections through the epididymis the ciliated epithelium of that tube. Sketch carefully under a high power the contents of some of the semini- ferous tubules so as to illustrate the mode of formation of the spermatozoa. '). Examination of spermatozoa. The spermatozoa are to be obtained fresh from the testis or seminal vesicles of a recently killed animal and ex- amined in saline solution. Their movements may be studied on the warm stage ; to display their structure a very high power of the microscope is necessary. Measure and sketch three or four spermatozoa. The ureter is a muscular tube lined by mucous membrane. The muscular coat consists of three layers of plain muscular tissue, an outer and inner longitudinal and a middle circular. Outside the mus- cular coat is a layer of fibrous tissue in which the blood-vessels and nerves ramify before entering the muscular layer. The mucous membrane is composed of areolar tissue and is lined by transitional epithelium. 172 THE ESSENTIALS OF HISTOLOGY The urinary bladder has a muscular wall lined by a strong mucous membrane and covered in part by a serous coat. The muscular coat consists of three layers, but the innermost is incomplete. The principal fibres run longitudinally and circularly, and the circular fibres are collected into a layer of some thickness which immediately surrounds the commencement of the urethra, form- ing the sphincter vesica. The mucous membrane is lined by a transi- tional stratified epithelium like that of the ureter. The shape and structure of the cells have already been studied. The penis is mainly composed of cavernous tissue which is collected into two principal tracts — the corpora cavernosa, one on each side, and the corpus spongiosum in the middle line inferiorly. All these are bounded by a strong capsule of fibrous and muscular tissue, containing also many elastic fibres and sending in strong septa or trabecule, Fig. 208. — Section of erectile tissue. (Cadiat.) a, trabecular of connective tissue, with elastic fibres, and bundles of plain muscular tissue (c) ; 6, venous spaces. which form the boundaries of the cavernous spaces of the erectile tissue (fig. 208). The arteries of the tissue run in these trabecule, and their capillaries open into the cavernous spaces. On the other hand, the spaces are connected with efferent veins. The arteries of the cavernous tissue may often in injected specimens be observed to form looped or twisted projections into the cavernous spaces [Jielicine arteries of MUllcr). Urethra. — The cross-section of the urethra appears in the middle of the corpus spongiosum in the form of a transverse slit. It is lined by columnar epithelium, except near its orifice, where the epithelium is stratified. The epithelium rests upon a vascular mucous membrane, MALE GENERATIVE ORGANS 173 and this again is supported by a coating of submucous tissue, con- taining two layers of plain muscular fibres — an inner longitudinal and an outer circular. Outside this again is a close plexus of small veins which are connected with, and may be said to form part of, the coi'pus spongiosum. The mucous membrane of the urethra is beset with small mucous glands, simple and compound (glands of Littrc). There are also a number of oblique recesses termed lacunae. Besides these small glands and glandular recesses, two compound racemose glands open into the bulbous portion of the urethra ( Cowper's glands). Their acini are lined by clear columnar cells which secrete mucus. The prostate, which surrounds the commencement of the urethra, is a muscular and glandular mass, the glands of which are composed of tubular alveoli, lined by columnar epithelium, with smaller cells lying between them and the basement-membrane. Their ducts open upon the floor of the urethra. The integument of the penis contains numerous special nerve end- organs of the nature of end-bulbs, and Pacinian bodies have also been S9. *>+•*. * s Fig. 209. — Transvi rsb sec- tion THROUGH THE RIGHT 1 1 -nn.i: AM' l in. rUNlCA VAGINALIS. a, connective tissue enveloping the parietal layer of the tunica vaginalis; 6, this layer itself; tunica vagi- nalis : e, the tunica alnuginea : /, covering of epi- didymis i g) : /*. mediastinum testis : i. branches of the sper- matic artery : k, spermatic vein ; /. vas deferens : m, small artery of the vas deferens ; n, o, septa or processes from the mediastinum to the ?urface. Fig. 210. — Plan of a ver- tical SECTION OF THE TESTICLE, SHOWING THE ARRANGEMENT OF THE DUCTS. The true length and diameter of the ducts have been disre- garded, a. a, tubuli seminiferi coiled up in the separate lobes ; h, vasa recta : e, rete vascu- ln-uiii : •/. vasa efferentia end- ing in theconi vascnlosi ; J, e, g, Convoluted canal of tl didymis ; h. vas deferens : /, 00 of the back part of the tunica albaginea : i. i. fibrous processe- running between the lobes ; / to *, mediastinum. found upon the nerves. Lymphatic vessels are numerous in the in- tegument of the organ and also in the submucous tissue of the urethra. 174 THE ESSENTIALS OF HISTOLOGY The testicle is enclosed by a strong fibrous capsule, the tunica al- buginea (fig. 209, e). This is covered externally with a layer of serous epithelium reflected from the tunica vaginalis. From its inner surface there proceed fibrous processes or trabecular, which imperfectly sub- divide the organ into lobules, and posteriorly the capsule is prolonged into the interior of the gland in the form of a mass of fibrous tissue, which is known as the mediastinum (fig. 209, h ). Attached to the pos- terior margin of the body of the gland is a mass [epididymis) which when investigated is found to consist of a single convoluted tube, receiv- ilfffi j y->. it Q*^&2$ArXS Fig. 211. — Passage of convoluted seminiferous tibii.es into straight tcbcles and of these into the eete testis. n, seminiferous tubules ; b. fibrous stroma continued from the mediastinum testis ; c, rete testis. ing at its upper end the efferent ducts of the testis and prolonged at its lower end into a thick-walled muscular tube, the vas deferens, which conducts the secretion to the urethra. The glandular substance of the testicle is wholly made up of convo- luted tubules, which when unravelled are of very considerable length. Each commences near the tunica albuginea, and after many windings terminates, usually after joining one or two others, in a straight tubule I fig. 211), which passes into the mediastinum^ and there forms, by STRUCTURE OF THE TESTICLE 175 uniting with the other straight tubules, a network of intercom- municating vessels, which is known as the rete testis. From the rete a certain number of efferent tubules arise, and after a few convolutions pass into the tube of the epididymis. Structure of the tubules. — The seminiferous tubules are formed of a basement-membrane, and contain several layers of epithelium-cells. Of these layers, the one next the basement-membrane is a uniform layer of clear cubical cells (lining epithelium), the nuclei of which, for the most part, exhibit the irregular network which is characteristic of Z> is. / 7 Fig. 212. — Section of parts of three seminiferous tubules of the rat. a, with the spermatozoa least advanced in development ; b, more advanced ; c, containing fully developed spermatozoa. Between the tubules are seen strands of interstitial cells with blood-vessels and lymph-spaces. the resting condition. Here and there these epithehum-cells appear enlarged and to project between the more internal layers. Next to this layer of cubical epithelium there is seen a layer of larger cells \ spermatogenic cells), the nuclei of which have the skein- like aspect which is typical of commencing division ; these cells may be two, three, or more deep I as in the tubule a, fig. 212). Next to them, and most internal, are to be seen in some tubules [b and c) a large number of small protoplasmic corpuscles with simple circular nuclei {spermatoblasts). In other tubules these corpuscles are elongated, and the nucleus is at one end, and in others again these elongated cells are converted into evident spermatozoa, which lie in groups with their heads projecting between the deeper cells and connected with one of the enlarged cells of the lining epithelium, and their tails emerging into the lumen of the tubule (fig. 212, b). As they become matured they gradually pass altogether towards the lumen, where they eventually become free (c). During the time that this crop of spermatozoa has been forming, another set of spermatoblasts has been produced by the 170 THE ESSENTIALS OF HISTOLOGY division of the sperniatogenic cells, and on the discharge of the sperma- tozoa the process is repeated as before. The straight tubules which lead from the convoluted seminiferous tubes into the rete testis (fig. I'll) are lined only by a single layer of clear flattened or cubical epithelium. The tubules of the rete also have a simple epithelial lining, but the basement-membrane is here absent, the epithelium being supported directly by the connective tissue of the mediastinum. The efferent tubules which pass from the rete to the epididymis, and the tube of the epididymis itself, are lined by columnar ciliated epithelium, the cilia being very long ; these tubes have a considerable amount of plain muscular tissue in their wall. Fig. 213. — Section across the commencement of the vas deferens. a, epithelium ; b, mucous membrane ; c, d, e. inner, middle, and outer layers of the muscular coat ; /, bundles of the internal cremaster muscles ; g, section of a blood-vessel. The vas deferens (fig. 213) is a thick tube, the wall of which is formed of an outer thick layer of longitudinal bundles of plain muscular tissue ; within this an equally thick layer of circular bundles of the same tissue, and within this again a thin layer of longitudinal muscle. The tube is lined by a mucous membrane, the inner surface of which is covered by columnar non-ciliated epithelium. The connective tissue between the tubules of the testis is of very STRUCTURE OF THE SPERMATOZOA. ]77 loose texture, and contains numerous lymphatic clefts, which form an intercommunicating system of commencing lymphatic vessels. Lying in this intertubular tissue are strands of polyhedral epithelium-like cells (interstitial cells) of a yellowish colour ; they are much more abundant in some species of animals (cat, boarj than in others. They accompany the blood-vessels before these break up to form the capillary networks which cover the walls of the seminiferous tubules. Fig. 214. — Human spermatozoa. 1, in profile ; 2, viewed on the flat : 6, head ; c, middle-piece ; d, tail ; e, end-piece of the tail. The spermatozoa. — Each spermatozoon consists of three parts, a head, a middle part or body, and a long tapering and vibratile tail. In man (fig. 214) the head is of a flattened oval shape, somewhat more flattened and pointed anteriorly ; and the middle-piece is short and cylindrical, and appears to have a spiral fibre passing round it ; but in different animals the shape of the head and the extent of the middle- piece vary greatly. In the rat the head is long, and is recurved ante- riorly ; it is set obliquely on the middle-piece, which is also of con- siderable extent, and has a closely wound spiral filament encircling it in its whole length. The tail is the longest part of the spermatozoon, and during life is in continual vibratile motion, the action resembling that of the cilia of a ciliated epithelium-cell. The spermatozoa are developed from the small cells or spermato- blasts which form the innermost strata of the seminal epithelium, and are themselves produced by the division of the large cells of the second layer. The nucleus of the spermatoblast forms the head of the sperma- tozoon, while the protoplasm forms first the middle-piece and subse- quently the tail ; but a portion of the protoplasm of each spermato- blast containing a number of small darkly staining particles (seminal granules) appears always to become detached and disintegrated before the spermatozoon is fully mature. 17S THE ESSENTIALS OF HISTOLOGY LESSON XXXV. GENERATIVE ORGANS OF THE FEMALE, AND MAMMARY ' GLANDS. 1. Sections of the ovary of the rabbit. Study the sections with the low power, observing the small and large Graafian vesicles, each enclosing an v>vum, scattered through the stroma. Measure some Graafian vesicles of different sizes ; make a general sketch of a section under the low power. Then sketch carefully two or more of the Graafian vesicles with their contents. 2. Sections across the Fallopian tube. Sketch a section under the low power. 3. Section across the body of the uterus. Observe with the naked eye the thickness of the muscular and mucous coats respectively. Notice the ciliated columnar epithelium lining the organ and extending into the glands of the mucous membrane. Draw a part of the section under the low power. 4. Sections of the mammary gland from an animal killed during lactation. Notice the fat-globules in the alveoli and also in the alveolar cells. Draw an alveolus under the high power. The ovary is a small solid organ, composed of a stroma of fibrous tissue, with many spindle-shaped cells, and also containing, especially near its attachment to the broad ligament, a large number of plain Y^£ Fig. 215. — Section of the ovary of the cat. f 1, outer covering and free border of the ovary ; 1'. attached border ; 2, the central ovarian stroma, presenting a fibrous and vascular structure ; 3, peripheral stroma ; 4. blood- vessels; 5, Graafian follicle? in their earliest stages lying near the surface: 6, 7, 8, more advanced follicles which are embedded more deeply in the stroma ; 9, an almost mature follicle containing the ovum in its deepest part ; 9', a follicle from which the ovum lias accidentally escaped ; 10, corpus luteum. GENERATIVE ORGANS OF THE FEMALE 170 muscular fibres. It is covered by a layer of small columnar epithelium- cells (germinal epithelium, fig. 21G, a), between which are here and there to be seen a few larger spheroidal cells, with large round nuclei (primitive ova, fig. 218, c). In the young subject the epithelium may occasionally dip down into the subjacent stroma. The stroma is beset with vesicles of different sizes, the smallest Fig. 216. — Section of the ovary of an adult hitch. V a, germ-epithelium : b, egg-tubes ; c, c, small follicles ; •/. more b liele; e, discus pro- ligerus and ovum : /, second ovum in the same follicle < this occurs but rarely i : g, outer tunic of the follicle; A. inner tunic; (, membrana granulosa; t, collapsed retro follicle; /, blood-vessels : >«. /". longitudinal and transverse sections of tubes of the paro- varium : y, involuted portion of the germ-epithelium of the surface ; ;, place of the transi- tion from peritoneal to germinal or ovarian epithelium. being near the surface of the organ, the larger ones placed more deeply in the stroma, although, as they increase in size, they may again tend to approach the surface. These vesicles are the Graafian follicles. Each Graafian follicle n2 180 THE ESSENTIALS OF HISTOLOGY lias a proper wall of basement-membrane, strengthened by a layer derived from the stroma, and contains an ovum, surrounded by a number of epithelium-cells. In the smallest follicles the ovum is small, and the epithelium of the follicle is formed of a single layer of cells, which are flattened against the ovum. In somewhat larger follicles the epithelium-cells are in two layers, and these are columnar in shape. In still larger ones, each of these two layers is formed of several strata of cells, and fluid has begun to collect between the layers at one part. Of the two layers, the one which lines the cavity of the follicle is termed the membrana granulosa, while the mass of cells which more immediately surrounds the ovum is known as the discus proligerus. In the largest follicles the fluid has much increased in amount, so that the follicle has become gradually larger and more tense. Finally it reaches the surface of the ovary, and projects from that surface, where it eventually bursts, and the liquor folliculi, with its contained ovum, is set free. This event occurs at about the time of menstrua- tion. 1 Fig. 217. — Semi-diagrammatic representation of a mammalian ovum. (Highly magnified.) zp, zona pellucida ; vi, vitellus ; gv, germinal vesicle ; gs, germinal spot. The ova are large spheroidal cells (fig. 217). When mature, as in the largest Graafian follicles, each ovum is surrounded by a thick transparent striated membrane (zona pellucida). Within this is the protoplasm of the cell (vitellus), filled with fatty and albuminous granules. Lying in the vitellus, generally eccentrically, is the large clear round nucleus (germinal vesicle), which contains an intranuclear network, and usually one well-marked nucleolus [germinal spot). Both the ova and the epithelium of the Graafian follicles are developed 1 Some of the Graafian follicles do not burst, but, after attaining a certain stage of maturity, undergo a process of retrograde metamorphosis and eventually disappear. GENERATIVE ORGANS OF THE FEMALE 181 originally from the germinal epithelium. In the enibryo. this forms a thick layer, covering the fibrous and vascular stroma. After a time solid cords of epithelium-cells, which in some animals are partly tubular (ovarian tubes of Pfliiger), grow down into the stroma, whilst this at the same time grows into the epithelium. The cords presently become broken up by the ingrowths of stroma into small isolated nests of epithelium-cells, each of which may represent a Graafian follicle. To form the ova, some of the germinal epithelium-cells become en- larged, and usually there is one such enlarged cell hi each of the isolated nests. The remaining cells form the epithelium of the follicle (see fig. 218). Fig. 218. — Section' of the ovary <>f a newly born child. (Highly magnified.) a, ovarian or germinal epithelium : b. formation of an ovarian tube ; c, c, primordial ova lying in the germ-epithelium; >m near the fundus. o, epithelium of inner surface; 6, V, uterine glands; c,interglandulai connective ti>-ue ; d, muscular tissue. 184 THE ESSENTIALS OF HISTOLOGY activity, the cells of the alveoli become much enlarged and of a columnar shape, and fatty globules become formed within them (B). These fatty globules appear to become set free by the breaking down of the inner part of the cell, the protoplasm of the cells becoming partially dissolved and Fig. 220. — Alveoli of the mammary gland of the bitch under different conditions of activity. A, section through the middle of two alveoli at the commencement of lactation, the epithelium-cells being seen in profile ; £, an alveolus in full secretory activity. forming the proteid substances of the milk. According to some authors, lymph-corpuscles may also carry fat into the alveoli and there become disintegrated. At the commencement of lactation this disintegration is imperfect, so that numerous cells containing fat-particles appear hi the secretion [colostrum corpuscles). 185 LESSON XXXVI. STRUCTURE OF THE SPINAL CORD. 1. Sections of the spinal cord from the cervical, dorsal, and lumbar regions. [The spinal cord is hardened by being immersed for about a month in bichromate of ammonia solution (2 per cent.) ; the sections are made with a freezing microtome and are stained with aniline blue black. 1 ] Notice the relative extent of the grey as compared with the white matter in the different regions of the cord. In the white matter the stained dots are sections of the axis-cylinders of the longitudinally disposed medullated nerve-fibres ; the tissue between the nerve-fibres is neuroglia. In the grey matter the branched nerve-cells are conspicuous, lying m a reticular sub- stance which is formed of neuroglia together with an interlacement of nerve- fibres and cell-processes. Sketch a section from each region under a low power. Sketch also a small portion of the white substance, two or three nerve-cells, and the central canal with its fining epithelium and surrounding neuroglia under the high power. Measure the diameter of some of the nerve-fibres in the anterior columns, in the lateral columns, and in the posterior columns The spinal cord is composed of grey matter in the centre and of white matter externally. It is closely invested by a layer of connective tissue containing numerous blood-vessels (pia mater), and less closely by two other membranes. One of these is an areolar membrane, re- sembling a serous membrane in general structure, but non -vascular and more delicate in texture {arachnoid). The other, which lines the vertebral canal, is a strong fibrous membrane known as the dura mater. At the middle of the anterior and posterior surfaces the pia mater dips into the substance of the cord in the anterior and posterior median fis- sures, so as to divide it almost completely into two lateral halves. These are, however, united by an isthmus or bridge, which is composed anteriorly of transversely crossing white fibres (white commissure), posteriorly of grey matter (grey commissure), in the middle of which is a minute canal lined by ciliated epithelium (central canal, fig. 221, c\. Each lateral half of the spinal cord contains a crescent of grey matter, which is joined to the corresponding crescent of the opposite side by the grey commissure. Of the two cornua of the crescent the 1 See Appendix. 186 THE ESSENTIALS OF HISTOLOGY posterior is the narrower and comes near the surface of the cord ; opposite to it the bundles of the posterior nerve-roots enter the cord. The bundles of the anterior nerve-roots enter the anterior cornu. The white matter of each half of the cord is subdivided by the passage of the nerve-roots into the cornua into three principal columns — anterior, lateral, and posterior. It is composed of longitudinally coursing medullated nerve-fibres, which in stained sections appear as clear circular areas with a stained dot, the axis-cylinder, near the middle (fig. 222). Fig. 221.— Section of the spinal cord in the lower dorsal region. (Cadiat.) a, e, c, anterior, lateral, and posterior columns ; s, 6', anterior and posterior median fissures. a, 6, e, cells of anterior cornn ; d, posterior cornu and substantia gelatinosa of Rolando; e, central canal : /, veins : . formatio reticu- laris : r'.n -. arciform fibres proceeding from formatio reticularis; »it i,i' fifth nerve; «.<■. nucleus cunea- tus; it. c. external cuneate nucleus; /.,-. funiculus cuneatus : ».,/. nucleus gracilis;/.?, funiculus gracilis; p.mf. rior median fissure; c.c. central canal surrounded by grey matter, in whic-li are, n.XI. nucleus of the spinal accessory, and n.XII. nucleus of the hypoglossal; s.d. superior pyramidal nation. nM. — | am./ (fig. 227, n.g., n.c.), but most of the grey matter of the cornu becomes broken up. by the passage of bundles of nerve-fibres through it, into a reticular formation (f.r), the production of which is already foreshadowed in the upper part of the spinal cord. The central canal of the spinal cord is still seen in the lower part of the medulla oblongata (c. c), but it comes nearer to the posterior median fissure. The grey matter which sur- rounds it contains two well-marked groups of nerve-cells ; the anterior of these is the nucleus of the hypoglossal or twelfth nerve (n. \u. i, the posterior that of the spinal accessory or eleventh i u. xi. I. Instead of the o 194 THE ESSENTIALS OF HISTOLOGY comparatively narrow isthmus which joins the two halves of the spinal cord, a broad raphe now makes its appearance ; this is formed of obliquely and antero-posteriorly coursing fibres, together with some grey matter containing nerve-cells. In a section at about the middle of an olivary body (fig. 228), it will be seen that a marked change has been produced in the form of the medulla and the arrangement of its grey matter, by the opening out of the central canal into the fourth ventricle. This causes the grey matter which below surrounded the central canal to be now spread •vM nX 't nX f.s. p n.a Fig. 228. — Section of the me- dulla OBLONGATA AT ABOUT THE MIDDLE OF THE OLIVARY BODY, i f.l.n. anterior median fissure ; n.a): nucleus axciformis; p, pyramid; XII. bundle of hypoglossal nerve emerging from the surface ; at b it is seen coursing between the pyra- mid and the olivary nucleus, o ; f.a.e. external arciform fibres : n.l. nucleus lateralis ; «, arciform fibres passing towards restiform body partly through the substantia tiuosa. ;/. partly superficial to tbe ascending root of the fifth nerve, o.V. ; X, bundle of vagus root, emerging \f.r. formatio reticularis ; c.r. corpus restiforme, beginning to be formed, chiefly by arciform fibre-. superficial and deep : n.c. nucleus cuneatus; n.g. nucleus gracilis; t. attachment of the ligula; /.s. funiculus solitarius ; n.X. n.X'. two parts of the vagus nucli as; n.XII. hypoglossal nucleus: i,.t. nucleus of the funiculus teres ; n.am. nucleus ambiguus ; /•, r< A, continuation of anterior column of cord : o', o", accessory olivary nuclei ; olivary nucleus ; p.o.l. pe- duuculus olivaa. out at the floor of that ventricle, and the collections of nerve-cells from which the hypoglossal and spinal accessory nerves respectively arose now, therefore, lie in a corresponding situation. At this level, how- ever, the outer group which corresponds with the nucleus of the spinal accessory in the lower part of the medulla has become the nucleus of the vagus or tenth nerve. The nerve-bundles of the roots of these nerves can be seen in the sections coursing through the thickness of the medulla and emerging, those of the hypoglossal (ay/.) just outside the pyramids, those of the spinal accessory and vagus (x.) at the side of the medulla. The two sets of emerging fibres thus appear to sub- divide each lateral half of the medulla into three areas — a posterior, a middle, and an anterior. Of these the posterior is chiefly occupied by the grey matter of the floor of the fourth ventricle, and, with fibres which are passing obliquely upwards and outwards towards the cere- bellum, forming its inferior eras (restiform body, c.r.) ; and in addition there is the continuation upwards of the portions of grey matter forming the nuclei of the funiculus gracilis (n.g.), of the funiculus cuneatus THE MEDULLA OBLONGATA 195 (nx. }, and of the tubercle of Eolaudo {g). The anterior or mesial area is occupied in front by the pyramid [p), and behind this by a reticular formation (reticularis alba, A) composed of longitudinally coursing bundles of fibres interlaced with fibres that are passing obliquely from the opposite side, through the raphe, towards the restiform body (fig. 229, r.a.). The middle area, which lies between the issuing bundles of the two sets of *nerve-roots, consists in its deeper part of a similar XII r.a. Fig. 229. — Part of the reticular formation . formatio reticu- laris ; r, raphe ; s.f, substan- tia ferruginea. Fig. 233. — Transverse section through the upper part of the pons. more than twice the natural .size.) 1 p, transverse fibres of the pons ; py, py. bundles of the pyramids : a, boundary line between the tegmental part of the pons and its ventral part ; /'. oblique fibres of the fillet, passing towards LP. longitudinal fibres of the fillet; /'./-. formatio reticularis: p.l. posterior longitudinal bundle : i.c.p. superior cerebellar peduncle: cm. superior medullary velum : b, grey matter of tho lingula; c 4, fourth ventricle : in the grey matter which bound* it laterally are seen, <'.!'. the descending root of the fifth nerve, with its nucleus. ,«./. sub- stantia ferruginea, ij.c. group of cells continuous with the nucleus of the aqueduct. I The details of this and of several of the preceding figures are filled in under a somewhat higher magnifying power than that used for tracing the outlines. STRUCTURE OF THE MESENCEPHALON 199 in the grey matter of the floor of the ventricle but nearer the middle line, and the seventh from a nucleus which lies in the formatio reticularis, and from which the fibres of the nerve pass backwards to the floor of the ventricle, then longitudinally upwards for a short distance, finally bending forwards and downwards and emerging between the transverse fibres at the sides of the pons. At the upper part of the pons (fig. 233) the fourth ventricle narrows considerably towards the Sylvian aqueduct, and behind and on either Fig. 234. — Sections through the origin of the fourth nerve. | A, transverse section at the place of emergence of the nerve-fibres. B, oblique section carried along the course of the bundles from the nucleus of origin to the place of emer- gence. Aq, Sylvian aqueduct, with its surrounding grey matter; IV. the nerve-bundles emerging; IV. decussation of the nerves of the two sides; IV". a round bundle passing downwards by the side of the aqueduct to emerge a little lower down ; n.lV. nucleus of the fourth nerve. /, fillet ; s.e.p., superior cerebellar peduncle; d.Y. descending root of the fifth nerve ; pi, posterior longitudinal bundle ; r, raphe. side of it two considerable masses of longitudinal white fibres make their appearance. These are the superior crura of the cerebellum (s.c. p.), and they tend as they pass upwards gradually to approach the middle line (fig. 234 A), across which in the region of the posterior pair of the corpora quadrigemina they pass, decussating with one another, to the formatio reticularis of the opposite side (fig. 235, A). Fig. 235. — Outline of two sections across the mesencephalon. (Natural size.") A, through the middle of the inferior corpora quadrigemina. B, through the middle of the superior corpora quadrigemina. cr. crusta ; s.n. substantia nigra ; t, tegmentum ; s, Sylvian aqueduct, with its surrounding grey matter ; e.q. erey matter of the corpora qua- drigemina ; l.g. lateral groove : pj. posterior longitudinal bundle ; d.V. descending root of the fifth nerve ; i.e.p. superior cerebellar peduncle : /'. fillet; n.TII. its nucleus ; ///. third nerve. The dotted circle in B indicates the situation of the tegmental nucleus. Iii sections across the mesencephalon (fig. 235), the upward con- tinuity of the parts which have thus been described in the lower parts of the nerve-centres, can still hi great measure be traced. 200 THE ESSENTIALS OF HISTOLOGY The Sylvian aqueduct (s), with its lining of ciliated epithelium, re- presents the central canal of the cord and the fourth ventricle of the medulla. In the grey matter which surrounds it {central grey matter) there is seen in all sections of the region a group of large nerve-cells lying anteriorly on each side of the middle line, close to the reticular formation. From this group the root-bundles of the fourth nerve arise at the lower part of the mesencephalon and pass obliquely backwards and downwards around the central grey matter, decussating with those of the opposite side to emerge just above the pons Varolii (fig. 234). Higher up the bundles of the third nerve spring from the continuation of the same nucleus (fig. 235, n. ///.), and these pass forwards and down- wards with a curved course through the reticular formation, to emerge at the mesial side of the crusta. The reticular formation of the pons is continued up into the mes- encephalon, and is here known as the tegmentum. It is composed as before of longitudinal and transverse bundles of fibres with much grey matter intermingled. The transverse fibres include the decussating fibres of the superior crura of the cerebellum {s.c.j).), and the fibres of the fillet (/), which are passing in an oblique manner from the raphe to the side of the mesencephalon, to reach eventually the grey matter of the prominences of the corpora quadrigemina. The pyramid bundles of the pons are continued upwards on each side into the crusta (cr.). This forms a mass of longitudinally coursing bundles of fibres lying on the ventral aspect of each half of the mesencephalon, and diverging above into the internal capsule of the cerebral hemisphere. The crusta is separated from the tegmentum by a layer of grey matter containing a number of very deeply pigmented nerve-cells which give it the name of substantia nigra (s.n.) The crusta and tegmentum, together with the intervening substantia nigra, constitute the cms cerebri. The prominences of the corpora quadrigemina are formed mainly of grey matter containing numerous small nerve-cells. From each a bundle of white fibres (brachium) passes upwards and forwards towards the geniculate bodies, eventually joining the optic tract of the same side. On the other hand, each of the prominences receives from below fibres of the fillet, which are themselves traceable into the posterior part of the lateral column of the medulla oblongata. 201 LESSON XXXVIII. STRUCTURE OF THE CEREBELLUM AND CEREBRUM. 1. Section's of the cerebellum across the direction of the laminae and vertical to the surface. 2. Section across the whole of one hemisphere of the cerebrum of a monkey or man, passing through the middle of the third ventricle. 3. Vertical sections of the cerebral cortex, one from the ascending frontal gyrus, another from the occipital lobe, and a third across the hippocarnpal gyrus and hippocampus. 4. Transverse sections of the olfactory tract and bulb. In all these preparations make sketches under a low power of the general arrangement of the grey and white matter, and also of the nerve-cells in the grey matter. Sketch some of the details under a high power. The cerebellum is composed of a white centre, and of a grey cortex, both extending into all the folds or lamina?, so that when the lamina? are cut across, an appearance is presented of a white arborescence Fig. 236. — Section through one of the hemispheres of the cerebellum, to show the medullary centre and its prolongations into the LAMELLA covered superficially by grey matter. The white matter is in largest amount in the middle of each cerebellar hemisphere (fig. 236). There is here present also a peculiar wavy lamina of grey matter, similar to that in the olivary body, and known as the nucleus dentatus (ii.d.). 202 THE ESSENTIALS OF HISTOLOGY Other isolated grey nuclei He in the white matter of the middle lobe. The grey matter of the cerebellum consists of two layers (fig. 237). The inner one (that next the white centre) is composed of a large number of very small nerve-cells (granule layer, d). The outer layer Fig. 237. — Section of cortex of cere- bellum. a, pia mater ; b, external layer ; c, layer of cor- puscles of Purkinje ; d, inner or granule layer ; -e, medullary centre. Fig. 238. — Processes op the corpus- cles OF PURKINJE, CONNECTED BY THEIR FINER BRANCHES WITH COR- PUSCLES OF THE OUTER LAYER OF THE CEREBELLAR CORTEX. (Highly magnified.) a, a, processes of the corpuscles of Purkinje ; b, a branch from one of them, which is con- nected with two of the corpuscles of the outer layer ; c, c, scattered branched cor- puscles of this layer. (b) is thicker, and is formed of neuroglia, with rounded and angular small nerve-cells and neuroglia-cells scattered through it. Into its outer part processes of the pia mater conveying blood-vessels pass vertically, and there are also in this part a number of long taper- ing cells, somewhat like the Mullerian fibres of the retina. Lying STRUCTURE OF THE CEREBRAL CORTEX 203 between the two layers of the grey matter is an incomplete stratum of large flask- shaped cells (cells of Purkinje, c). Each of these gives off from its base a fine process, which be- comes the axis-cylinder of one of the medullated fibres of the white centre, while from the opposite pole of the cell large ramified processes spread out into the superficial layer of the grey matter, and some of these processes become con- nected with its small nerve- cells (fig. 238). Structure of the cerebrum. The grey matter of the ce- rebral cortex is described as being composed of a number of layers, but they are not sharply marked off from one another. The following are usually distinguished (fig. 239). 1. Most externally a thin stratum containing a few scat- tered cells, probably neuro- glia-cells. In the most super- ficial part of this layer imme- diately under the pia mater, is a very thin stratum of medullated nerve-fibres. 2. A layer of closely set small pyramidal nerve-cells several deep. This layer is also thin. 3. A thick layer contain- ing larger and longer pyra- midal cells less closely set. These cells are largest in the deepest part of the layer ; and in the region of the motor centres of the brain some of them are of very large size, and are collected into small groups. 204 THE ESSENTIALS OF HISTOLOGY 4. A thin layer of numerous small irregular angular cells. 5. A rather thicker layer of small scattered cells, many of a fusi- form shape. This layer lies next to the white centre. In the island of Eeil this stratum is considerably developed, and is somewhat sepa- J _^- ' [V'/V* _ ' ' '" '"!V ',' ■ ti'ri Fig. 240.— Section across the hippocampus major, dentate fissure, dentate fascia and fimbria. Gh, part of the gyros hippocampi or uncinate convolution ; Fd, fascia dentata, or dentate convo'ution : between them is the dentate fissure : J'i, fimbria, composed of longitudinal fibres here cut across; 1, 2, medullary centre of the hippocampal gyrus prolonged around the hippocampus, //, as the so-called alveus, into the fimbria; 3, layer of large pyramidal cells ; 4, their processes ( stratum radiatum ) ; 5. reticular neuroglia (stratum laciniosum ) ; 6, superficial medullary lamina, involuted around the dentate fissure : * *, termination of this lamina, the fibres here running longitudinally ; 7, superficial neuroglia of the fascia dentata ; *, ring of small cells within this (stratum granulosum). rated from the rest of the grey matter by a layer of white substance. It is known as the claustrum. From the white centre bundles of medullated nerve-fibres pass in vertical streaks through the deeper layers of the grey matter, to lose STRUCTURE OF THE OLFACTORY TRACT AND BULB 205 themselves amongst the pyramidal cells of the more superficial layers, with processes from which they are probably continuous. In the hippocampal region a remarkable difference of structure manifests itself (fig. 240). The superficial layer of neuroglia and the white stratum, which overlies it as a thin band in other parts of the cortex, are in this region both very strongly marked (5, 6 ), the neuroglia layer having a very distinctly reticular aspect, and being in part beset with small cells. All the rest of the thickness of the grey matter appears to be mainly composed of, or at least to contain, long conical cells (3, 4), the distal processes or apices of which are prolonged into fibres which lose themselves in the superficial layer of neuroglia. The pyramidal cells rest upon the white centre, here known as the atoms (l), which is the part of the hippocampus seen within the ventricle, and which is prolonged externally into the fimbria (Fi), where its fibres be- come longitudinal in direction. In the dentate gyrus (fascia dentata, fig. 240, Fd) the pyramidal cells are arranged in an irregularly radiating manner, occupying the centre of the convolution, and surrounded by a ring of closely packed small cells (*), external to these being the relatively thick layer of superficial neuroglia (7). The olfactory tract is an outgrowth of the brain which was ori- ginally hollow, and remains so in many animals ; but in man the cavity has become obliterated, and the centre is occupied by neuroglia, containing, however, no nerve-cells (fig. 241). Outside the central Fig. 241. — Section across the olfactory tract. neuroglia lies the white or medullary substance, consisting of bundles of longitudinal white fibres. Most externally is a thin superficial layer of neuroglia. The olfactory bulb (fig. 242) has a more complicated structure. Dorsally there is a flattened ring of longitudinal white bundles enclosing neuroglia (l, 2, 3), as in the olfactory tract, but below this ring a number of layers are superadded as follows : 1. A granule layer (fig. 242, 4), characterised by the presence of a 206 THE ESSENTIALS OF HISTOLOGY large number of small nerve-cells with reticulating bundles of meclul- lated nerve fibres running between them. 2. An intermediate nerve-cell layer (6) consisting of neuroglia, in which small pyramidal nerve-cells are embedded. This layer is also traversed by medullated nerve-fibres, and is partly separated from the granule layer by irregular clefts (5). 3. The layer of olfactory glomeruli (7) consists of rounded nests of small ganglion-cells, which appear to give origin to the olfactory nerve- fibres. These pass between the glomeruli to enter the close plexus of non-medullated nerve-fibres which lies directly over the cribriform plate. 4. This is the layer of olfactory nerve-fibres (8), and from it branches (*) pass directly downwards to the nasal fossas. Fig. 242.— Section across a part of the olfactory bulb. 1, 3. bundles of very fine transversely cut nerve-fibres, forming tbe flattened medullary ring, enclosing the central neuroglia, 2; 4, granule-layer: 5. loose tissue with irregular spaces (? lymphatic); (;. intermediate layer; 7, layer of olfactory glomeruli, t, "ft ; 8, layer of olfactory nerve-fibres. Basal ganglia. — Besides the grey matter of the cerebral cortex the cerebral hemispheres conceal in their deeper parts certain other masses of grey substance (fig. 243). The principal of these are the corpus striatum (nucleus caudatus, c, and nucleus lenticularis, str) and optic thalamus (th). Between them run the bundles of white fibres which are STRUCTURE OF THE CORPUS STRIATUM 207 passing upwards from the crus cerebri, forming a white lamina termed the internal capsule. Above the level of these nuclei the internal capsule expands into the medullary centre of the hemisphere (see also figs. 244 and 245, with their description). Fig. 243. — Frontal section- through the brain and skull made whilst FROZEN. h c.c. corpus callosum ; below its middle part the septum lucidum. and below that again the fornix ; L V, Lateral ventricle : ih, thalamus : between the two thalaroi the third ventricle j- jeen : below the- thalamus is the subthalamic prolongation of the tegmental region, and below this the prolongation of the crusta ; str, lenticular nucleus of the corpus striatum ; c, caudate nucleus of the same ; between c. th, and sir, the internal capsule i~ seen ; outside tlr i- the thin grey band of the claustrum. and outside this again the island of Beil at the bottom of the Sylvian fissure : n.a. nucleus amygdala- : immediately within this is the optic tract seen in section ; p, pituitary body ; B, body of the sphenoid bone ; sa, subarachnoid space ; v, villi of the arachnoid. The nucleus caudatus of the corpus striatum is composed of a reddish-grey neuroglia containing both moderately large and small multi- polar nerve-cells. It receives fibres from the part of the internal capsule which separates it from the nucleus lenticularis, and next the lateral ventricle it is covered by a thin layer of neuroglia, and over this by the epithelium of the cavity. The nucleus lenticularis, which corresponds in position internally with the island of Reil externally, is divided by two white lamina? into three zones. It is separated from the nucleus caudatus and optic thala- mus by the internal capsule (figs. 244, 245, ic), which consists of the bundles of medullary fibfes which are passing between the white centre of the hemisphere and the crus cerebri ; it receives on its inner side many white fibres from the capsule, and these impart to it a radially striated aspect. Many of the nerve-cells of the nucleus lenticularis contain yellow pigment. 208 THE ESSENTIALS OF HISTOLOGY Fig. 244. — Section across the optic thalamus and corpus striatum in the region of the middle commissure. (Natural size.) th, thalamus ; a, e, i, its anterior, external, and internal nuclei respectively ; tc, its external white laver ; m. c. middle commissure ; v. 3. third ventricle ; a small part is also seen below the middle commissure ; c. e. corpus callosum ; /', fornix, separated from the third ventri- cle and thalamus by the velum interpositum. In the middle of this are seen the two veins of Galen and the choroid plexuses of the third ventricle ; and at its edges the choroid plexuses of the lateral ventricles, v. I. : t.s. taenia semicircularis ; cr, forward prolongation of the crusta passing laterally into the internal capsule, i. c. ; s. t. r. subthalamic prolonga- tion of the tegmentum, consisting of (1 ) the dorsal layer, (2) the zona incerta, and (3) the corpus subthalamicum ; «. ti. substantia nigra ; n. c. nucleus caudatus of the corpus stria- tum ; n. I. nucleus lenticularis ; f the iris, >een- prom the pos- terior SCRFAl K AFTER REMOVAL OF THE UVEAL PIGMENT. «, sphincter muscle ; b, dilatator muscle of the pupil. Fig. 255. — Vessels of the choroid, ciliary pro< i 3SES 3 AND IRIS OF A CHILD. ( 10 diameters.) a, capillary network of the posterior part of the choroid, ending at h, theora serrata; e, arteries of the corona ciliaris, supplying the ciliary | and passing into the iris,e;/, the ca- pillary network close to the pupillary margin of the iris. similar structure, but its pigment-cells often contain coloured pigment. Besides the homogeneous connective tissue, with numerous elastic fibres and blood-vessels of which it is chiefly composed, it contains two sets of plain muscular fibres. The one set forms the sphincter muscle (fig. 245, a \, which encircles the pupil, the other set consists of a flattened layer of radiating fibres which extend from the attachment of the iris Dearly to the pupil, lying close to the posterior surface and constituting the dilatator muscle (b). The back of the iris is covered by a thick layer of pigmented epithelium i uvea i continuous with the epithelium of the pars ciliaris retinae. The blood-vessels of the iris converge towards the pupil (fig. 255, C). 220 THE ESSENTIALS OF HISTOLOGY Near the pupil the small arteries form a small anastomotic circle, from which capillaries arise and pass still nearer the pupil, around which they form a close capillary network. A large number of nerve-fibres are distributed to the choroid and iris, probably going chiefly to the muscular tissue (ciliary muscle and sphincter and dilatator iridis). The retina consists of the eight layers shown in the accompanying figure (fig. 256), numbered as they occur from within out. Outer or choroidal surface. 8. Layer of pigment-cells. Laver of rods and cones. Membrana limitans externa. 6. Outer nuclear laver. 5. Outer molecular layer. 4. Inner nuclear layer. \W- 3. Inner molecular layer. 2. Layer of nerve-cells. 1. Layer of nerve-fibres. . . Membrane limitans interna. Inner surface. Fig. 2.J6. — Diagrammatic section <>f the human retina. The inner surface of the retina, which is smooth, rests upon the hyloid membrane of the vitreous humour. It is formed of the united bases of the fibres of Miiller, which will be afterwards described. The layer of nerve-fibres is formed by the expansion of the STRUCTURE OF THE RETINA 221 optic nerve after it has passed through the coats of the eye (fig. 257). At its entrance it forms a slight eminence (colliculus nervi opiici). The nerve-fibres lose their medullary sheath on reaching the retina. The layer becomes gradually thinner in the anterior part of the retina. <£fr&™^z* Ve 'YmAr Fig. 257. — Section through the coats of the eyeball at the point of ENTRANCE OF THE OPTIC NERVE. (Toldt.) Ve. dural sheath ; Vm, arachnoidal sheath, and 17. pia-matr.il sheath of the optic nerve, with lymphatic spaces between them : 0, ". funiculi of the nerve : L, lamina cribrosa ; A, central artery : S, sclerotic : Ch, choroid : R, retina. The small letters refer to the various parts of the retina, b being the layer of rods and cones, and t that of nerve-fibres. The layer of nerve-cells, or ganglionic layer, is composed of large nerve -cells somewhat like the cells of Purkinje of the cerebellum, and having on the one side a fine axis-cylinder process prolonged into a nerve-fibre, and on the other a thick branching process, the ramifica- tions of which become lost in the next layer. The inner molecular layer is comparatively thick, and has an appearance very like the neuroglia of the grey matter of the nerve- centres. A few nuclei are scattered through it, and it is traversed by the processes of the nerve-cells and of the inner granules, as well as by the fibres of Muller. The inner nuclear layer is mainly composed of bipolar cells con- taining large nuclei {inner granules). The processes of these cells extend on the one hand inwards through the inner molecular layer, probably to join with nerve-fibres or with the processes of the gan- glion-cells, whilst the other process is directed outwards, and is con- nected with the extremity of a rod or cone fibre. Besides these bipolar cells, there are other inner granules which are different in character, being devoid of processes and resting on, or even embedded in, the 222 THE ESSENTIALS OF HISTOLOGY inner molecular layer, with the formation of which they are probably connected. Others, which are larger and more rounded, are applied to the outer molecular layer. The fibres of Midler have nucleated enlargements hi the inner nuclear layer. The outer molecular layer is thin, and is composed of flattened and branched cells, the ramified cell-processes being united into a close network (fig. 258). Fig. 258. — Branched cells with the uniting feltwork of fibres from the outer molecular layer of the horse's retina. As far as the outer molecular layer the retina may be said to con- sist of nervous elements, but beyond this layer it is formed of modified epithelium-cells. The outer nuclear layer and the layer of rods and cones are com- posed of elements which are continuous through the two layers, and they should properly, therefore, be described as one. It may be termed the neural or sensory epithelium of the retina (fig. 260, G and 7). The elements of which the neural epithelium consists are elongated, nucle- ated cells of two kinds. The most numerous, which we may term the rod-elements, consist of peculiar rod-like structures (rods proper) set closely side by side, and each of which is prolonged internally into a fine varicose fibre (rod-fibre) which swells out at one part of its course into a nucleated enlargement. The rod proper consists of two segments, an outer cylindrical and transversely striated segment, which during life has a purplish-red colour, and an inner slightly bulged segment, which in part of its length is longitudinally striated. The nucleus of the rod-element often has, in the fresh condition, a transversely shaded aspect (fig. 259). The cone-elements are formed of a conical taper- ing external part, the cone proper, which is directly prolonged into a nucleated enlargement, from the farther side of which the cone- fibre, considerably thicker than the rod-fibres, passes inwards, to ter- minate by an expanded base at the outer molecular layer. The cone proper, like the rod, is formed of two segments, the outer of which, much the smaller, is transversely striated, the inner, bulged segment STRUCTURE OF THE RETINA 223 Fig. 259. — Diagrammatic representation of the nervous and epithelial ELEMENTS OF THE RETINA. 1 to 5, nervous elements. 6, 7, epithelial elements. The designation of the numbers is the same as in fig. 346. The extent of the molecular layers is indicated merely by linear shading. 224 THE ESSENTIALS OF HISTOLOGY being longitudinally striated. The inner ends of the rod- and cone- fibres are believed to be connected with processes from the inner granules, and through these with the nerve-cells and nerve-fibres. In birds, reptiles, and amphibia, a small oil-globule, often brightly coloured red, yellow, or green, is found in the inner segment of each cone, and other variations of structure are met with in animals. The cones are most numerous at the back of the retina ; they are fewer in number, and the rods are proportionally more numerous, towards the anterior part. tM. I. Fig. 260. — Pigmented epithelium of the human retina. (Highly magnified.) a, cells seen from the outer surface with clear lines of. intercellular substance between ; b, two cells seen in profile with fine offsets extending inwards ; c, a cell still in connection with the outer ends of the rods. Fig. 261. — A fibre of Muller from the HUMAN RETINA, ISOLATED. w ?° 6, base of the fibre ; n, its nucleus ; m.e.l. mem- brana limitans externa; e.m.l. external mo- lecular layer. The ■pigmentary layer is the most external part of the retina. It is formed of hexagonal epithelium-cells (fig. 260), which are smooth exter- nally where they rest against the choroid, but are prolonged internally into fine filaments which extend between the rods. The pigment-granules, STRUCTURE OF THE RETINA 225 many of which are in the form of minute crystals, He in the inner part of the cell, and after prolonged exposure to the light they are found extending along the cell-processes between the rods (b, c), their function being probably connected with the restoration of the purple colouring matter which has been bleached by the light. Fibres of Midler. — The fibres of Miiller (fig. 261 ) are long stiff fibres which pass through several of the retinal layers. Commencing at the inner surface of the retina by expanded bases which unite with one another to form the so-called, internal limiting membrane (fig. 356), the fibres pass through all the layers in succession, until they reach the outer nuclear layer. Here they branch and expand into a sort of reti- cular tissue which serves to support the fibres and nuclei of the rod- and cone-elements. At the bases of the rods and cones, this sustentacular tissue ceases, being here bounded by a distinct margin which has been called the external limiting membrane [m. e. I.), but delicate sheaths have been described passing from it round the bases of the rods and cones. Each Miillerian fibre, as it passes through the inner nuclear layer, has a nucleated enlargement (n), indicating the original cell nature of the fibre. There are two parts of the retina which call for special description. The macula lutea (yellow spot, fig. 268), with its central fovea, lies in the visual axis, and is the part of the retina which is most immedi- Fig. 262.— Vertical section through the macula lutea and fovea centralis ; diagrammatic. 1, nerve-layer ; 2, ganglionic layer ; 3. inner molecular : 4, inner nuclear ; and 5, outer molecu- lar layers : 6, outer nuclear laj er, the inner part with only cone-flbres forming the so-called external fibrous layer ; 7, cones and rods. ately concerned in direct vision. It is characterised first by its greater thickness (except at the fovea), secondly by the large number of ganglion-cells, which are all distinctly bipolar (2), and thirdly by the large number of cones it contains as compared with the rods. In the Q 226 THE ESSENTIALS OF HISTOLOGY central fovea itself there are no rods, and the cones are very long and slender ; moreover, all the other layers become gradually thinned down almost to complete disappearance, so that the middle of the central fovea is the thinnest part of the retina. Since there are few rods, the outer nuclear layer | (J i loses in great measure its appearance of being composed of closely packed nuclei, and the cone-fibres are very distinct. The direction of all the fibres is very oblique in this part of the retina. The pars ciliaris retina which commences at the ora serrata, where the retina proper abruptly ends, is composed of two epithelial layers (fig. 263 j, and has no nervous structures. Of the two layers, the Fig. 263. — A small portion of THE CILIARY PART OF THE RE- TINA. (350 diameters.) 1, pigment-cells ; 2, columnar cells. external is a thick stratum of pigmented epithelium formed of rounded cells and continuous with the pigmentary layer of the retina on the one hand, and with the uvea of the iris on the other ; the inner is a layer of columnar cells each containing an oval nucleus. The retina contains but few blood-vessels. The artery enters and the vein leaves it in the middle of the optic nerve. The larger vessels ramify in the nerve-fibre layer, and there are capillary networks in this layer and in the inner nuclear layer. There are peri-vascular lymphatic spaces around the veins and capillaries. The neural epithe- lium receives no blood-vessels, but is nourished from the vessels of the choroid. Structure of the lens. The lens is a laminated fibrous body en- closed by a transparent elastic capsule into which, around the circum- Fig. 2G4. — Section through the margin of the rabbit's lens, showing the TRANSITION OF THE EPITHELIUM INTO THE LENS-FIBRES. ference, the fibres of the suspensory ligament are inserted. Immedi- ately within the capsule, in front and at the sides, there is a layer of cubical epithelium termed the epithelium of the capsule, but at the margin of the lens the cells become longer and pass by a gradual transition into the lens-fibres (fig. 264). The fibres which compose the lens are long and riband-shaped, with finely serrated edges (fig. 265, A) ; STRUCTURE OF THE LENS AND VITREOUS HUMOUR 227 in transverse section they appear prismatic I B i. Many of the superficial fibres are nucleated (c), the lens-fibres having originally been developed by the elongation of epithelium -cells. Fig. 265. — Fibres of the crystalline lens. (350 diameters.) A, longitudinal view of the fibres of the lens from the ox, showing the serrated edges. B, transverse section of the fibres of the leus from the human eye. C, longitudinal view of a few of the fibres from the equatorial region of the human* lens. Most of the fibres in C are seen edgeways, and, towards 1. present the swellings and nuclei of the 'nuclear zone ; ' at 2, the flattened sides of two fibres are seen. The vitreous humour is composed of soft gelatinous tissue, appa- rently structureless when examined in the fresh condition, but contain- ing a few scattered amoeboid cells, the processes of which are often long and varicose, and the cell-bodies distended by large vacuoles. The hyaloid membrane, which invests the vitreous humour, is homogeneous and structureless except in the region of the ciliary processes, where it is fibrous in structure, forming the zonule of Zinn and spreading out into the suspensory ligament of the lens. 02 228 THE ESSENTIALS OF HISTOLOGY LESSON XLI. STRUCTURE OF THE OLFACTORY MUCOUS MEMBRANE AND OF THE EXTERNAL AND MIDDLE EAR. 1. Vertical sections of the olfactory mucous membrane. The sections may be carried either across the middle turbinate bone, after decalcification in 0"2 per cent, chromic acid, or across the upper part of the nasal septum. Make a sketch under the low power. Notice the difference in the character of the epithelium in the olfactory and respiratory parts of the membrane. 2. Teased preparation of the epithelium of the olfactory mucous mem- brane. Apiece of the membrane is placed quite fresh in osmic acid (1 per cent.) for a few horns, and is then macerated for two days or more in water. The epithelium is broken up in dilute glycerine ; the cells easily separate from one another on tapping the cover-glass. Notice the two kinds of cells. Sketch some of the cells under a high power. 3. Sections of the external ear (these have been already studied for the cartilage, Lesson XII.) 4. Sections across the cartilaginous part of the Eustachian tube. Sketch under the low power. 5. Preparation of the membrana tympani. A piece of the membrane, stained with hematoxylin, and mounted flat in Canada balsam. Determine the composition of the membrane — i.e. the several layers com- posing it — by focussing carefully with the high power. STRUCTURE OF THE OLFACTORY MUCOUS MEMBRANE. The olfactory region of the nasal fossae includes the upper and middle turbinate processes and the upper third of the septum. It is covered by a soft vascular mucous membrane of a yellow colour in man. T\\e epithelium oi the olfactory mucous membrane (figs. 266, 267 lis very thick and is composed of long tapering cells, set closely side by side and bounded superficially by a cuticular lamina, through which the free ends of the cells project. The cells are of two kinds : 1. Long narrow spindle-shaped or bipolar cells consisting of a larger part or body (b), containing the nucleus, and of two processes or poles, one (c) straight and cylindrical and extending to the free surface, the other \d) very delicate and varicose, looking not unlike a nerve-fibril and extending THE OLFACTORY MEMBRANE 229 down to the corium. The position of the nuclear enlargement varies, and with it the relative length of the two processes. The distal or free process terminates in a small clear projection, which passes beyond the cuticular membrane ; in amphibia, reptiles, and birds, and perhaps in some Fig. 2G6.— Cells and terminal nerve-firres of the olfactory region. (Highly magnified.) 1, from the frog ; 2, from man ; a, epithelial cell, extending deeply into a ramified process : i: olfactory cells ; e. their peripheral rods ; e, their extremities, seen in I to be prolonged into tine hair? ; : canalis re- unieus ; c.c. caual of the cochlea. Fig. 270. — View of the interior of the left osseous labyrinth. 2* The bony wall of the labyrinth is removed superiorly and externally. 1, fovea hemi- elliptica: 2,foveahemisphaerica; 3. common opening of the superior and posterior semi- circular canals ; 4, opening of the aqueduct of the vestibule ; 5, the superior, 6, the posterior, and 7, the external semicircular canals; 8, spiral tube of the cochlea; 9, scala tympani ; 10, scala vestibuli. The membranous semicircular canals and the utricle and saccule are composed of fibrous tissue, which is adherent along one side to the endosteum of the bony canal ; from the opposite side bands of fibrous tissue pass across the perilymph. Within the fibrous membrane is a thick clear tunica propria, which, in the semicircular canals, forms papillary elevations in the interior of the tube (figs. 271, 272). The places of entrance of the nerve-fibres into the ampulla?- are marked by a transverse, inwardly projecting ridge {crista), in the saccule and utricle by a thickening of the tunica propria (macula). The epithelium at these places is formed of columnar cells (fig. 273;, which are surmounted by long, stiff, tapering hairs {auditor)/ hairs, fig. 273, h), and to these hair-cells the axis-cylinders of the nerve-fibres pass directly (fig. 274) ; they are therefore — like the rod- and cone- elements of the retina, the bipolar cells of the olfactory membrane, and the gustatory cells of the taste-buds — sensory or neural epithelium-cells. Between them are a number of thin and somewhat rigid nucleated cells [fibre-cells of Eetzius, fig. 274,/), which rest upon the basement- membrane, and are connected at their free extremity with a cuticular membrane, through which the auditory hairs project. The auditory hairs do not project free into the endolymph, but into a soft mucus-like substance, of a dome-like form, in the ampullae (fig. 273), and which in the saccule and utricle has a mass of calcareous particles (otoliths) embedded in it. 234 THE ESSENTIALS OF HISTOLOGY Fig. 271. — Section of one of the human semicircular canals. (Magnified.) 1, osseous wall ; 2, fibrous bands with included blood-vessels, united at 3 with the periosteum ; 4, membranous canal with its three layers; 5, short fibrous bands (with intervening spaces) uniting the membranous canal firmly to the neriosteum ; 6, union of its outermost layer with the periosteum. Fig. 272.— Section of membranous semicircular canal. (Much magnified.) 1, outer fibrous laver; 2, tunica propria ; 3, 6, papilliform projections with epithelial covering; 5, fixed side of the canal, with very thin tunica propria without papilke; 7, fibrous bands passing to periosteum. STRUCTURE OF THE COCHLEA 235 Fig. 273. — Longitudinal section of an ampulla through the crista acustica. amp, cavity of the ampulla; sec, semicircular canal opening out of it; c, connective tissue attached to the wall of the .nembranous ampulla and traversing the perilymph ; e, e, flattened epithelium of ampulla; h, auditory hairs projecting from the columnar cells of theauditory epithelium into the cupula, tup. term. ; v, blood-vessels ; n, nerve-fibres entering the base of the crista and passing into the columnar cells. Fig. 274. — Auditory epithelium from the macula acustica of the saccule of an alligator. ( Highly magnified.) c,e, columnar hair-cells ;/./', fibre-cells ; n, nerve-fibre, losing its medullar; sheath and passing to terminate in the columnar auditory cells ; h, auditory hair ; h', base of auditory hairs, split up into fibrils. 236 THE ESSENTIALS OF HISTOLOGY The cochlea consists of a bony tube coiled spirally around an axis, which is known as the columella (fig. 275). The tube is divided longitudinally by a partition which is formed partly by a projecting Fig. 275.— Vertical section of the cochlea of a calf. n sp.l Fig. 276.— Vertical section of the first turn of the human cochlea. (Retzius.) s.r. «cala vestibuli: iJ. Bcala tympani; h.f. r-annl of the cochlea: sp.l. spiral lamina: n. nerve-fibres; I.sp. spiral ligament; sir.c. stria vascularis ; t.tp, spiral groove-; A', section of Reissner's membrane: /. Umbos laminae spiralis; MA. membrana tectoria; AC. tunnel of Corti ; b.m. basilar membrane ; h.i., h.f.. internal and external hair-cells. lamina of bone (spiral lamina), partly by a flat membrane (basilar membrane), into two parts or scales; the upper (supposing the cochlea resting base downwards) being termed the scala vestibuli (fig. 276, s.v.) STRUCTURE OF THE COCHLEA 237 the lower the scala tympani (s.t.) ; the latter is closed at its larger end by the membrane of the fenestra rotunda. The scahe are lined by endosteum, and are filled with perilymph, continuous with that of the rest of the osseous labyrinth at the commencement of the scala vestibuli ; they communicate at the apex by a small opening, the hclicotrema. The scala vestibuli does not occupy the whole of that part of the bony tube of the cochlea which is above the partition. Its outer third is cut off by a delicate connective-tissue membrane (membrane of Eeissner, fig. 276, B), which springs from near the end of the spiral lamina, and passes upwards and outwards to the outer wall, thus separating a canal (DC) triangular in section, which is lined by epithe- lium, and represents the membranous labyrinth of the cochlea (canal of the cochlea). Canal of the cochlea. The floor of the canal of the cochlea is formed (1) of the extremity of the spiral lamina, which is thickened above by a peculiar kind of connective tissue, forming an overhanging projection known as the limbics (fig. 270, I) ; (2) of the basilar mem- brane (b.m.t, which stretches across from the end of the bony lamina to the outer wall, and is attached to this by a projection of reticular connective tissue termed the spiral ligament \l.sp.) The basilar membrane is composed of stiff, straight fibres, which extend from within out, and themselves rest on a homogeneous stratum. It is covered below by a layer of connective tissue continuous with the endosteum of the scala tympani ; above the modified epithelium which forms the organ of Corti rests upon it. It becomes gradually broader in the upper turns of the cochlea (rather more than twice as broad in the uppermost as in the lowermost turn), and its constituent fibres become therefore gradually longer. The organ of Corti consists of the following structures : 1. The rods of Corti, two series (inner and outer) of stiff, striated fibres of a peculiar shape, the inner rods somewhat like a human ulna, the outer like a swan's head and neck (fig. 277). They rest by one ex- tremity i the foot) on the basilar membrane a short distance apart, and Fig. 277. — A r.uic <>f bods of Cohti, from thk. rabbit's cochlea, i>' side VIEW. (Highly magnified.) b, b, basilar membrane ; i.r. inner roil : e.r. outer rod. The nucleated protoplasmic masses at the feet are also shown. are inclined towards one another, their larger ends ( heads i being jointed together ; the series of rods thus enclose a sort of tunnel, the floor of which is formed by a part of the basilar membrane. Close to their 238 THE ESSENTIALS OF HISTOLOGY feet may usually be seen the remainder of the cells from which they have been formed. The inner rods are narrower and rather more numerous than the outer. Each outer rod has a process which extends outwards and is known as the phalangeal process. This forms part of— 2. A reticular lamina (fig. 279, l.r.), which is a cuticular structure extending like a wire-net over the outer epithelium-cells of the organ of Corti, and is composed of two or three series of stiff fiddle-shaped rings (phalanges) cemented together in such a manner as to leave square or oblong apertures through which the hair-cells (see below) project. 3. The outer hair-cells placed external to the rods of Corti. These are epithelium-cells of columnar shape, arranged in three or four series b— ~.-3 Fig. 278. — Section of the organ of Corti of the dog. sqq a, «'. end of spiral lamina ; 6, c, middle (homogeneous) layer of the basilar membrane : u, ves- tibular (striated > layer: (.tympanal (connective-tissue) layer ; d, blood-vessel : /, nerves in spiral lamina ; ./. epithelium of spiral groove ; h, nerve-fibres passing towards inner hair- cells, i, £ ; I. auditory hairlets on inner hair-cells ; /. /', lamina reticularis ; m, heads of the rods of Corti. jointed together ; n, base of inner rod- ; ,,. base of outer rod : p. q, r, outer hair-cells ; t, lower ends of hair-cells ; ic, nerve-fibrils passing across the tunnel of Corti ; z, cells of Deiters. (fig. 278, p, q, r). The free extremity of the cell is surmounted by a bundle of short auditor)/ hairs, and projects through one of the apertures in the reticular lamina ; the fixed extremity is prolonged into a stiff cuticular process (fig. 280, pf), which is attached to the basilar membrane. Between them are other supporting cells which are tapered in the same manner, resting by their larger end upon the basilar membrane, and prolonged above into a cuticular process which is attached to the reticular lamina {cells of Deiters, fig. 278, z). They are said by Waldeyer to be sometimes united with the outer hair-cells, so as to form double cells. 4. The inner hair-cells (fig. 278, i), placed internal to the rods of STRUCTURE OF THE COCHLEA 239 Fig. 279. — Semi-diagram- matic view of part of the basilar membrane and tl'xnki. of corti of the rabbit, from above AND THE SIDE. (Much magnified.) I. limbus ; Cr. extremity or crest of limbus with tooth-like pro- jections ; b.b. basilar membrane; sp.l. spiral lamina with, p, perforations for transmission of nerve-fibres. In part of the spiral lamina here represented the nerve-fibres are left, and are supposed to be seen through the upper layer of that lamina, con verging to three of the perfora- tions : to the right, in the section of the lamina, they are shown occupyingacaual.orcleft. in the osseous substance; i.r. fifteen of the inner rods of Corti ; h.i. their flattened heads seen from above; e.r. nine outer rods of Corti : h.e. their heads, with the phalangeal processes ex- tending out ward from them and forming, with the two rows of phalanges, the lamina reticu- lar!-. I.r. On the left of the figure the connective-tissue fibres and nuclei of the unier- most layer of the basilar mem- brane are seen through the upper layers. Portions of the basilar processes of the outer hair-cells remain attached here and there to the membrane at this part. Fig. 280. — An outer hate-cell in connection with its basilar process. From the guinea-pig. (Highly magnified.) h, one or two hairlets which have remained attached to the cell : 6. bulged lower end of cell : p. basilar process, protoplasmic above, but becoming cutioular below and slightly expanded at the extremity,/, which is broken away from the basilar membrane. 240 THE ESSENTIALS OF HISTOLOGY Corti. They form a single series of columnar cells surmounted by auditory hairs, lying in close apposition to the inner rods. The rest of the epithelium-cells have no important characteristics. They are long and columnar next the outer hair-cells, but soon diminish in size, becoming cubical, and in this form they are continued over the outer wall of the cochlear canal. Here they cover a very vascular membrane (stria vascularis, fig. 27G, sir), which is frequently pigmented ; its capillary blood-vessels may even penetrate between the epithelium - cells. Internal to the inner hair-cells the epithelium also soon becomes cubical ; it is prolonged in this form over the limbus of the spiral lamina. The epithelium of Eeissner's membrane is of the pavement variety. The membrana tectoria Ifig. 276, M.t.) is a soft, fibrillated structure, which is attached along the upper surface of the limbus, and lies like a pad over the organ of Corti. It thins out towards the distal margin, here becoming somewhat reticular, and, according to Eetzius, attached to the lamina reticularis. In sections it usually appears raised a short distance above the auditory hairs, but it is possible that it may rest upon them during life. Fig. 281. — General view of the mode of distribution of the cochlear nerve, all the other parts having been removed. The fibres of the cochlear branch of the auditory nerve enter the base of the columella, and run in canals through its substance, being gradually deflected outwards as they pass upwards into the spiral lamina, at the base of which they swell out into a ganglionic cord (spiral ganglion i. After traversing the spiral lamina they emerge in bundles, and the fibres then, having lost their medullary sheath, pass into the epithe- lium of the inner hair-cell region. Here some of them are connected directly with the inner hair-cells, whilst others pass in the form of delicate fibrils across the tunnel of Corti, to become connected with the outer hair-cells (fig. 278j. APPENDIX. General Methods of Preserving and Hardening Tissues and Organs. 1 — The fluids which are most commonly used are alcohol, chromic acid solution (1 in 500), picric acid solution (saturated), bichromate of potash solution (2 per cent.), Midler's fluid (bichromate of potash 2£ parts ; sulphate of sod* 1 part ; water 100 parts), and bichromate of ammonia (2 per cent.) The following are the methods of hardening the several tissues and organs which are found to give the best general results : — Tissue or Organ Bladder Blood-vessels Brain Elastic ligament Embryos . Eye . Eyelids Ganglia Heart Injected organs Intestine . Kidney Lachrymal gland Larynx Liver Lung Mammary gland Marrow of bone Muscular tissue, striated „ non-striated Nerve (Esophagus ( )vary Pancreas . Retina Salivary glands . Sclerotic and cornea Skin . Hardening Fluid Chromic acid. Alcohol, or bichromate of potash. Bichromate of ammonia. Bichromate of potash. Chromic acid or picric acid. Midler's fluid. Alcohol. Picric acid. Alcohol, or bichromate of potash. Alcohol. Distend with chromic acid. Bichromate of potash. Alcohol. Chromic acid. Bichromate of potash. Distend with chromic acid. Alcohol. Alcohol. Bichromate of potash. Chromic acid. Picric acid. Distend with chromic acid. Chromic acid. Alcohol. Midler's fluid. Alcohol. Alcohol, or Midler's fluid. Alcohol. 1 Methods of preparation required for special purposes are given in the Lessons. R 242 THE ESSENTIALS OF HISTOLOGY Tissue or Organ Hardening Fluid Spinal cord Spleen Stomach . Suprarenal capsule . Tendon and ligament Testis Thymus gland . Thyroid gland . Tongue Tonsils Trachea Ureter Uterus Bichromate of ammonia. Bichromate of potash. Distend with chromic acid or with alcohol. Alcohol. Alcohol. Alcohol. Alcohol. Alcohol. Bichromate of potash. Alcohol. Chromic acid. Chromic acid. Chromic acid. Tissues to be hardened in alcohol may either be placed at once in strong spirit (90 per cent, alcohol), or the hardening may be effected gradually, the tissue being placed first in weak spirit (50 per cent.) for twenty-four hours, then in somewhat stronger, and finally in strong spirit or absolute alcohol. They are ready for cutting after having been twenty-four hours in strong spirit. For tissues that are to be hardened in l per cent, chromic acid, an immer- sion of from 7 to 14 days is generally necessary ; they may then be washed with water, and placed in alcohol for preservation and to complete the pro- cess of hardening. Organs placed in bichromate of potash or Midler's fluid are ready for sections in a fortnight or three weeks ; they may, however, be left for a much longer time in those fluids without deterioration. With picric acid the hardening process is generally complete in two or three days; the organs should then be washed for some hours under a tap and transferred to spirit. The hardening of the brain and spinal cord in bichromate of ammonia takes three or four weeks. These organs should not be left too long in the solution, since they are apt to become brittle, but sections should be prepared from them as soon as ready. In no case should the pieces of tissue to be hardened be too thick for the fluid readily to penetrate to every part. Embedding of Hardened Tissues, and Preparation of Sections.— Sections are most advantageously made with some form of microtome. It is generally needful to support the hardened tissue whilst it is being cut, and with this object it is embedded in some fatty or other substance which is applied to it in the fluid condition and becomes solid on standing. The embedding sub- stance can either simply enclose the tissue, or the tissue may be soaked in it : the latter method is the one most commonly employed. The embedding substance chiefly used is paraffin. Embedding in paraffin. — Before being soaked in melted paraffin, the piece of tissue is stained with borax-carmine or hematoxylin, dehydrated by absolute alcohol, and is then soaked in turpentine. From turpentine it is transferred to melted paraffin, which should not be too hot. and soaked in this for an hour or more, according to thickness. It is then placed in any desired position in a paper tray or on the microtome and surrounded by melted APPENDIX 243 paraffin. When cold, thin sections can be cut, the paraffin dissolved out by turpentine, and the sections mounted. Preparation of frozen sections. — The bichromate solutions are the best fluids to use for preserving tissues which are to be frozen in place of being embedded. The tissue in such cases should not be put into alcohol, but merely requires to be dipped in strong gum before being placed upon the freezing microtome. Portions of the central nervous system need to be soaked in giun to which a little syrup has been added. Staining and mounting of sections. — The fluids most commonly employed for the staining of sections are : — 1. A dilute watery solution of hematoxylin and alum ; 2. A solution of carmine ; 3. A solution of picro-carminate of am- monia. The time of immersion in the staining fluid varies according to the strength of the fluid and the mode by which the tissue has been hardened. The necessity of staining sections may be avoided if the piece of tissue is stained in bulk before embedding. For this purpose a carmine solution is mostly used, on account of its penetrative power, that known as borax-carmine bein? the best. The tissue must be left in it for twenty-four hours or more, and then placed in acidulated alcohol. An alcoholic solution of magenta can be used for staining in bulk ; from this the tissue goes into a small quantity of oil of cloves or into turpentine, and, after being soaked with this, into the melted paraffin. If the tissues have not been stained in bulk, the following is the order of transference of the sections (they are supposed, if cut from paraffin, to have been freed from this by immersion in turpentine) :— 1. From turpentine to absolute alcohol (5 minutes). 2. From alcohol to distilled water iA minute). 3. From distilled water to hematoxylin or carmine (5 minutes or more). 4. From hematoxylin to distilled water (h minute). 5. From distilled water to alcohol (2 or 3 minutes). 6. From alcohol to oil of cloves il minute). 7. From oil of cloves to Canada balsam. If the tissues have already been stained in bulk, the sections are simply mounted in Canada balsam after the paraffin used for embedding has been dissolved away from them in turpentine. Creosote-shellac method of mounting. — Friable sections, such as sections of small embryos, and ribands of sections such as are cut with many micro- tomes, are mounted in the following way : — The slide is smeared with a solu- tion of shellac in creosote, the sections are placed in this and warmed so as to melt their paraffin. They are thus fixed by the shellac, and the slide can be immersed in turpentine to remove the paraffin, and the sections then covered in Canada balsam. For this method the tissue should always have been pre- viously stained in bulk. Solutions employed for Staining: — 1. Solution of hatmatoxyhn in-icatcr. — Rub together in a mortar 10 grammes of powdered alum and 5 grammes of extract of hematoxylin with 25 cubic centimeters of 70 per cent, alcohol, gradually adding 100 cubic centimeters of distilled water. Decant into a bottle and add a drop or two of ammonia. Let the mixture stand a few days, occasionally shaking it. For staining, add two or three drops to a watch-glass full of distilled water, and filter if necessary. 2. Grrenacher'8 hematoxylin. — To 150 cubic centimeters of a saturated 244 THE ESSENTIALS OF HISTOLOGY solution of alum in water, add 4 cubic centimeters of saturated solution of hematoxylin in alcohol. Let the mixture stand 8 days, then decant, and add 25 cubic centimeters of glycerine, and 25 cubic centimeters of methylic alcohol. 3. Kleinenberg'e hcematoxylin. — This serves better for staining in bulk. Saturate 70 per cent, alcohol hist with calcium chloride and then with alum, and after filtration add six to eight volumes of 70 per cent, alcohol. Take a freshly prepared saturated solution of hematoxylin in absolute alcohol, and add it drop by drop to the above mixture until it is of a distinct purplish colour. This solution improves on keeping. It may if necessary be diluted with more of the mixture "When hematoxylin solutions become red instead of blue, a trace of ammonia will restore the requisite colour. 4. Carminute of ammonia. — Prepared by dissolving carmine in ammonia and allowing the excess of ammonia to escape by slow evaporation. The salt should be allowed to dry and be dissolved in water as required. 5. Picro-carminate of ammonia (pier o -carmine). — To a saturated solution of picric acid add a strong ammoniacaJ solution of carmine, until a precipitate begins to form. Evaporate on the water-bath to |th ; filter from the sedi- ment and evaporate the filtrate to dryness. Make a 5 per cent, solution of the residue, diluting further as required. 6. Borax-carmine. — a. Dissolve 4 grammes borax and 3 grammes carmine in 100 cubic centimeters of warm water. Add 100 cubic centimeters of 70 per cent, alcohol, filter and let stand. This solution improves on keep- ing. It is useful for staining in bulk. /3. Boil - 5 gramme carmine and 1 gramme borax in 100 cubic centi- meters water. Filter and add acetic acid drop by drop until the original violet colour becomes crimson ; then filter once more. This solution is used for staining sections. After staining with borax-carmine, the tissue should in all cases be placed in 70 per cent, alcohol containing 5 drops of hydrochloric acid to 100 cubic centimeters. 7. Magenta. — This may be kept in solution in alcohol (0*5 to 1 per cent.) For fresh tissues and for sections to be mounted in glycerine, an excellent staining fluid is obtained by adding one or two drops to a watch-glass of water. For sections to be mounted in Canada balsam a solution in oil of cloves is used. This is best made by adding a drop of the alcoholic solution to a little oil of cloves in a watch-glass : the sections after being stained are washed in spirit of turpentine. 8. Gentian violet. — Mix 20 cubic centimeters water with 10 cubic centi- meters alcohol and 10 cubic centimeters glycerine, and add to the mixture 10 drops of a 1 per cent, solution of gentian violet in alcohol and 10 drops of a 25 per cent, solution of formic acid in water. This solution gives excellent results with fresh tissues, especially with epithelium. 9. Safranin. — A saturated alcoholic solution is used for staining cell- nuclei. The tissue elements having been fixed by dilute chromic acid or by alcohol, small shreds or thin sections are placed for 12 to 24 hours in a little of the solution, mixed with half its bulk of water. The shreds are rinsed in absolute alcohol (which must contain no trace of free acid) until the colour is APPENDIX 245 washed out from everj'thing except the nuclei ; they are then at once trans- ferred to turpentine, and from this are mounted in Canada balsam. 10. Aniline blue-black. — Dissolve 1 gramme of aniline blue-black in a mixture of 30 parts of water with 20 of alcohol. This serves for staining the central nervous system either in bulk or in sections. 11. Staining with chloride of gold. — a. Cohnheim's method. — Place the fresh tissue for from 30 to 60 minutes in j per cent, solution of chloride of <_r • > 1 < I : then wash and transfer to a large quantity of water just acidulated with acetic acid. Keep for 2 or 3 days m the light in a warm place. 3. LovriVi method. — Place small pieces of the fresh tissue in a mixture of 1 part of formic acid to 2 to 4 parts of water for h to 1 minute ; then in 1 per cent, chloride of gold solution for 10 to 15 minutes ; then back again into the formic acid mixture for 24 hours and then into pure formic acid for 24 hours more. After removal from the gold, and whilst in the acid, the tissue must be kept in the dark. y. Ranvier's method. — Immerse in lemon-juice for 5 to 10 minutes, then wash with water and place in 1 per cent, gold chloride solution for 20 minutes. Then treat either as in Cohnheim's or in Lowit's method. 12. Staining with nitrate of silver. — Wash the fresh tissue with distilled water; immerse in ^ to 1 per cent, nitrate of silver solution for 5 to 10 minutes ; rinse with distilled water and expose to bright sunlight either in water, alcohol, or glycerine. Mounting Solutions : — 1. Saline solution. — A - 6 per cent, solution of common salt is used in place of serum for mounting fresh tissues for imme- diate examination. 2. A mixture of glycerine and water in equal parts. 3. Farrant's solution. — Take a mixture of equal parts of glycerine and saturated watery solution of arsenious acid, and stir guru arabic with it until a thick syrupy rluid is formed. Filter. 4. Canada balsam, from which the volatile oils have been driven off by heat, dissolved in benzole. 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All letters pertaining to the Business Department of these journals should be addressed exclusively to Lea Brothers & Co., 706 and 708 Sansom Street, Philadelphia. HARTSHOJRNE, HENRY, A. M., M. D. f LL. D., Lately Professor of Hygiene in the University of Pennsylvania. A Conspectus of the Medical Sciences ; Containing Handbooks on Anatomy, Physiology, Chemistry, Materia Medica, Practice of Medicine, Surgery and Obstetrics. Second edition, thoroughly revised and greatly improved. In one large royal 12mo. volume of 1028 pages, wit b. 477 illustrations. Cloth, $4.25; leather, $5.00. The object of this manual is to afford a conven- I industry and energy of its able editor.— Boston lent work of reference to students during the brief Medical and Surgical. Journal, Sept. 3, 1874. moments at their command while in attendance We can Bay. with the strictest truth, that it is the upon medical lectures. It is a favorable sign that | best work of the kind with which we areacquaint- it has been found necessary, in a short space of ed. It embodies in a condensed form all recent time, to issue a new and carefully revised edition, contributions to practical medicine, and is there- The illustrations are very numerous and unusu- fore u-eful to every busy practitioner throughout ally clear, and each part "seems to have received our country, besides being admirably adapted to its due share of attention. We can conceive such the use of students of medicine. The book is a work to be useful, not only to students, but to faithfully and ably executed.— Charleston Medical practitioners as well. It reflects credit upon the Journal. April, 1875. STUDENTS 9 SERIES OF HAJSUALS. A Series of Fifteen Manuals, for the use of Students and Practitioners of Medicine and Surgery, written by eminent Teachers or Examiners, and issued in pocket-size 12mo. volumes of 300-540 pages, richly illustrated and at a low price. The following vol- umes are now ready: Bell's Comparative Physiology and Anatomy, Gould's Surgical Diagnosis, Robertson's Physiological Physics, Bruce' s Materia Medica and Therapeutics, Power's Human Physiology, Clarke and Lockwood's Dissectors' Manual, Ralfe's Clinical Chemistry, Treves' Surgical Applied Anatomy, Pepper's Surgical Pathology, and Klej n t& of Histology. The following are in press : Bellamy's Operative Surgery, Pepper's Forensic Medicine, and Curnow's Medical Applied Anatomy. For separate notices see index on last page. SERIES OF CLINICAL MANUALS. In arranging for this Series it has been the design of the publishers to provide the profession with a collection of authoritative monographs on important clinical subjects in a cheap and portable form. The volumes willcontain about 550 pages and will be freely illustrated by chromo-lithographs and woodcuts. The following volumes are just ready: Butlin on the Tongue; Treves on Intestinal Obstruction; and Savage on M uroses; The following are in active preparation: Hutchinson on Syphilis; Bryant on the Breast; Morris on Sm ases of the Kidney; Broadbent on the Puke; Owen on Surgical diseases of Children; Lucas on Diseases of the Urethra; Marsh on Diseases of the Joints, Pick on Fractures and Dislocations, and Ball on the Rectum and Am/.-:. For separate notices see index on last page. NEILL, JOHN, 31. D., and SMITH, F. G., M. D. f Late Surgeon to the Penna. Hospital. Prof, of the Institutes of Med. in the Univ. of Penna. An Analytical Compendium of the Various Branches of Medical Science, for the use and examination of Students. A new edition, revised and improved. In one large royal 12mo. volume of r. Wkst.uacott. The dissections jointly by the Author and Dr. Carter. With an Introduction on General Anatomy and Development by T. Holme*, M.A., Surgeon to St. George's Hospital. Edited by T. Pickering Pick, F. B. C. S., Surgeon to and Lecturer on Anatomy at St. George's Hospital, London, Examiner in Anatomy, Royal College of Surgeons of England. A new American from the tenth enlarged and improved London edition. To which is added the second American from the latest English edition ot Landmarks, Medical and Surgical, by Luther Holdkn, F. R. C. S., author of "Human Osteology," "A Manual of Dissections," etc. In one imperial octavo volume of L023 pages, with 564 large and elaborate engravings on wood. Cloth, $6.00 ; leather, $7.00 ; very handsome half Russia, raised bands, $7.50. This work covers a more extended range of subjects than is customary in the ordinary text-bonks, giving not only the details necessary for the student, but also the application to those details to the practice of medicine and surgery. It thus forms both a guide for the learner and an admirable work of reference for the active practitioner. The engravings form a special feature in the work, many of them being the size of nature, nearly all original, and having the names of the various parts printed on the body of the cut, in place of figures of reference with descriptions at the foot. They thus form a complete and splendid series, which will greatly assist the student in forming a clear idea of Anatomy, and will also serve to refresh the memory of those who may find in the exigencies of practice the necessity of recalling the details of the dissecting-room. Combining, as it does, a complete Atlas of Anatomy with a thorough treatise on systematic, descriptive and applied Anatomy, the work will be found of great service to all physicians who receive students in their offices, relieving both preceptor and pupil of much labor in laying the groundwork of a thorough medical education. Landmarks, Medical and Surgical, by the distinguished Anatomist, Mr. Luther Holden, has been appended to the present edition as it was to the previous one. This work gives in a clear, condensed and systematic way all the information by which the practitioner can determine from the external surface of the body the position of internal parts. Thus complete, the work, it is believed, will furnish all the assistance that can be rendered by type and illustration in anatomical study. This well-known work comes to us as t!io latest There is probably no work used so universally American from" the tenth English edition. As its by physicians and medical students as this one. title indicates, it has passed through many hands It is deserving of the confidence that they repose and has received many additions and revisions, in it. If the present edition is compared with that The work is not susceptible of more improvement, issued two years ago, one will readily see how Taking it all in all, its size, manner of make-up, much it has been improved iu that time. Many its character and illustrations, its general accur- j pages have been added to the text, especially in a -v of description, its practical aim, and its per- those parts that treat of histology, and many new spicuity of style, it is the Anatomy best adapted to cms have been introduced and old ones modified, the wants of the student and practitioner. — Medical — Journal of the American Medical Association, Sept. Record, Sept. l">, IS : l, 1883. Also for sale separate — HOLDEN, LUTHER, F. R. C. 8., "nd the Foundling Hospitals, London. Landmarks, Medical and Surgical. Second American from the latest revised English edition, with additions by W. \\\ Keen, M. P., Professor of Artistic Anatomy in the Pennsylvania Academy of l lie Fine Arts, formerly Lecturer on Anatomy in the Phila- delphia School of Anatomy. In one handsome 12mo. volume of 148 pages. ( loth, $1.00. This little book is all that can be desired within almost to learn it by heart, [t teaches diagnosis by intents will he found simply in- external examination, ocular and palpable, of the valuable to the young surgeon or physician, since body, with such anatomical and physiological facts they bring before him Buch data a- he requiresat as directly bear on the subject ft is eminently every examination of a patient. It is written in the student's and young practitioner's book.— Phy- language so clear and concise that one ought - Nov. 1881. WILSON, ERASMUS, F. R. 8. A System of Human Anatomy, General and Special. Edited by W. H. G( bki cht, M. I >., Professor of General and Surgical Anatomy iii the Medical College of Ohio. In one large and handsome octavo volume of 61(5 pages, with oi'7 illustrations. Cloth. $4.00; leather, $5.00. SMITH, II. II, M. />., and HORNER, WM. E..M.I)., Prof, of Surgery in the Univ. of Penna., etc. Latt Prof, of AnaU in the Univ. of Penna. An Anatomical Atlas, Illustrative of the Structure of the Human Body. In one large imperial octavo volum>, of 200 pages, with ., F. R. S., Prof essor of Anatomy and Ph A Directory for the Dissection of the Human Body. In one 12mo. volume of 178 pages. ( loth, $1.25. 6 Lea Brothers & Co.'s Publications — Anatomy. ALLIEN, HARRISON, 31. !>., Professor ol Physiology in the University of Pennsylvania. A System of Human Anatomy, Including Its Medical and Surgical Relations. For the use of Practitioners and Students of Medicine. With an Intro- ductory Section on Histology. By E. O. Shakespeare, M. D., Ophthalmologist to the Philadelphia Hospital. Comprising 813 double-columned quarto pages, with 380 illustrations on 109 full page lithographic plates, many of which are in colors, and 241 engravings in the text. In six Sections, each in a portfolio. Section I. Histology. Section II. Bones and Joints. Section III. Muscles and Fasces:. Section IV. Arteries, Veins and Lymphatics. Section V. Nervous System. Section VI. Organs of Sense, of Digestion and Genito-Urinary Organs, Embryology, Development, Teratology, Superficial Anatomy, Post-Mortem Examinations, and General and Clinical Indexes. Price per Section, each in a handsome portfolio, $3.50 ; also bound in one volume, cloth $23.00 ; very handsome half Russia, raised bands and open back, $25.00. For sale by subscription only. Apply to the Publishers. Extract from Introduction. It is the design of this book to present the facts of human anatomy in the manner best suited to the requirements of the student and the practitioner of medicine. The author believes that such a book is needed, inasmuch as no treatise, as far as he knows, contains, in addition to the text descriptive of the subject, a systematic presentation of such anatomical facts as can be applied to practice. A book which will be at once accurate in statement and concise in terms ; which will be an acceptable expression of the present state of the science of anatomy ; which will exclude nothing that can be made applicable to the medical art, and which will thus embrace all of surgical importance, while omitting nothing of value to clinical medicine, — would appear to have an excuse for existence in a country -where most surgeons are general practitioners, and where there are few general practitioners who have no interest in surgery. It is to be considered a study of applied anatomy ' care, and are simply superb. There is as much in its widest sense — a systematic presentation of ; of practical application of anatomical points to such anatomical facts as can be applied to the j the every-day wants of the medical clinician as practice of medicine as well as of surgery. Our to those of the operating surgeon. In fact, few author is concise, accurate and practical in his general practitioners will read the work without a statements, and succeeds admirably in infusing feeling of surprised gratification that so many an interest into the study of what is generally con- points, concerning which they may never have sidered a dry subject. The department of Histol- thought before are so well presented for their con- ogy is treated in a masterly manner, and the sideration. It is a work which is destined to be ground is travelled over by one thoroughly famil- the best of its kind in any language. — Medical far with it. The illustrations are made with great Record, Nov. 25, 1882. CLARKE, W. B., F.R. C.S. & LOCKWOOD, C. B., F.R. C.S. Demonstrators of Anatomy at St. Bartholomew's Hospital Medical School, London. The Dissector's Manual. In one pocket-size 12mo. volume of 396 pages, with 49 illustrations. Limp cloth, red edges, $1.50. Just ready. See Students' Seiies of Manuals, page 3. This is a very excellent manual for the use of the part, are good and instructive. The book is neat student who desires to learn anatomy. The meth- . and convenient. We are glad to recommend it.— ods of demonstration seem to us very satisfactory. : Boston Medical and Surgical Journal, Jan. 17, 1884. There are many woodcuts which, for the most TREVES, ERELJERLCK, F. R. C. S., Senior Demonstrator of Anatomy and Assistant Surgeon at the London Hospital. Surgical Applied Anatomy. In one pocket-size 12mo. volume of 540 pages, with 61 illustrations. Limp cloth, red edges, $2.00. Just ready. See Students' Series of Manuals, page 3. He has produced a work which will command a I quickened by daily use as a teacher and practi- larger circle of readers than the class for which it tioner, has enabled our author to prepare a work was written. This union of a thorough, practical which it would be a most difficult task to excel. — acquaintance with these fundamental branches, I The American Practitioner Feb. 1884. curnow, john, Yld., f. r7of., Professor of Anatomy at King's College, Physician at King's College Hospital. Medical Applied Anatomy. In one pocket-size 12mo. volume. Preparing-. See Students' Series of Manuals, page 3. BELLA3IY, EDWARD, F. R. C. S., Senior Assistant-Surgeon to the Charing-Cross Hospital, London. The Student's Guide to Surgical Anatomy : Being a Description of the most Important Surgical Eegions of the Human Body, and intended as an Introduction to operative Surgery. In one 12mo. volume of 300 pages, with 50 illustrations. Cloth, $2.25. HARTSHORNE'S HANDBOOK OF ANATOMY HORNER'S SPECIAL ANATOMY AND HISTOL- AND PHYSIOLOGY. Second edition, revised. | OGY. Eighth edition, extensively revised and In one royal 12mo. volume of 310 pages, with 220 i modified. In two octavo volumes of 1007 pages, woodcuts. Cloth, $1.75. with 320 woodcuts. Cloth, $6.00. Lea Brothers & Co.'s Publications — Physics, Physiol., Anat. 7 DRAPER, JOHN C M. JO., LL. !>., Professor of Chemistry in the University of the City of New York. Medical Physics. A Text-book for Students and Practitioners of Medicine. In one octavo volume of 734 pages, with 376 woodcuts, mostly original. Cloth, $4. Just ready . From the Preface. The fact that a knowledge of Physics is indispensable to a thorough understanding of Medicine has not been as fully "realized in this country aa in Europe, where the admirable works of Desplats and Gariel, of Robertson and of numerous German writers constitute a branch of educational literature to which we can show no parallel. A full appreciation of this the author trusts will be sufficient justification for placing in book form the sub- stance of his lectures on this department of science, delivered during many years at the University of the City of New York. Broadly speaking, this work aims to impart a knowledge of the relations existing between Physics and Medicine in their latest state of development, and to embody in the pursuit of this object whatever experience the author has gained during a long period of teaching this special branch of applied science. Certainly we have no text-book as full as the ex- and it is one of the most valuable scientific cellent one he has prepared. It begins with a trc en to the medical profession for a statement of the properties of matter and energy, number of years. It is profusely and handsomely After these the special departments of physics are illustrated. The work should have a place upon explained, acoustics, optics, heat, electricity and every physician's library shelf. — Maryland M magnetism, closing with a section on electro- Journal,. Jn\v IS, 1885. q. biology. The applications of all these to physiology This is the only work with which we are ac- and medicine are kept constantly in view. The quainted in which physics is treated with reference text is amply illustrated and the many difficult to medicine. Preceptors who are axious that their points of the subject are brought forward with re- pupils should have a scientific knowledge of med- markable clearness and ability. — Medical and Surg- iciue, should make this work a textbook, and re- order, July 18, 1885. q. quire a thorough study of it. — C Jdical The volume from beginning to end teems with News, July 18, 1885. q." useful information. Take the book as a whole robertsow, j. McGregor, m. a., m. b., ead Demonstrator of Physiology, University of Glasgow. Physiological Physics. In one 12mo. volume of 537 pages, with 219 illustra- tions. Limp cloth, $2.00. Just ready. See Students' Series of Manuals, page 3. The title of this work sufficiently explains the ments. It will be found of great value to the nature of its contents. It is designed as a man- practitioner. It is a carefully prepared book of ual for the student of medicine, an auxiliary to reference, concise and accurate, and as such we his text-book in physiology, and it would be particu- heartily recommend it.— Journal of the American larly useful as a guide to his laboratory experi- Medical Association, Dec 6, 1884. DALTON, JOHN a, M. D., Professor Emeritus of Physiology in the College of Physicians and Surgeons, New York. Doctrines of the Circulation of the Blood. A History of Physiological Opinion a:: ry in regard to the Circulation of the Blood. In one handsome 12mo. volume of 293 pages. Cloth, $2. Just ready. Dr. Dalton's work is the fruit of the deep research revolutionized the theories of teachers, than the of a cultured mind, and to the busy practitioner it discovery of the circulation of the Hood. This cannot fail to be a source of instruction. It will explains' the extraordinary ini - to all inspire him with a feeling of gratitute and admir- medical historians. The volume before us is one ation for those plodding workers of olden times, of three or four which have been written within a who laid the foundation of the magnificent temple few years by American physicians. It is in several of medical scienci te. The volume, though small in size, is one of the most creditable con- In the progress of physiological study no fact tribntions from an American pen to medical 1, f greater moment, none more completely that has appeared. — Med. & Surg. Rep., Dec. 6, 1884. BY THE SAME AUTHOR. The Topographical Anatomy of the Brain. In three very handsome quarto volumes comprising 178 pages of descriptive text. Illustrated with 48 full page photo- graphic plates of Brain Sections, with a like number of explanatory plates, as well as many woodcuts through the text. BELL, F. JEFFREY, M. A., Professor of Comparative Anatomy at King's College, London. Comparative Physiology and Anatomy. In one 12mo. volume of 561 pages, with 229 illustrations. Limpcloth, $2.00. Justready. See S> «ls, page3. ELLIS, GEORGE VINJEM, Emeritus Professor of Anatomy in University College, London. Demonstrations of Anatomy. Being a Guide to the Knowledge of the Human Body by Dissection. From the eighth and i idon edition. In one very handsome octavo volume of 716 pages, with 249 illustrations. Cloth, $4.25; leather, | ROBERTS, JOHX Ji.. A. M., M. />., Prof, of Applied Anat. and Oper. Surg, in Phila. Polyclinic and Coll. for Graduates in Medicine. The Compend of Anatomy. For use in the dissecting-room and in preparing for examinations. In one 16mo. volume of 19G pages. Limp cloth, 75 cents. 8 Lea Brothers & Co.'s Publications — Physiology, Chemistry. DALTOX, JOIIN C, 31. D., I ■ rieions and Surgeons, Neio York, etc. A Treatise Oil Human Physiology. Designed for the use of Students and Practitioners of Medicine. Seventh edition, thoroughly revised and rewritten. In one very handsome octavo volume of 722 pages, with 252 beautiful engravings on wood. Cloth, f>5.00; leather, $6.00; very handsome half Russia, raised hands, $6.50. The merits of Professor Dalton's text-book. his more compact form, yet its delightful charm is re- smooth and pleasing style, the remarkable clear- tained, and no subject is thrown into obscurity. DOSS of his descriptions, which leave not a chapter l Altogether this edition is far in advance of any obscure, his cautions judgment and the general previous one, and will tend to keep the profession correctness of his facts, are perfectly known. They posted as to the most recent additions to our have made his text-book the one most familiar physiological knowledge. — Michigan Medical News, to American students. — Med, Record, Match 4, 1882. April, 1882. Certainly no physiological work has ever issued j One can scarcely open a college catalogue that from the press that presented its subject-matter in does not have mention of Dalton's Physiology as a clearer and more attractive light. Almost every the recommended text or consultation-book. For page bears evidence of the exhaustive revision American students we would unreservedly recom- that has taken place. The material is placed in a mend 1 »r. Dalton's woTlt.-Va. Med. Monthly, July, *82. FOSTER, 3IICHAEL, M. JD., JF. bVs., Prelector in Physiology and Fellow of Trinity College, Cambridge, England. Text-Book of Physiology. Third American from the fourth English edition, with notes and additions by E. T. Reichert, M. D. In one handsome royal 12mo. volume of 908 pages, with 271 illustrations. Cloth. $3.25; leather, $3.75. Just ready. Dr. Foster's work upon physiology is so well- to know and what may be passed over by them as known as a text-book in this country, that it needs not important. From the beginning to the end, physiology is taught in a systematic manner. To this third American edition numerous additions, corrections and alterations have been made, so that in its present form the usefulness of the book will l>e found to be much increased. — Cincinnati Mtdical News, July 1885. but little to be said in regard to it. There is scarcely a medical college in the United States where it is not in the hands of the students. '1 hp author, more than any other writer with whom we are acquainted, seems to understand what portions of the science are essential for students POWER, HEXRY, 31. B., F. R. C. S., Examiner in Physiology, Royal College of Surgeons of England. Human Physiology. In one handsome pocket-size 12mo. volume of 396 pages, with 47 illustrations. Cloth, $1.50. See Students' Series of Manuals, page 3. The prominent character of this work is that of judicious condensation, in which an able and suc- cessful effort appears to have been made by its accomplished author to teach the greatest number of facts in the fewest possible words. The result is a specimen of concentrated intellectual pabu- lum seldom surpassed, which ought to be care- fully ingested and digested by every practitioner who desires to keep himself well informed upon this most progressive of the medical sciences. The volume is one which we cordiallv recommend to every one of our readers. — The American Jour- nal of the Medical 8cit nees, October, 1884. This little work is deserving of the highest praise, and we can hardly conceive how the main facts of this science could have been more clearly or concisely stated. The price of the work is such as to place it within the reach of all, while the ex- cellence of its text will certainly secure for it most favorable c mmendation — Cincinnati Lancet and Clinic, Feb. 16, 1884. CARPENTER, W3L B., 31. D., F. R. S., F. G. S., F. L. S., Registrar to the University of London, etc. Principles of Human Physiology. Edited by Henry Tower, M. B., Lond., F. R. C. S., Examiner in Natural Sciences, University of Oxford. A new American from the eighth revised and enlarged edition, with notes and additions by Francis G. Smith, M. D., late Professor of the Institutes of Medicine in the University of Pennsylvania. In one very large and handsome octavo volume of 1083 pages, with two plates and 373 illus- trations. Cloth, $5.50; leather, $6.50; half Russia, $7. FOTVXES, GEORGE, Ph. I). A Manual of Elementary Chemistry; Theoretical and Practical. Em- bodying "Watts' Inorganic Chemistry. New American edition. In one large royal 12mo. volume of over 1000 pages, with 200 illustrations on wood and a colored plate. Cloth, $2.75; leather, $3.25. In a few days. A notice of the previous edition is appended. The book opens with a treatise on Chemical Physics, including Heat, Light, Magnetism and Electricity. These subjects are treated clearly and briefly, hut enough is given to enable the stu- dent to comprehend the facts and laws of Chemis- try proper. It is the fashion of late years to omit these topics from works on chemistry but their omission is not to be commended. As was required by the great advance in the science of Chemistry of late years, the chapter on the General Principles: of Chemical Philosophy has been entirely rewrit- ten. The latest views on Equivalents, Quantiva- lence, etc., are clearly and fully set forth. This last edition is a great improvi ment upon its prede- cessors, which is saying not a little of a book that has reached its twelfth edition. — Ohio Medical Re- corder, Oct., 1878. "Wohler's Outlines of Organic Chemistry. Edited by Fittig. Translated by Ira Remsen, M. D., Ph. D. In one 12mo. volume of 550 pages. Cloth, $3. GALLOWAY'S QUALITATIVE ANALYSIS. New i CARPENTER'S PRIZE ESSAY ONTHEUSE AND edition. Abuse OF Aloobolic Liquors in Health and Dis- LEHM ANN'S MANUAL OF CHEMICAL PHYS- bass. With explanations of scientific words. Small IOLOGY. In one octavo volume of 327 pages, 12mo. 178 pages. Cloth, GO cents, with 41 illustrations. Cloth, $2.25. Lea Brothers & Co.'s Publications — Chemistry. FRAXKEAXB,E.,Z>. C. L.,F.R.S.,&JAPP, F.R.,F.E C, Professor of Chemistry in the Xormal School of Science, London. Assist. Prof, of Ch< mistry in the Xormal School of ■• ion. Inorganic Chemistry. In one handsome octavo volume of GOO pages, with 51 woodcuts and 2 lithographic plates. Cloth, $3.75; Leather, $4.75. la a few days. This work on elementary chemistry is based upon principles of classification, nomen- clature and notation which have been proved by nearly twenty years experience in teaching to impart most readily a sound and accurate knowledge of the science. ATTFIELI> 9 JOHX, Ph. D.. Profa ' 'V t'i the Pharmaceutical Society of Great Britain, etc. Chemistry, General, Medical and Pharmaceutical; Including the Chem- istry of the U. S. Pharmacopoeia. A .Manual of the General Principles of the Science, and their Application to Medicine and Pharmacy. A new American, from the tenth English edition, specially revised by the Author. In one handsome royal 12mo. volume of 7-_!> pages, with 87 illustrations. Cloth, §2.50; leather, $3.00. A text-book which passes through ten editions to put himself in the student's place and to appre in sixteen years must have good qualities. This remark is certainly applicable to Attfiehl's Chem- istry, a b wk which IS so well known that it is hardly necessary to do more than note the appear- ance of this new and improved edition, li - however, desirable to point out that feature of the book which, in all probability, his made it so popular. There can be little doubt that it is its thoroughly practical character, the expi being used in its best sense. The author under- stand.-, what the student ought to learn, and is able ciate his state of mind.— 'American Chemical Jour- not, April, 1884. It is a book on which too much praise cannot be I. As a textbook for medical schools it is unsurpassable in the present state of chemical science, and having been prepared with a special view towards medicine and pharmacy, it is alike nsable to all persons engaged in those de- partments of science. It includes the whole chemistry of the last Pharmacopoeia.— Pacific Medt- cal and Sugrical Journal, Jan. lssl. BLOXAM, CHARLES E., Professor of Chemistry in King's College, London. Chemistry, Inorganic and Organic. New American from the fifth Lon- don edition, thoroughly revised and much improved. In one very handsome octavo volume of 727 pages, with 292 illustrations. Cloth, $3.75; leather, $4.75. Comment from us on this standard work is al- most superfluous. It differs widely in scope and aim from that of Att field, and in its way is equally beyond criticism. It adopts the most direct meth- ods in stating the principles, hypotheses ami (acts of the science, Its language is so terse and lucid, and its arrangement of matter so logical in se- : that the student never has occasion to complain that chemistry is a hard study. Much I attention is paid to experimental illustrations of i chemical principles and phenomena, and the >f conducting these experiments. Thebookj maintains the position it has always held as one of | the best manuals of general chemistry in the Eng- lish language. — Detroit Lancet, Feb. 1884. The general plan of this work remains the same as in previous editions, the evident object being to give clear and concise descriptions of all known elements and of their most important compounds, with explanations of the chemical laws and principles involved. We gladly repeat now the ©pinion we expressed about a former edition, that we regard Bloxam's Chemistry as one oi the best treatises on general and applied chemistry. — American Jour, of Pharmacy, Dec. 1883. SIMON, W., Ph. J)., M. Z>., Professor of Chemistry and Toxicology m the College of Physicians and Surgeons, Baltimore, and Professor of Chemistry in the Maryland College, of Pharmacy. Manual of Chemistry. A Guide to Lectures and Laboratory work for Beginners in Chemistry. A Text-book, specially adapted for Students of Pharmacy and Medicine. In one 8vo. vol. of 410 pp., with 16 woodcuts and 7 plates, mostly of actual deposits, with colors illustrating 56 of the most important chemical reactions. Cloth, $3.00; also without plates, cloth, $2.50. Just ready. plates, beautifully executed, illustrating precipi- tates of various reactions, form a novel and valu- This book supplies a want long felt by students of medicine and pharmacy, ana is a concise but thorough treatise on the subject. The long expe- rt the author as a teacher in schools of medicine and pharmacy is conspicuous in tie' perfect adaptation of the work to the special n Is of the student of these branches. The i able feature of the book, and cannot fail to be ap- preciated by both student and teacher as a help over the hard places of the science. — Maryland Medical Journal, Nov. 22, 1884. REJISEX. IRA, M. I)., Ph. T>., Professor of Chemistry in the Johns Hopkins Unirersiti/, Baltimore. Principles of Theoretical Chemistry, with special reference to the Constitu- tion of Chemical Compounds. Second and revised edition. In one handsome royal 12mo. volume oi 240 pages. Cloth, $1.75. Just ready. of chemistry. The high reputation of the author assures its accuracy in all matters of fact, and its judicious conservatism in matters of theory, com- bined with the fulness with which, in a small --, the present attitude of chemical science towards the constitution of compounds is con- sidered, give- it a value much beyond that accorded to the average text-books of the day. — American Journal of Science, March, 1884. The book is a valuable contribution to the chemi- cal literature of instruction. That in so few years a second edition ha- I □ called for indicates that many chemical teacher- have been found ready to endorse its plan and to adopt it- methods. In this edition a considerable proportion of the book has I. ecu rewritten, much new matter hae added and the wholi brought up to date. We earnestly commend this book to every student 10 Lea Brothers & Co.'s Publications — Chemistry. CHARLES, T. CRANSTOUN, M. JD., F. C. S., M. S., Fbrmeriy At Demonst. of Chemistry and Chemical Physics, Queen's College, Belfast. The Elements of Physiological and Pathological Chemistry. A Handbook for Medical Students and Practitioners. Containing a general account of Nutrition, Foods ami Digestion, and the Chemistry of the Tissues, Organs, Secretions and Excretions of the Body in Health and in Disease. Together with the methods for pre- paring or separating their chief constituents, as also for their examination in detail, and an outline syllabus of a practical course of instruction for students. In one handsome octavo volume of 463 pages, with 38 woodcuts and 1 colored plate. Cloth, $3.50. The work is thoroughly trustworthy, and in- formed throughout by a genuine scientific spirit. The author deals with the chemistry of the diges- tive secretions in a systematic manner, which leaves nothing to be desired, and in reality sup- plies a want in English literature. The book ap- pears to us to he at once full and systematic, and to show a just appreciation of the relative import- ance of the various subjects dealt with. — British Medical Journal, November 29, ISS-i. Dr. Charles' manual admirably fulfils its inten- tion of giving his readers on the one hand a sum- mary, comprehensive but remarkably compact, of the mass of facts in the sciences which have be- come indispensable to the physician; and, on the other hand, of a system of practical directions so minute that analyses often considered formidable may be pursued by any intelligent person. — , Dee. 1884. HOFFMANN, F., A.M., Fh.H., & FOWER F.B., Fh.I)., Public Analyst to the State of yew York. Prof, of Anal. Chem. in the Phil. Coll. of Pharmacy. A Manual of Chemical Analysis, as applied to the Examination of Medicinal Chemicals and their Preparations. Being a Guide for the Determination of their Identity and Quality, and for the Detection of Impurities and Adulterations. For the use of Pharmacists, Physicians, Druggists and Manufacturing Chemists, and Pharmaceutical and Medical Students. Third edition, entirely rewritten and much enlarged. In one very handsome octavo volume of 621 pages, with 179 illustrations. Cloth, $4.25. We congratulate the author on the appearance of the third edition of this work, published for the first time in this country also. It is admirable and the information it undertakes to supply is both extensive and trustworthy. The selection of pro- cesses for determining the purity of the substan- ces of which it treats is excellent and the descrip- tion of them singularly explicit. Moreover, it is exceptionally free from typographical errors. We have no hesitation in recommending it to those who are engaged either in the manufacture or the testing of medicinal chemicals. — London Pharma- ceutical Journal and Transactions, 1883. CLOWES, FRANK, L>. Sc, London, Senior Science-Master at the High School, Newcastle-under-Lyme, etc. An Elementary Treatise on Practical Chemistry and Qualitative Inorganic Analysis. Specially adapted for use in the Laboratories of Schools and Colleges and by Beginners. Third American from the fourth and revised English edition. In one very handsome royal 12mo. volume of about 400 pages, with about 50 illustrations. Cloth, $2.50. In a few days. The style is clear, the language terse and vigor- ous. Beginning with a list of apparatus necessary for chemical work, he gradually unfolds the sub- ject from its simpler to its more complex divisions. It is the most readable book of the kind we have yet seen, and is without doubt a systematic, intelligible and fully equipped laboratory guide and text book. — Medical Record, July 18, 1885. We may simply repeat the favorable opinion which we expressed after the examination of the previous edition of this work. It is practical in its aims, and accurate and concise in its statements. — American Journal of Pharmacy, August, 1885. RALFE, CHARLES H., M. D., F. R. C. F., Assistant Physician at the London Hospital. Clinical Chemistry. In one pocket-size 12mo. volume of 314 pages, with 16 illustrations. Limp cloth, red edges, $1.50. This is one of the most instructive little works that we have met with in a long time. The author is a physician and physiologist, as well as a chem- iat, consequently the book is unqualifiedly prac- tical, telling the physician just what he ought to know, of the applications of chemistry in medi- See Students' Series of Manuals, page 3. cine. Dr. Ralfe is thoroughly acquainted with the iatest contributions to his science, and it is quite refreshing to find the subject dealt with so clearly and simply, yet in such evident harmony with the modern scientific methods and spirit. — Medical Record, February 2, 18S4. CLASSEN, ALEXANDER, Professor in the Royal Polytechnic Sellout, Aix-la-Cliapelle. Elementary Quantitative Analysis. Translated, with notes and additions, by Edgar F.Smith. Ph.D., Assistant Professor of Chemistry in the Towne Scientific School, University of Penna. In one 12mo. volume of 324 pages, with 36 illust. Cloth, $2.00. It is probably the best manual of an elementary nature extant insomuch as its methods are the It teaches by examples, commencing with single determinations, followed by separations, and then advancing to the analysis of minerals and such products as are met with in applied chemis- try. It is an indispensable book tor students in chemistry. — Boston Journal of Chemistry, Oct. 1878. GREENE, WILLIAM H., M. H., Demonstrator of Chemistry in the Medical Department of the University of Pennsylvania. A Manual of Medical Chemistry. For the use of Students. Based upon Bow- man's Medical Chemistry. In one 12mo. volume of 310 pages, with 74 illus. Cloth, $1.75. It is a concise manual of three hundred pages, I the recognition of compounds due to pathological giving an excellent summary of the best methods conditions. The detection of poisons is treated of analyzing the liquids and solids of the body, both ; with sufficient fulness for the purpose of thestu- forthe estimation of their normal constituents and i dentor practitioner. — Boston Jt. of Chem., June, '80. Lea Brothers & Co.'s Publications — Pharrn., Mat. Med., Therap. 11 BRUNTON, T. LAUDER, M.D., D.Sc, F.R.S., F.R.C.P., Lecturer on Materia Medica and Therapeutics at St. Bartholomews Hospital, London, etc. A Text-book of Pharmacology, Therapeutics and Materia Medica ; Including the Pharmacy, the Physiological Action and the Therapeutical Usee of Drugs. In one handsome octavo volume of about 1000 pages, with 188 illustrations. Cloth, §5.50 ; leather, $6.50. In press. It is with peculiar pleasure that the early appearance of this long expected work is announced by the publishers. "Written by the foremost authority on its subject in Eng- land, it forms a compendious treatise on materia medica, pharmacology, pharmacy, and the practical use of medicines in the treatment of disease. Space has been devoted to the fundamental sciences of chemistry, physiology and pathology, wherever it seemed necessary to elucidate the proper subject-matter of the book. A general index, an index of diseases and remedies, and an index of bibliography close a volume which will undoubtedly be of the highest value to the student, practitioner and pharmacist. It is a scientific treatise worthy to be ranked with the highest productions in physiology, either in our own or any other language. Everything is practical, the dry, hard facts of physiology bein^ pressed into service and applied to the treatment of the commonest complaints. The information is so systematically arranged that it is available for immediate use. The index is so carefully compiled that a reference to any special point is at once obtainable. Dr. Brunton is never satisfied with vague generalities, but gives clear and pre- cise directions for prescribing the various drugs and preparations. We congratulate students on being at last placed in possession of a scientific treatise of enormous practical importance.— The Lancet, June 27, 1885. PARRISH, EDWARD, Late Professor of the Tlieory and Practice of Pharmacy in the Philadelphia College of Pharmacy. A Treatise on Pharmacy : designed as a Text-book for the Student, and as a Guide for the Physician and Pharmaceutist. With many Formulae and Prescriptions. Fifth edition, thoroughly revised, by Thomas S. "Wiegand, Ph. G. In one handsome octavo volume of 1093 pages, with 256 illustrations. Cloth, $5 ; leather, $6. No thoroughgoing pharmacist will fail to possess I Each page bears evidence of the care bestowed himself of so useful a guide to practice, and no upon it, and conveys valuable information from physician who properly estimates the value of an the rich store of the editor's experience. In fact, accurate knowledge of the remedial agents em- all that relates to practical pharmacy— apparatus, ployed by him in daily practice, so far as their processes and dispensing— has been arranged and miscibility, compatibility and mosteffectivemeth- described with clearness in its various aspects, so ods of combination are concerned, can afford to as to afford aid and advice alike to the student and leave this work out of the list of their works of to the practical pharmacist. The work is judi- reference. The country practitioner, who must ciously illustrated with good woodcuts — American always be in a measure his own pharmacist, will Journal of Pharmacy, January, 1884. find it indispensable. — Louisville Medical yews, There is nothing to equal Parrish's Pharmacy March 29, 1884. in this or any other language.— London Pharma- This well-known work presents itself now based I ceutical Journal. upon the recently revised new Pharmacopoeia. | HERMJlNX, Dr. L., Professor ( i in Hie University of Zurich. Experimental Pharmacology. A Handbook of Methods for Determining the Physiological Actions of Drugs. Translated, with the Author's permission, and with extensive additions, by Eobert Meade Smith, M. D., Demonstrator of Physiology in the University of Pennsylvania. In one handsome 12mo. volume of 199 pages, with 32 illustrations. Cloth, §1.50. MAISCH, JOHX M.7xnne pocket-size 12ino. volume of 555 pages. Limp cloth, $1.50. Just ready. See Student.--' Series of Manuals, page 3. GRIFFITH, ROBERT EGLESFIELD, M. D. A Universal Formulary, containing the Methods of Preparing and Adminis- tering Officinal and other Medicines. The whole adapted to Physicians and Pharmaceut- ists. Third edition, thoroughly revised, with numerous additions, by John M. Maisch, Pliar. D., Professor of Materia Medica and Botany in the Philadelphia College of Pharmacy. In one octavo volume of 775 pages, with 3S illustrations. Cloth, $4.50; leather, $5.50. 12 Lea Brothers & Co.'s Publications — Mat. Med., Therap. STILLE, A., M. J)., LL. D., & MAISCH, J. M., Thar. Z)., Professor Emeritus of the Theory and Prae- Prof, of Mat. Med. and Botany in Phila. tice of Medicine and of Clinical Medicine in tl- \ of Pennsylvania. ran Pharti ion. The National Dispensatory: Containing the Natural History, Chemistry, l'har- macv. Actions and Uses of Medicines, including those recognized in the Pharmacopoeias of the United States, Great Britain and Germany, with numerous references to the French Codex. Third edition, thoroughly revised and greatly enlarged. In one magnificent imperial octavo volume of 17G7 pages, with oil tine engravings. Cloth, $7.25; leather, $8.00; half Russia, open back, $9.00. With Denison's "Ready Reference Index" $1.00 in addition to price in any of above styles of binding. Just ready. In the present revision the authors have labored incessantly with the view of making the third edition of The National, Dispensatory an even more complete represen- tative of the pharmaceutical and therapeutic science of 1884 than its first edition was of that of 1879. For this, ample material has been afforded not only by the new United States Pharmacopoeia, but by those of Germany and France, which have recently appeared and have been incorporated* in the Dispensatory, together with a large number of new non- officinal remedies. It is thus rendered the representative of the most advanced state of American, English, French and German pharmacology and therapeutics. The vast amount of new and important material thus introduced may be gathered from the fact that the additions to this edition amount in themselves to the matter of an ordinary full-sized octavo volume, rendering the work larger by twenty-five per cent, than the last edition. The Therapeutic Index (a feature peculiar to this work), so suggestive and convenient to the practitioner, contains 1600 more references than the last edition — the General Index 3700 more, making the total number of references 22,390, while the list of illustrations has been increased by 80. Every effort has been made to prevent undue enlargement of the volume by having in it nothing that could be regarded as superfluous, yet care has been taken that nothing should be omitted which a pharmacist or physician could expect to find in it. The appearance of the work has been delayed by nearly a year in consequence of the determination of the authors that it should attain as near an approach to absolute ac- curacy as is humanly possible. With this view an elaborate and laborious series of examinations and tests have been made to verify or correct the statements of the Pharma- copoeia, and very numerous corrections have been found necessary. It has thus been ren- dered indispensable to all who consult the Pharmacopoeia. The work is therefore presented in the full expectation that it will maintain the position universally accorded to it as the standard authority in all matters pertaining to its subject, as registering the furthest advance of the science of the day, and as embody- ing in a shape for convenient reference the recorded results of human experience in the laboratory, in the dispensing room, and at the bed-side. Comprehensive in scope, vast in design and | up to date. The work has been very well done, a Bplendid in execution. The National Dispensatory large number of extra-pharmacopceia! remedies may bejustl as the most important work having been added to those mentioned in previous of its kind extant. — Louisville Medical News, Dec. editions. — London Lancet, Nov. i':i, ls>4. 6, 18S I. Its completeness as to subjects, the comprehen- AVe have much pleasure in recording the appear- siveness of its descriptive language, the thorough- ance of a third edition of this exc< Hi nt work of ness of the treatment of the topics, its brevity not reference. It is an admirable abstract ■■fall that sacrificing the desirable features of information relates to chemistry, pharmacy, materia medica, for which such a work is needed, make this vol- pharmacology and "therapeutics. It may be re- time a marvel of excellence. — Pharmaceutical .Re- garded as embodying the Pharmacopoeias of the cord, Aug. 15, 1884 civilized nations of the world, all being brought I FARQV1IARSOX, ROBERT, M. D., Lecturer on Materia Medica at St. Mary's Hospital Medical School. A Guide to Therapeutics and Materia Medica. Third American edition, specially revised by the Author. Enlarged and adapted to the U. S. Pharmacopoeia by Frakk Woodbtjky, M. D. In one handsome 12mo. volume of 524 pages. Cloth, $2.2o. Dr. Farquharson's Therapeutics is constructed umned pages— one side containing the recognized upon a plan which brings before the reader all tin physiological action of the medicine, andthe other essential points with reference to the properties of the disease in which observers (who are nearly al- drugs. It impresses these upon him in such a way ways mentioned) have obtained from it good re- as bo enable him to take a clear view of the actions suits— make a very good arrangement The early of medicines and the disordered conditions in chapter containing rules for prescribing is excel- which they must prove useful. The double-col- lent.— ' and Surg. Journal, Dec. 1882. STILLE, ALFRED, 31. J)., LL. 1)., Professor of Them y ., F. R. C. P. E., Demonstrator of Pathology in the University of Edinburgh. Practical Pathology. A Manual for Students and Practitioners, tiful octavo volume of 497 pages, with 136 exquisitely colored illustrations. It forms a real guide for the student and practi- tioner who is thoroughly In earnest in his en- deavor to see for himself anil do for himself. To the laboratory student it will be a helpful com- panion, and all those who may wish to familiarize themselves with modern methods of examining morbid tissues are strongly urged to | themselves with this manual. The numerous drawings arc not fancied pictures, or merely schematic diagrams, but they represent faithfully the actual images seen under the microscope. In one beau- Cloth, $6.00. The author merits all praise for having produced OTk.— Medical Record, May 31, 1884. It l- manifestly the product of one who has him- self travel led over the whole field and who is skilled rely in the art of histology, but in the vation and interpretation of morbid changes. The - -me to command a wide circulation. It should do much to encourage the pursuit of path- jince such advantages in hi-tological study have never before been offered. — The Lancet, Jan. 5, 1884. SCHAFER, EDWARD A., F. R. S., u University College, London. The Essentials of Histology. In one octavo volume of 246 pages, with 281 illustrations. Cloth, $2.25. Shortly. CORJSTIL, V., and RAXYIER, L., Prof, in the Far'ilf'i of M Prof, in the College of France. A Manual Of Pathological Histology. Translated, with notes and additions, by E. (). Shakespeare, M. D., Pathologist and Ophthalmic Sunreon to Philadelphia Hospital, and by J. Henry C. Semes, M. I'., Demonstrator of Pathological Histology in the university of Pennsylvania, la one very handsome octavo volume of 800 [ ages, with 360 illustrations. Cloth, $5.50 ; leather, $6.50; half Russia, raised bands, $7. KLEIX, E„ M. D., F. R. S., al Anat. and Phys. in the Med. School of St. Bartholomew's Hasp., London. Elements of Histology. In one pocket-size 12mo. volume of 360 pages, with 181 tllns. Limp cloth, red edges, $1.50. of Manuals, page 3. Ugh an elein , jt is by no < superficial or incomplete, for the author | guage nearly all the fundamental facts regarding the microscopic structure of I The illustrations are numerous and excellent. We commend L>r. Klein's 1 : heartily to the student.— Medical Pecord, Dec. 1, 1883. PEPPER, A. J., M. B., M. S., F. R. C. S., Hospital, London. Surgical Pathology. In one pocket-size 12mo. volume of 511 pages, with 81 illustrations. Limp cloth, re It is not pretentious, but it will - ustrated. The student will find in it nothing in gly well as a book of reference. It embodies a that is unnecessary. The list -vers gr>-at deal of matter, extending over the whole the whole range of surgery. The I k supplies a field of surgical pathology. Its form is practical, very manifest wan' • with suc- its language is clear, and the information -• : tress. — New York Medical Journal, May 31, 1684 forth is well-arranged, well-indexed and well- BCHAFER'S PRACTICAL HISTOLOGY. In one I OGY. Translated by Joseph Lanrr, M. D. In one handsome royal 12mo. volun th I volume, very large imperial quarto, with 33» 40 illl in and colored and dr«- GLUGE'S ATLAS OF PATHOLOGICAL HISTOL- | cru'tivc letter-press. Cloth, $4.00 14 Lea Brothers & Co.'s Publications — Practice of Med. FLINT, AUSTIN, M. !>., Prof, of the Principles and Practice of Med. and of Clin. Med. in BeUevue Hospital Medical College, N. Y. A Treatise on the Principles and Practice of Medicine. Designed for the use of Students and Practitioners of Medicine. With an Appendix on the Researches of Koch, and their bearing on the Etiology, Pathology, Diagnosis and Treatment of Phthisis. Fifth edition, revised and largely rewritten In one large and closely -printed octavo volume of 1160 pages. Cloth, $5.50; leather, $6.50; half Russia, $7. Koch's discovery of the bacillus of tubercle gives promise of being the greatest boon ever conferred by science on humanity, surpassing even vaccination in its benefits to mankind. In the appendix to his work, Professor Flint deals with the subject from a practical standpoint, discussing its bearings on the etiology, pathology, diagnosis, prog- nosis and treatment of pulmonary phthisis. Thus enlarged and completed, this standard work will be more than ever a necessity to the physician who duly appreciates the re- sponsibility of his calling. A well-known writer and lecturer on medicine recently expressed an opinion, in the highest de- gree complimentary of the admirable treatise of Dr. Flint, and in eulogizing it, he described it ac- curately as " readable and reliable." No text-book is more calculated to enchain the interest of the student, and none better classifies the multitudi- nous subjects included in it. It has already so far won its way in England, that no inconsiderable number of men use it alone in the study of pure medicine; and we can say of it that it is in every way adapted to serve, not only as a complete guide, but also as an ample instructor in the science and practice of medicine. The style of Dr. Flint is always polished and engaging. The work abounds in perspicuous explanation, and is a most valuable text-book of medicine. — London Medical News. This work is so widely known and accepted as the best American textbook of the practice of medicine that it would seern hardly worth while to give this, the fifth edition, anything more than a passing notice. But even the most cursory exami- nation shows that it is, practically, much more than a revised edition ; it is, in fact, father a new work throughout. This treatise will undoubtedly continue to hold the first place in the estimation of American physicians and students. No one of our medical writers approaches Professor Flint in clearness of diction, breadth of view, and, what we regard of transcendent importance, rational esti- mate of the value of remedial agents. It is thor- oughly practical, therefore pre-eminently the book for American readers. — St. Louis Clin. Rec, Mar. '81. HARTSHORNE, HENRY, 31. !>., LL. !>., Lately Professor of Hygiene in the University of Pennsylvania. Essentials of the Principles and Practice of Medicine. A Handbook for Students and Practitioners. Fifth edition, thoroughly revised and rewritten. In one royal 12mo. volume of 669 pages, with 144 illustrations. Cloth, $2.75 ; half bound, $3.00. Within the compass of GOO pages it treats of the history of medicine, general pathology, general symptomatology, and physical diagnosis (including laryngoscope, ophthalmoscope, etc.), general ther- apeutics, nosology, and special pathology and prac- tice. There is a wonderful amount of information contained in this work, and it is one of the best of its kind that we have seen. — Glasgow Medical Journal, Nov. 1S82. An indispensable book. No work ever exhibited a better average of actual practical treatment than this one; and probably not one writer in our day had a better opportunity than Dr. Hartshorne for condensing all the views of eminent practitioners into a 12mo. The numerous illustrations will be very useful to students especially. These essen- tials, as the name suggests, are not intended to supersede the text-books of Flint and Bartholow, but they are the most valuable in affording the means to see at a glance the whole literature of any disease, and the most valuable treatment. — Chicago Medical Journal and Examiner, April, 1882. BRISTOWE, JOHN SYER, M. 2>., F. R. C. P., Physician and Joint Lecturer on Medicine at St. Thomas' 1 Hospital. A Treatise on the Practice of Medicine. Second American edition, revised by the Author. Edited, with additions, by James H. Hutchinson, M.D., physician to the Pennsylvania Hospital. In one handsome octavo volume of 1085 pages, with illustrations. Cloth, $5.00 ; leather, $6.00 ; very handsome half Russia, raised bands, $6.50. The reader will find every conceivable subject connected with the practice of medicine ably pre- sented, in a style at once clear, interesting and concise. The additions made by Dr. Hutchinson are appropriate and practical, and greatly add to its usefulness to American readers. — Buffalo Med- ical and Surgical Journal, March, 1880. WATSON, SIR THOMAS, M. !>., Late Physician in Ordinary to the Queen. Lectures on the Principles and Practice of Physic. A new American from the fifth English edition. Edited, with additions, and 190 illustrati ms, by Henry Hartshorne, A. Si., M. D., late Professor of Hygiene in the University of Pennsylvania. In two large octavo volumes of 1840 pages. Cloth, $9.00 ; leather, $11.00. LECTURES ON THE STUDY OF FEVER. By A. Hudson, M. D., M. R. I. A. In one octavo volume of 308 pages. Cloth, $2.50. STOKES' LECTURES ON FEVER. Edited by John William Moore, M. D., F. K. Q. C. P. In one octavo volume of 280 pages. Cloth, $2.00. A TREATISE ON FEVER. By Robert D. Lyons, K. C. C. In one 8vo. vol. of 354 pp. Cloth, $2.25. LA ROCHE ON YELLOW FEVER, considered in its Historical, Pathological, Etiological and Therapeutical Relations. In two large and hand- some octavo volumes of 1468 pp. Cloth, $7.00. A CENTURY OF AMERICAN MEDICINE, 1776—1876. By Drs. E. H. Clarke, H. J. Bigelow, S. D. Gross, T. G. Thomas, and J. S. Billings. In one 12mo. volume of 370 pages. Cloth, $2.25. Lea Brothers & Co.'s Publications — Systems of Med. 15 For Sale by Subscription Only. A System of Practical Medicine. BY AMERICAN AUTHORS. Edited by WILLIAM PEPPER, M. D., LL. D., PROVOST AND PROFESSOR OP THE THEORY AND PRACTICE OP MEDICINE AND OF CLINICAL MEDICINE IN THE UNIVERSITY OF PENNSYLVANIA, Assisted by Louis Starr, M. D., Clinical Professor of the Diseases of Children in the Hospital of the University of Pennsylvania. In five imperial octavo volumes, containing about 1100 pages each, with illustrations. Price per volume, cloth, $5; leather, $6; half Russia, raised bands and open back, $7. Volume I. (General Pathology, Sanitary Science and General Diseases) contains 1094 pages, with 24 illustrations and is just ready. Volume II. (General Diseases [con- tinued] and Diseases of the Digestive System) contains 1312 pages, with 27 illustrations, and is just ready. Volume III. (Diseases of , the Respiratory, Circulatory and Haematopoietic Systems) containing about 10-50 pages, will be ready October 1st, and the subsequent volumes at intei~vals of four months thereafter. The publishers feel pardonable pride in announcing this magnificent work. For three years it has been in active preparation, and it is now in a sufficient state of forward- ness to justify them in calling the attention of the profession to it as the work in which for the first time American medicine is thoroughly represented by its worthiest teachers, and presented in the full development of the practical utility which is its preeminent characteristic. The most able men — from the East and the West, from the North and the South, from all the prominent centres of education, and from all the hospitals which afford special opportunities of study and practice — have united in generous rivalry to bring together this vast aggregate of specialized experience. The distinguished editor has so apportioned the work that each author has had assigned to him the subject which he is peculiarly fitted to discuss, and in which his views will be accepted as the latest expression of scientific and practical knowledge. The practitioner will»therefore find these volumes a complete, authoritative and unfailing work of reference, to which he may at all times turn with full certainty of finding what he needs in its most recent aspect, whether he seeks information on the general principles of medi- cine, or minute guidance in the treatment of* special disease. So wide is the scope of the work that, with the exception of midwifery and matters strictly surgical, it embraces the whole domain of medicine, including the departments for which the physician is accustomed to rely on special treatises, such as diseases of women and children, of the genito-urinary organs, of the skin, of the nerves, hygiene and sanitary science, and medical ophthalmology and otology. Moreover, authors have inserted the formulas which they have found most efficient in the treatment of the various affections. It may thus be truly regarded as a Complete Library of Practical Medicine, and the general practitioner possessing it may feel secure that he will require little else in the daily round of professional duties. In spite of every effort to condense the vast amount of practical information fur- nished, it has been impossible to present it in less than 5 large octavo volumes, containing aboul 5500 beautifully printed pages, and embodying the matter of about 15 ordinary octavos. Illustrations arc introduced wherever they serve to elucidate the text. As material for the work is substantially complete in the hands of the editor, the pro- fession may confidently await the appearance of the remaining volumes upon the dates above specified. A detailed prospectus of the work will be sent to any address on appli- cation to the publishers. It is a large undertaking, but quite justifiable in this country as authorities on the particular topics the ease of a progressive nation like the United oo which they deal, whilst the others show by the States. At any rate, if we may judge of future way they have handled their subjects that they volumes from the first it will be justified by the , are fully equal to the task they had undertaken, result. We have nothing but praise to bestow • * * A work which we cannot doubt will make upon the work. The articles are the work of a lasting reputation for itself.— London Medical writers, many of whom are already recognized in j Times and Gazette, May 9, 1885. REYNOLDS, J. BUS8JEZZ, M. I)., Professor of the Principled and Practice of Medicine in University College, London. A System Of Medicine. With notes and additions by Henry IIartshorne, A. M., M. D., late Professor cf Hygiene in the University of Pennsylvania. In three large and handsome octavo volumes, containing 3056 double-columned pages, with 317 illustra- tions. Price per volume, cloth, $5.00 ; sheep, $6.00 ; very handsome half Russia, raised bands, $6.50. Per set, cloth, $15; leather, $18; half Russia, $19.50. Sold only by subscript!' ' 16 Lea Brothers & Co.'s Publications — Clinical Med., etc. STILL E, ALFRED, 31. T>., LL. I)., I'r i ssor Emeritus of the Theory ayid Practice of Med. and of Clinical Med. in the Univ. of Penna. Cholera: Its Origin, History, Causation, Symptoms, Lesions, Prevention and Treat- ment. In one handsome 12mo. volume of 163 pages, with a chart. Cloth, $1.25. Just ready. The threatened importation of cholera into the country renders peculiarly timely this work of an authority upon the subject so eminent as Professor Stille. The history of previous epidemics, their modes of propagation, the vast recent additions to our knowledge of the causation, prevention and treatment of the disease, all have been handled so skilfully as to present with brevity the information which every practitioner should possess in advance of a visitation. This timely little work is full of the learning and good judgment which marks all that cornea from the pen of its distinguished author. What he has to say on treatment is characterized by his usual caution and his well-known preference for a rational system. Altogether, the monograph is one that will have an excellent influence on the professional minct.— Medical and Surgical Reporter, August 1, 1885. q. FLINT, AUSTIN, 31. TJ. Clinical Medicine. A Systematic Treatise on the Diagnosis and Treatment of Diseases. Designed for Students and Practitioners of Medicine. In one large and hand- some octavo volume of 799 pages. Cloth, $4.50; leather, $5.50 ; half Russia, $6.00. It is here that the skill and learning of the great clinician are displayed. He has given us a store- house of medical knowledge, exeellentfor the stu- dent, convenient for the practitioner, the result of a long life of the most faithful clinical work, col- lected by an energv as vigilant and systematic as untiring, and weigbed by a judgment no less clear than his observation is close. — Archives of Medicine, Dec. 1879. To give an adequate and useful conspectus of the extensive field of modern clinical medicine is a task of no ordinary difficulty; but to accomplish this con- sistently with brevity and clearness, the different subjects and their several parts receiving the attention which, relatively to their importance, medical opinion claims for them, is still more diffi- cult. This task, we feel bound to say, has been executed with more than partial success by Dr. Flint, whose name is already familiar to students of advanced medicine in this country as (hat of the author of two works of great merit on special subjects, and of numerous papers exhibiting much originality and extensive research. — 7 he Dublin Journal, Dec. 1879. By the Same Author. Essays on Conservative Medicine and Kindred Topics. In one very hand- some royal 12ino. volume of 210 pages. Cloth, $1.38. BROADBENT, W . JBT., M. !>., F. R. C. P., Physician to and Lecturer on Medicine at St. Mary's Hospital. The Pulse. In one 12rno. volume. See Series of Clinical il/cmua/s,. page 3. SCSREIBER, DR. JOSEPH. A Manual of Treatment by Massage and Methodical Muscle Ex- ercise. Translated by Walter Mendelson, M. D., of New York. In one handsome octavo volume of about 300 pages, with about 125 fine engravings. Preparing. FINLAYSON, J AWES^M7lJ7, Editor, Physician and Lecturer on Clinical Medicine in the Glasgow Western Infirmary, etc. Clinical Diagnosis. A Handbook for Students and Practitioners of Medicine. With Chapters by Prof. Gairdner on the Physiognomy of Disease ; Prof. Stephens^ on Diseases of the Female Organs; Dr. Robertson on Insanity; Dr. Gemmell on Physical Diagnosis; Dr. Coats on Laryngoscopy and Post-Mortem Examinations, and by the Editor on Case-taking, Family History and Symptoms of Disorder in the Various Systems. In one handsome 12rno. volume of 546 pages, with 85 illustrations. Cloth, $2.63. FENWICK, SA3TUEL, M. D., Assistant Physician to the London Hospital. The Student's Guide to Medical Diagnosis. From the third revised and enlarged English edition. In one very handsome royal 12mo. volume of 328 pages, with 87 illustrations on wood. Cloth, $2.25. TANNER, THOMAS HAWKES, 31. D. A Manual of Clinical Medicine and Physical Diagnosis. Third American from the second London edition. Revised and enlarged by Tilbury Fox, M. D. In one small 12mo. volume of 362 pages, with illustrations. Cloth, $1.50. FOTHERGILL, J. 31., M. D., Edin., M. R. C. P., Lond., Physician to the City of London Hospital for Diseases of the Chest. The Practitioner's Handbook of Treatment ; Or, The Principles of Thera- peutics. New edition. In one octavo volume. Preparing. STURGES' INTRODUCTION TO THE STUDY OF CLINICAL MEDICINE. Being a Guide to the Investigation of Disease. In one handsome 12mo. volume of 127 pages. Cloth, $1.25. DAVIS' CLINICAL LECTURES ON VARIOUS IMPORTANT DISEASES. By N. S. Davi& M. D. Edited by Frank H. Davis, M. D. Second edition. 12mo. 287 pages. Cloth, $1.75. Lea Brothers & Co.'s Publications — Hygiene, Elect r., Pract. 17 RICHAR&SOX, B. W.. M.A., M.D., LL. L>., F.R.S., F.S.A. Fellow of the Roi/al Coll eye of V udon. Preventive Medicine. In one octavo volume of 729 pages. Cloth, $4; leather, $ 5 ; very handsome half Russia, raided bam Dr. has succeeded in producing a the question of disease is comprehensive, master!/ work which is elevated in conception, comprehen- and fully abreast with the :nowt sive i' ntific in character, systematic in ed arrangement, ami which is written in a clear, con- advised are ac i —The manner, Ii (acuity or extracting the pith of what is kn > ok that will surely find a place on the the subject, and of presenting it in a most simple, table of every progressive p ! i the Intelligent and practical form. Thi uchto no similar work written for the general public prevent as to cure dig thatcontains such acomplete, reliable and instruc- — Bosto 1884. fcive collection of data upon the diseases common Thetri ;, valu- to the race, their origins, causes, and ,: e nrn asures i able hygienic information.— .1/ -rgioal for their prevention. The descriptions of diseases Reporter, Feb. 23, 1884. are clear, chaste and scholarly ; the discussion of | BARTHOLOW, ROBERTS, A. M. 9 M. D., LL. J)., Prof, of Materia Mcdica and General Therapeutics in the Jtfft Medical Electricity. A Practical Treatise on the Applications of Electricity to Medicine and Surgery. Second edition, in one very handsome octavo volume i pages, with 109 illustrations. Cloth, $2.50. The second edition of this work following so A most excellent work, addressed by a practl- soon upon the first would in itself i a tioner to his :■ itioners, and therefore sufficient announcement; nevertheless, the text thoroughly practical. The work now Kef. re us has been so considerably revised a exceptional merit of cl< ig out and so much enlarged by the addition of new mat- where the benefits to be derived from electricity ter, that we cannot ignise a vast improve- must come. It contains ail and everything that ment upon the former work. The author has pre- the practitioner needs in order to understand in- pared his work for students and practitioner-— for , telligently the nature and laws of the agent he is those who have neve' acquainted th< . use of, and for i: the subject, or, having done so, find that after a | practice. In a condensed, prac t pre- time their knowledge needs refreshing. We thin the physician all that lie would wish to he has accomplished t .' i i — object. The book Is not , rememberafterperusinga whole library or. medical too voluminous, but is thoroughly practical, Bim- 1 electricity, including the results -t in- pie, complete and comprehensible. It is, more- vestieations. It is the book for tic practitioner, over, replete with numerous illustrations of instru- : and the necessity for . | tion provi ments, appliances, etc. — Medical Record, .November , it has been appreciated by the profession. — Ptiysi- | cian and Sun/con, Dec. i THE YEAR-BOOK OF TREATMENT. A Comprehensive and Critical Review for Practitioners of Medi- cine. In one 12mo. volume of 320 pages, bound in limp cloth, with red edges, : This work j -t > ■-* 1 1 1 ~ to the practitioner not only a complete classified account of all the more important advances made in the treatment of Disease during the year ending Sept. 30, L884. but also a critical estimate of the same by a competent authority. Each department of practice has been fully and concisely treated, and into the COnsideratl each subject enter such allusions to recent pathological and clinical work as bear directly upon treatment. As the medical literature of all countries has been placed under contri- bution, the references given throughout the work, together with the separate index subjects and authors, will serve as a guide for those who desire to investigate any thera- d topic at greater Length. In a few moments the busy practitioner oan re- I can Journal of ti fresh his mind as to the principal advances in' It is a complete account of tin. more important treatment for a year past. This kind of work is advances mad: In the treatment Ex- feculiarly useful at the present time, when current treme pains have i>. i ly in Iterature i- teeming with innumerable so-called thi advances, of which the practitioner ha- not time writer, and the detail- ol I to determine the value. B«-re he has, collected the principle points about the b from many sources, a rlmmi of the theories ami yet concise langnagi rhich are new, either entirely or in part, the I formed his duty, and we can say with truth thai decision as to their novelty being made by those it is a volume well worth buying for frequen^um. who by «ide reading ana long experience are —Virginia Medico fully competent to render such a verdict.— HABERSHON, S. (>.. M. />., i Practice of Mrd. at Guii'< Ifi'spita', IvOndon. On the Diseases of the Abdomen; Comprising those of tl S h, and other | «arts of the Alimentary (anal, CEsoph m, Intestines and Peritoneum. > American from third enlarged and revised English edition. In one b ctavo volume of 554 pages, with illustrations, (loth, | PA We TREATISE ON THE FUN< HON OF DI- GESTION; its in-orders and their Treatment From the second London edition. In one volume of . ('II A M BERS' MANUAL OF Dl F.T \ M > H Hi ; I M EN IN HEALTH AND BICKNESa In on< some octavo volume ■ : 75. BARLOWS MANUAL OF THE PRACTK MEDICINE. With additions by D. F. I M. D. 1 vol. 8vo , |p TODD'S CLINICAL LECTURES ON CERTAIN ACUTE DISEASES, In one octavo volume of 390 pa _ HOLLAND'S MEDICAL NOTES AND REFLEC- TS INS, 1 vol. -Hi, pp.4 , ;;j.5o. 18 Lea Brothers & Co.'s Publications — Throat, Lungs, Heart. COHEX, J. SOUS, M. JO., Lecturer on Laryngoscopy and Diseases of the Throat and Chest in the Jefferson Medical College. Diseases of the Throat and Nasal Passages. A Guide to the Diagnosis and Treatment of Affections of the Pharynx, (Esophagus, Trachea, Larynx and Nares. Third edition, thoroughly revised and rewritten, with a large number of new illustrations, in one very handsome octavo volume. Preparing. SEILEB, CABL, M. D., Lecturer on Laryngoscopy in the University of Pennsylvania. A Handbook of Diagnosis and Treatment of Diseases of the Throat, Nose and Naso-Pharynx. Second edition. In one handsome royal 12mo. volume of 294 pages, with 77 illustrations. Cloth, $1.75. It is one of the best of the practical text-books | the essentials of diagnosis and treatment in dis- on this subject with which we are acquainted. The : eases of the throat and nose. The art of laryngos- present edition has been increased in size, but its j copy, the anatomy of the throat and nose and the eminently practical character has been main- , pathology of the mucous membrane are discussed tained. Many new illustrations have also been with conciseness and ability. The work is pro- intro.! . e-reeord sheet has been added, fusely illustrated, excels in many essential feat- and there are a valuable bibliography and a good ares, and deserves a place in the office of the index of the whole. For any one who wishes to practitioner who would inform himself as to the make himself familiar with the practical manage- nature, diagnosis and treatment of a class of dis- ment of eases of throat and nose disease, the book i eases almost inseparable from general medical will be found of great value. — Xew York Medical ' practice. With advanced students the book must Journal, June 9, 1883. be very popular on account of its condensed style. The work before us is a concise handbook upon | — Louisville Medical News, June 26, 1883. BROWNIE, LENNOX, F. B. C. S., Edin., Senior Surgeon to the Central London Throat and Ear Hospital, etc. The Throat and its Diseases. Second American from the second English edi- tion, thoroughly revised. With 100 typical illustrations in colors and 50 wood engravings, designed and executed by the Author. In one very handsome imperial octavo volume of about 350 pages. Preparing. FLINT, AUSTIN, 31. D., Professor of the Principles and Practice of Medicine in Bellevue Hospital Medical College, N. T. A Manual of Auscultation and Percussion ; Of the Physical Diagnosis of Diseases of the Lungs and Heart, and of Thoracic Aneurism. Third edition. In one hand- some royal 12mo. volume of 210 pages. Cloth, $1.63. It is safe to say that there is not in the English [ the results of his careful study and ample ex- language, or any other, the equal amount of clear, ! perience in such wise that the young will find it the exact ana comprehensible information touching | best source of instruction, and the old the most the physical exploration of the chest, in an equal pleasant means of reviving and complementing number of words. Professor Flint's language, is their knowledge. — American Practitioner, June, precise and simple, conveying without dubiety [ 1S83. BY THE SAME AUTHOR. Physical Exploration of the Lungs by Means of Auscultation and Percussion. Three lectures delivered before the Philadelphia County Medical Society, 1882-S3. In one handsome small 12mo. volume of 83 pages. Cloth, $1.00. A Practical Treatise on the Physical Exploration of the Chest and the Diagnosis of Diseases Affecting the Respiratory Organs. Second and revised edition. In one handsome octavo volume of 591 pages. Cloth, §4.50. Phthisis: Its Morbid Anatomy, Etiology, Symptomatic Events and Complications, Fatality and Prognosis, Treatment and Physical Diag- nosis ; In a series of Clinical Studies. In one handsome octavo volume of 442 cages. Cloth, $3.50. A Practical Treatise on the Diagnosis, Pathology and Treatment of Diseases of the Heart. Second revised and enlarged edition. In one octavo volume of 55D pages, with a plate. Cloth, $4. GBOSS, S. I)., M.I)., LL.D., D.C.L. Oxon.. II.D. Cantab. A Practical Treatise on Foreign Bodies in the Air-passages. In one octavo volume of 452 pages, with 59 illustrations. Cloth, $2.75. FULLER ON DISEASES OF THE LUNGS AND SMITH ON CONSUMPTION; its Early and Reme- AIi: -. Their Pathology, Physical Di- ' diable Stages. 1 vol. 8vo., pp. 253. Cloth, $2.25. agnosis, Symptoms and Treatment. From the LA ROCHE ON PNEUMONIA. 1 vol. 8vo. of 400 ad and revised English edition. In one pa^es Cloth S3 00 octavo volume of 475 pages. Cloth, £3.50. wiLUAMS (^PULMONARY CONSUMPTION; &LADEOIS DIPHTHERIA; its Nature and Treat- its Nature, Varieties and Treatment. With an ment, with an account of the History of its Pre- analysis of one thousand cases to exemplify its valence in various Countries. Second and revised duration. In one 8vo. vol. of 303 pp. Cloth, $2.50. edition. In one 12mo. vol., pp. 158. Cloth, 81.25. J0 NES' CLINICAL OBSERVATIONS ON FUNC- WALSHE ON THE DISEASES OF THE HEART TIONAL NERVOUS DISORDERS. Second Am- AND GREAT VESSELS. Third American edi- erican edition. In one handsome octavo volume tion. In 1 vol. 8vo., 416 pp. Cloth, 83.00. of 340 pages. Cloth, 83.25. Lea Brothers & Co.'s Publications — Nerv. and Ment. Dis., etc. 19 MITCHELL, S. WEIR, 31. I)., Physician to Orthopaedic Hospital and the Infirmary for Diseases of the Nervous System, Phila., etc. Lectures on Diseases of the Nervous System; Especially in Women. Second edition. In one 12m of 288 pages. Cloth, $1.75. Just ready. We feel sure thai the new edition of Dr. Mitch ell'8 admirable lectures will be received on this side of the Atlantic with more than ordinary at- tention. His subject, the nervous disorders of women, is one that interests every practitioner, and his views on treatment are gradually receiving general acceptance. — London 1& tes and July 4, 1885. BOSS, JAMES, 31. D., F.R. C.P., LL. L>., Senior Assistant Physician to the Manchester Royal Infirmary. A Text-Book on Diseases of the Nervous System. In one handsome octavo volume of 600 pages, fully illustrated. Shortly. HAMILTON, ALLAN McLAJSE, M. H., Attending Physician at the Hospital for Epileptics and Paralytics, BlackweWs Island, N. Y. Nervous Diseases ; Their Description and Treatment. Second edition, thoroughly revised and rewritten. In one octavo volume of 598 pages, with 72 illustrations. Cloth, $4. When thefirstedition of this good book appeared characterized this book as the best of its kind in we gave it our emphatic endorsement, and the any language, which is a handsome endorsement E resent edition enhances our appreciation of the from an exalted source. The improvements in the ook and its author as a safe guide to students of new edition, and the additions to it, will justify its clinical neurology. One of the best and most purchase even by those who possess the old. — critical of English neurological journals, Brain, has i Alienist and Neurologist, April, 1882. TUKJE, DANIEL HACK, M. D., Joint Authm of The Manual of Psychological Medicine, etc. Illustrations of the Influence of the Mind upon the Body in Health and Disease. Designed to elucidate the Action of the Imagination. New edition. Thoroughly revised and rewritten. In one handsome octavo volume of 467 pages, with two colored plates. Cloth, $3.00. It is impossible to peruse these interesting chap- ; method of interpretation. Guided by an enlight- ters without being convinced of the author's per- ened deduction, the author has reclaimed for feet sincerity, impartiality, and thorough mental | science a most interesting domain in psychology, grasp. Dr. Tuke has exhibited the requisite ; previously abandoned to charlatans and empirics, amount of scientific address on all occasions, and . This book, well conceived and well written, must the more intricate the phenomena the more firmly commend itself to every thoughtful understand- has he adhered to a physiological and rational ' ing. — New York Medical journal, September 0,1884. CLOUSTON, THOMAS S., M. D., F. It. C. P., L. R. C. S., Lecturer on Mental Diseases in the University of Edinburgh. Clinica? Lectures on Mental Diseases. With an Appendix, containing an Abstract of the Statutes of the United States and of the Several States and Territories re- lating to the Custody of the Insane. By Charles F. Folsom, M. D., Assistant Professor of -Mental Diseases, Medical Department of Harvard University. In one handsome octavo volume of 541 pages, illustrated with eight lithographic plates, four of which are beautifully colored. Cloth, S4. The practitioner aa well as the student will ac- cept the plain, practical teaching of the author as a forward step in the literature of insanity. It is refreshing to find a physician of Dr. Clouston's experience and high reputation giving the bed- side notes upon whirl, his experience has been founded and his mature judgment established. Such clinical observations cannot but be useful to the general practitioner in guiding him to a diag- ■id indicating the treatment, especially in many obscure and doubtful cases of mental dis- ease. To the American reader Dr. Folsom's Ap- pendix adds greatly to the value of the work, and will make it a desirable addition to even- library. — Amen- ogical Journal, July, 1884. 'Dr. Folsom's Abstract may also be obtained separately in one octavo volume of Cloth, $1.50. SAVAGE, GEORGE H., M. D., hi et i • r oi 1 1 Hospital, 1 1 Insanity and Allied Neuroses, Practical and Clinical. In one 12mo. vol- ume ot' 551 pages, with IS typical illustrations. Cloth, f 2.00. Just ready. See Series of Clinical Man wah, page 3. As a handbook, a Kuide to practitioners and atu- common •■rywhere apparent. We re- dents, the book fulfils an admirable purpose. The many forms of insanity are described with char- acteristic clearness, the illustra :e care- fully selected, and as regards treatment, sound it l>r. Savage has written an excellent manual for the practitioner and student. — Am- i riean Journal of Insanity, April, 1885. FLAYFAIR, W. S., 31. D., F. R. C. P., The Systematic Treatment of Nerve Prostration and Hysteria. In one handsome small V2mo. volume of 97 pages. Cloth, $1.00. Blandford on Insanity and its Treatment: Lectures on the Treatment, Medical and Legal, of Insane Patients. In one very handsome octavo volume. 20 Lea Brothers & Co.'s Publications — Surgery. GROSS. S. D., 31. D., LL. D., D. C. L. Oxon., XI. JD. Cantab,, Emeritus Professor of Surgery in the Jefferson Medical College of Philadelphia. A System of Surgery : Pathological, Diagnostic, Therapeutic and Operative. Sixth edition, thoroughly revised and greatly improved. In two large and beautifully- printed imperial octavo volumes containing 2382 pages, illustrated by 1623 engravings. ugly bound in leather, raised bands, $15; half Russia, raised bands, $16. Dr. • " of Surgery has long been the material has been introduced, and altogether the Btandard work on that subject for students and distinguished author has reason to be satisfied practitioners.— -London Lancet, May 10, 1884 that he ha« placed the work fully abreast of the The work as a whole needs no commendation, state of our knowledge. — Med. Retard, Nov. 18, 1882. Hany years ago it earned for itself the enviable rep- : His System of Surgery, which, since its first edi- utati'on of the leading American work on surgery, ' tion in 1859, has been a standard work in this and it is still capable of maintaining that standard, country as well as in America, in "the whole The reason for this need only be mentioned to be j domain of Burgery," tells how earnest and labori- appreciated. The author has always been calm ous and wise a surgeon lie was how thoroughly and judicious in his statements, has based his eon- he appreciated the work done by men in other elusions on much study and personal experience, countries, and how much he contributed to pro- has been able to grasp his subject in its entirety, ' mote the science and practice of surgery in his and, above all, has conscientiously adhered to j own. There has been no man to whom America truth and fact, weighing the evidence, pro and j is so much indebted in this respect as the Nestor con, accordingly. A considerable amount of new ! of surgery. — British Medical Journal, May 10, 1884. ASHHTJRST, JOHN, Jr., 31. D., Professor of Clinical Surgery, Univ. of Penna., Surgeon to the Episcopal Hospital, Philadelphia. The Principles and Practice of Surgery. Fourth edition, enlarged and revised. In one large and handsome octavo volume of about 1100 pages, with about 575 illustrations. Shortly. GOULD, A. REARCE, M. S., 31. B., F. R. C. 8., stant Surgeon to Middlesex Hospital. Elements of Surgical Diagnosis. In one pocket-size 12mo. volume of 589 pages. Cloth, $2.00. \Tust ready. See Students' Series of Manuals, page 3. The student and practitioner will find the | and if practitioners would devote a portion of their leisure to the study of it, they would receive immense benefit in the way of refreshing their knowledge and bringing it up to the present state of progress. — Cincinnati Medical News, Jan., 1885. principles of surgical diagnosis very satisfactorily set forth with all unnecessary verbiage elimi- nated. Every medical student attending lectures should have a copy to study during the intervals, GIBNEY, V. R., M. D., Surgeon to the Orthopcedic Hospital, New York, etc. Orthopaedic Surgery. For the use of Practitioners and Students. In one hand- some octavo volume, profusely illustrated. Preparing. ROBERTS, JOHN B., A. 31., M. D., Lecturer on Anatomy and on Operative Surgery at the Philadelphia School of Anatomy. The Principles and Practice of Surgery. For the use of Students and Practitioners of Medicine and Surgery. In one very handsome octavo volume of about 500 pages, with many illustrations. Preparing. BELLAMY, EDWARD, F. R. C. S., Surgeon and Lecturer on Surgery at Charing Cross Hospital, London. Operative Surgery. Shortly. See Students' Series of Manuals, page 3. ST13ISON, LEWIS A., B. A., 31. D., Prof, of Pathol. Anat. at the Univ. of the City of Nexo York, Surgeon and Curator to Bellevue Hosp. A Manual of Operative Surgery. New (second) edition. In one very hand- some royal 12mo. volume of about 500 pages, with about 350 illustrations. Cloth, $2.50. Shortly. A notice of the previous edition is appended. This volume is devoted entirely to operative sur- 1 every student should possess one. This work gery, a I to fai liliarize the student does away with the necessity of pondering over with the details of operations and the different larger works on surgery for descriptions of opera- modes oing them. The work is hand- tions.asii pr nta in a nutshell what is wanted ■omely illustrated, and the de are clear | by >a without an elaborate search to and well-drawn. It is a clever and useful volume; | find it.— Maryland Medical Journal, August, 1878. SARGENTONBA urn OTHER OPERA- I PIRRIE'8 PRINCIPLES AND PRACTICE OF TION8 OF MINOR 8URGERY. New edition, I SURGERY. Edited by John Nbill, M. D. In withaCha tlitary surgery. One 12mo. | one 8vo. vol. of 784 pp. with 316 illus. Cloth, 83.75. volumeof '888 pages, with 187 cuts. Cloth, $1.75. COOPER'S LECTURES ON THE PRINCIPLES MILLER'S PRINCIPLES OF SURGERY. Fourth ' K y U PRACTICE OF SURGERY. Inone 8vo. vol. American from the third Edinburgh edition. In | of767oa«ea cloth 8'' f instruction is divided Into five the methods of affording first treatment in cases The first, or introductory of frost-bite, of drowning, of suffocation, of loss of consciousness and of poisoning are described; and the fifth lecture beaches how injured p may be most safely and easily transported to their co a medical man, or to a hospital. The illustrations in the hook are clear andgood.- sections or lectui lecture, gives a brief account of the structure and organization of the human body, illustrated by clear, -ititahle diagrams. The second teaches how e judicious help in ordinary injuries — contu- , wounds, hemorrhage and poisoned wounds. third treats of first aid in eases of fracture col Times and Gazette, Nov. 4, 1882 and of dislocations, In sprains and in burns. Next, TREVES, FREDERICK, F. J!. C. S.. .1 v- on to and Lecturer on Surgery at the London Hospital. Intestinal Obstruction. In one pocket-size l2mo. volume of 522 pages, with 60 illustrations. Limp cloth, blue edges, $2.00. page 3. indard work on a subject that has not been so comprehensively treated by any contemporary i i w liter, lis completeness rendei review difficult, since evi deserves mi- •< of Clinical Manuals, author in a few paragraphs. Intes- tinal Obstruction is a work that will prove of equal value to tioner, the studei •j, sur- nute attention, and it is impossible to do thorough t : mo/, Jan. 31, BALL, CHARLES B., M. Ch., Hub., F. R. C. S. E., Hospital, Dublin. Diseases of the Rectum and Anus. Jn one 12mo. volume of 550 page*. Preparing. i of Clinical Manual.', page 3. HRIITT, ROBERT, M. R. C. S.. etc. The Principles and Practice of Modern Surgery. From the eighth London edition. In one 8vo. volume of 687 pages, with 432 illus. Cloth, $4; leather, $5. 22 Lea Brothers & Co.'s Publications — Surgery. HOLMES, TIMOTHY, 31. A., Surgeon and Lecturer on Surgery at St. George's Hospital, London. A System of Surgery ; Theoretical and Practical. EN TREATISES BY VAEIOUS AUTHORS. American edition, thoroughly revised and re-edited by John II. Packard, M. D., Surgeon to the Episcopal and St. Joseph's Hospitals, Philadelphia, assisted by a corps of thirty-three of the most eminent American surgeons. In three large and very handsome imperial octavo volumes containing 3137 double- columned pages, with 979 illustrations on wood and 13 lithographic plates, beautifully colored. Price per volume, cloth, $6.00 ; leather, £7.00 ; half Russia, $7.50. Per set, cloth, $18.00 ; leather, $21.00 ; half Russia, $22.50. Sold only by subscription. Volume I. contains General Pathology, Morbid Processes, Injuries in Gen- eral, Complications of Injuries and Injuries of Regions. Volume II. contains Diseases of Organs of Special Sense, Circulatory Sys- tem, Digestive Tract and Genito-Urlnary Organ>. Volume III. contains Diseases of the Respiratory Organs, Bones, Joints and Muscles. Diseases of the Nervous System, Gunshot Wounds, Operative and Minor Surgery, and Miscellaneous Subjects (including an essay on Hospitals). This great work, issued some years sin£e in England, has won such universal confi- dence wherever the language is spoken that its republication here, in a form more thoroughly adapted to the wants of the American practitioner, has seemed to be a duty owing to the profession. To accomplish this, each article has been placed in the hands of a gentleman specially competent to treat its subject, and no labor has been spared to bring each one up to the foremost level of the times, and to adapt it thoroughly to the practice of the country. In certain cases this bus rendered necessary the substitution of an entirely new essay for the original, as in the case of the articles on Skin Diseases, on Diseases of the Absorbent System, and on Anaesthetics, in the use of which American practice differs from that of England. The same careful and conscientious revision has been pursued throughout, leading to an increase of nearly one-fourth in matter, while the series of illustrations has-been nearly trebled, and the whole is presented as a complete exponent of British and American Surgery, adapted to the daily needs of the working practitioner. In order to bring it within the reach of eveiy member of the profession, the five vol- umes of the original have been compressed into three by employing a double-columned royal octavo page, and in this improved form it is offered at less than one-half the price of the original. It is printed and bound to match in every detail with Reynolds' System of Medi- cine. The work will be sold by subscription only, and in due time every member of the profession will be called upon and offered an opportunity to subscribe. The authors of the original English edition are the library of any medical man. It is more wieldly men of the front rank in England, and Dr. Packard and more useful than the English edition, and with has been fortunate in securing as his American its companion work — "Reynolds' System of Medi- coadjutors such men as Bartholow, Hyde, Hunt, cine" — will well represent the present state of our Conner, Stimson, Morton, Hodgen, Jewell and science. One who is familiar with those two works their colleagues. As a whole, the work will be will be fairly well furnished head-wise and hand- solid and substantial, and a valuable addition to wise. — The Medical News, Jan. 7, 1882. STIMSON LEWIS A., B. A., M. &., Professor of Pathological Anatomy at the University of the City of New York, Surgeon and Curator to BeUevue Hospital, Surgeon to the Presbyterian Hospital, yew York, etc. A Practical Treatise on Fractures. In one very handsome octavo volume of 598 pages, with 360 beautiful illustrations. Cloth, §4.75 ; leather, $5.75. The author has given to the medical profession l the surgeon in full practice. — If. O. Medical and in this treatise on fractures what is likelv to be- Surgical Journal, March, 1883. come a standard work on the subject. It is certainly The author gives j Q e)ear i anguage all that the not surpassed by any work written m the English, practjcal surge on need know of the science of or, for that matter, any other language. The au- fracture s, their etiology, symptoms, processes of thor tells us in a short, concise and comprehensive uniou an ' d treatment, according to the latest de- manner, all that is known about his subject. There ve lopments. On the basis of mechanical analysis us nothing scanty or superficial about it as in most the author accurately and clearly explains the other treatises; on the contrary, everything is thor- c i miea i features of fractures, and by the same ough. The chapters on repair of fractures and their me thod arrives at the proper diagnosis snd rational treatment show nun not only to be a profound stu- treatment A thorough explanation of the patho- dent, but likewise a practical surgeon and patholo- logk . al anatomv and 6 a careful description of the gist. His mode of treatment of the different fract- v ^ rionii methods of procedure make the book full uresis eminently sound and practical. We consider of vahle for e przctitioneT.-Centralblatt fur this work one of the best on fractures ; and it will chirurgie. May 19, 1883. be welcomed not only as a textrbook, but also by MARSH, HOWARD, F. It. C. S., Senior Assistant Surgeon to and Lecturer on Anatomy at St. Bartholomew's Hospital, London. Diseases of the Joints. In one 12mo. volume. Preparing. See Series of Clinical Manuals, page 3. FICK, T. EICKEREJYG, F. It. C. 8., Surgeon to and Lecturer on Surgery at St. George's Hospital, London. Fractures and Dislocations. In one 12mo. volume. Preparing. See Series of Clinical Manuals, page 3. Lea Brothers & Co.'s Pubi0:ations — Frac., Disloc, Ophthal. 23 HAMILTON, FRANK H, M. D., LL. D., Surgeon to Bellevue Hospital, Xew York. A Practical Treatise 911 Fractures and Dislocations. Seventh edition, thoroughly revised and much improved. In one very handsome octavo volume of 998 pages, with 379 illustrations. Cloth, So. 50: leather, $6.50; very handsome half Russia, open hack, $7.00. Just read;/. Hamilton's great experience and wide acquaint- cent work, and especially of the recorded re- ance with the literature of the subject have enabled searches and improvements made by the author him to complete the labors of Malgaigne and to himself and his countrymen. — British Medical place the reader in possession of the advances Journal, May 9, 1S85. made during thirty years. The editions have fol- | With its first appearance in 1859, this work took lowed each other rapidly, and they introduce us rank among the classics in medical literature, to the methods of practice, often so wise, of his and has ever since been quoted by surgeons the American colleagues. More practical than Mai- : world over as an authority upon the topics of gaigne's work, it will serve as a valuable guide to which it treats. The surgeon, if one can be found the practitioner in the numerous and embarrass- who does not already know the work, will find it ing cases which come under his observation. — I scientific, forcible and scholarly in text, exhaustive i Generates de MSdecine, Paris, Nov. 1884. in detail, and ever marked by a spirit of wise con- This work, which, since its first appearance servatism. — Louisville Medical News, Jan. 10, 1885. twenty-five years ago, I through many. For a quarter of a century the author has been editions, and been much enlarged, may now be elaborating and perfecting his work, so that it fairly regarded as the authority of refer- now stands a< the best ol its kind in any lan- ence on the subjects of fractures and dislocations, gnage. As a text-book and as a book of reference Each successive edition has been rendered of and guidance for practitioners it is .-im ply invalu- greater value through the addition of more re- able. — yew Orleans Med. and Swg.JownCl, Nov. 1881. JTILER, HENRY E., F. R. C. S., Senior Ass' t Surgeon, Royal Westminster Ophthalmic Hasp. ; late Clinical A*.: ( , London. A Handbook of Ophthalmic Science and Practice. In one handsome octavo volume of 460 pages, with 125 woodcuts, 27 colored plates, and selections from the Test-types of Jae-.r and Snellen. Cloth, $4.50; leather, $5.50. Just ready. This work is distinguished by the great num.- and typical illustrations of all important eye ber of colored plates which appear in it for illus- affections, placed in juxtaposition, so as to be trating various pathological conditions. They are grasped at a glance. Beyond a doubt it is the very beautiful in appearance, and have been best illustrated handbook of ophthalmic science executed with great care a- to accuracy. An ex- which has ever appeared. Then, what is still aminatiou of the work shows it to be one of high better, these illustrations are nearly all original. ling, one that will be regarded as an authority We have examined this entire work with great among le treatment recom- care, and it the commonly accepted uch as the author has learned from views of advanced ophthalmologi-ts. We can most actual experience to be the best. — Cincinnati Medi- heartily commend this book to all medical stu- cal Neu dents, practitioners and specialists. — Detroit It presents to the student concise descriptions : Lancet, Jan. 1885. WELLS, J. SOELBERG, F. R. C. S., of Ophthalmology in King's College Hospital, London, etc. A Treatise on Diseases of the Eye. Fourth American from the third London edition. Thoroughly revised, with copious additions, by Charles S. Bull, M.D., Surgeon and Pathologist to the New York Eye and Ear Infirmary. In one large octavo volume of 'ages, with 257 illustrations on wood, six colored plates, and selections from the Test- ■-f Jaeger and Snellen. Cloth, $5.00; leather, $6.00; half Eussia, $6.50. The present edition appears in less than three shows the fidelity and thoroughness with which years since the publication of the last American the editor has accomplished his part of the work. edition, and yet, from the numerous recent inves- The illustrations throughout are good This edi- tigatione that have been made in this branch of tion can be recommended to all as a complete ae. many changes and additions have been treatise on diseases of the eye, than which proba- required to meet the present scope of knowledge bly none better exists. — Medtcal Record, Aug. 18, '83. upon this subject. A critical examination at once | NETTLESHIF, EDWARD, F. R. C. S., Ophf ;. and Lect. on Ophth. Surg, at St. Thomas' Hospital, London. The Student's Guide to Diseases of the Eye. Second edition. With a chap- ter on the Detection of Color-Blindness, by William Thomson, M. I)., Ophthalmologist to the Jefferson Medical College. In one royal ll!ino. volume of 416 pages, with 138 illustrations. ( I This admirable guide bids fair to become the j and well chosen. This book, within the short corn- favorite text-book on ophthalmic surgery with stu- pass of about 400 pages, contains a lucid exposition dents and general practitioners. It bears through- of the modern aspect of ophthalmic science. — out the imprint of sound judgment combined with Medical Record, June 23, 1883. vast experience. The illustrations are numerous | BROWNE, EDGAR A., Surgeon to the Liverpool Eye and Ear Infirmary and to the Dispensary for Skin Diseases. How to Use the Ophthalmoscope. Being Elementary Instructions in Oph- thalmoscopy, arranged for the use of Students. In one small royal 12mo. volume of 116 with 35 illustrations. Cloth, $1.00. LAW80N ON INJURIES TO THE EYE, ORBIT j titioners. Second edition. In one octavo vol- AND EYELIDS: Their Immediate and Remote ume of 227 pages, with 65 illust. Cloth, 32.75. Effects. 8vO.,404pp.,92iUU8. (loth, $3.50. . CARTER'S PRACTICAL. TREATISE ON DISEAS- LAURENCE AND MOON'S HANKY BOOK OF E80FTHEEYE. Edited by John Greek, M.D. OPHTHALMIC SURGERY, for the use of Prac- In one handsome octavo volume. Lea Brothers & Co.'s Publication^— Otol., Urin. l>is.,Dent. BURNETT, CHARLES H., A. 31., 31. !>., Prof essor of Otology in ■ Iphia Polyclinic; President of the American Otological Society. The Ear, Its Anatomy, Physiology and Diseases. A Practical Treatise for the use of Medical Students and Practitioners. New (second) edition. In one handsome octavo volume of 580 pages, with 107 illustrations. Cloth, $4.00; leather, $5.00. Just ready. We note with pleasure the appearance of a second carried out, and much new matter added. Dr. edition of thl work. When it first came ! Burnett's work must be regarded ;i< a very valua- out it was accepted by the profession as one of ble contribution to aural surgery, not only on the standard works on modern aural Burgeryin account of its comprehensiveness, but because it the English language; andin bis second edition contains the results of the careful personal observa- Dr. Burnett has fully maintained hi* reputation, tion and experience of this eminent aural surgeon. for the book is replete with valuable information | —London Lancet, Feb. 21, 1885. and suggestions. The revision has been carefully | FOLITZER, ADAM, Imperial- Royal Prof, of Aural Therap. in the Univ. of Vienna. A Text-Book Of the Ear and its Diseases. Translated, at the Author's re- quest, by James Patterson Casselis, M. D., M. R. C. S. In one handsome octavo vol- ume of 800 pages, with 257 original illustrations. Cloth, $5.50. The work itself we do not hesitate to pronounce section, and this again by the pathological physi- the best upon the subject of aural diseases which , ology, an arrangement which serves to keep up the has ever appeared, systematic without being too interest of the student by showing the direct ap- ditfuse on obsolete subjects, and eminently prac- i plication of what has preceded to the study of dis- tk'a! in everysense. The anatomical descriptions i ease. The whole work can be recommended as a of each separate division of the ear are admirable, reliable guide to the student, and an efficient aid and profusely illustrated by woodcuts. They are ! to the practitioner in his treatment. — Boston Med- followed immediately by the physiology of the ; ical and Surgical Journal, June 7, 1883. ROBERTS, WILLIA3I, 31. L>., Lecturer on Medicine in the Manchester School of Medicine, etc. A Practical Treatise on Urinary and Renal Diseases, including Uri- nary Deposits. Fourth American from the fourth London edition. In one hand- some octavo volume of 609 pages, with 81 illustrations. Cloth, $3.50. Just ready. The peculiar value and finish of the book are j directly or indirectly to the diagnosis, prognosis derived from its resolute maintenance of a clinical i and treatment of urinary diseases, and possesses and practical character. This volume is an un- a completeness not found elsewhere in our laa- rivalled exposition of everything which relates | guage. — The Medical Chronicle, July, 1885. q» GROSS, S. TJ., 31. T>., LL. TJ., TJ. C. L., etc. A Practical Treatise on the Diseases, Injuries and Malformations of the Urinary Bladder, the Prostate Gland and the Urethra. Third edition, thoroughly revised by Samuel W. Gross, M. D., Professor of the Principles of Surgery and of Clinical Surgery in the Jefferson Medical College, Philadelphia. In one octavo volume of 574 pages, with 170 illustrations. Cloth, $4.50. MORRIS, HE WRY, 31. B., F. R. C. S., Sutgeon to and Lecturer on Surgery at Middlesex Hospital, I^ondon. Surgical Diseases of the Kidney. In one 12mo. volume. Preparing. See Series of Clinical Manuals; page 3. LUCAS, CLEMENT, M. B., B. S., F. R. C. S., Senior Assistant Surgeon to Guy's Hospital, London. Diseases of the Urethra. In one 12mo. volume. Preparing. See /Series of Clinical Manuals, page 3. TH03IFSON, SIR JSENRY, Surgeon and Professor of Clinical Surgery to University College Hospital, London. Lectures on Diseases of the Urinary Organs. Second American from the third English edition. In one 8vo. volume of 203 pp., with 25 illustrations. Cloth, $2.25. By the Same Author. On the Pathology and Treatment of Stricture of the Urethra and Urinary Fistulse. From the third English edition. In one octavo volume of 359 pages, with 47 cuts and 3 plates. Cloth, $3.50. COLE3IAN, A., L. R. C. P., F. R. C. S., Exam. L. I>. S., Senior Dent. Surg, and Lect. on Dent. Surg, at St. Bartholomew's Hosp. and the Dent. Hasp., London. A Manual of Dental Surgery and Pathology. Thoroughly revised and adapted to the use of American Students, by Thomas C. Stellwagen, M. A., M. D., D. I). 8., Prof, of Physiology at the Philadelphia Dental College. In one handsome octavo volume of 412 pages, with 331 illustrations. Cloth, $3.25. BASHAM ON RENAL DISEASES: A Clinical I one 12mo. vol. of 304 pages, with 21 illustrations. Guide to their Diagnosis and Treatment. In | Cloth, $2.00. Lea Brothers & Co.'s Publications — Venereal, Impotence. 25 BU3ISTEAI). F. J., and TAYLOR, B. W., 31. !>., LL. &., A. M., 31. !>., Late Professor of Venereal Diseases Surgeon to Charity Hospital, yen- York, Prof, of at th< • and d Skin Diseases in tht University of Surgeons, New York, etc. f the Am. Dertnatologieal Asvn. The Pathology and Treatment of Venereal Diseases. Including the results of recent Investigations upon the subject. Fifth edition, revised and largely re- written, by Dr. Taylor. In one large and handsome octavo volume of 898 pages with 139 illustrations, and thirteen chrome-lithographic figures. Cloth, $4.75; leather, $5.75; very handsome half Russia, $6.25. It is a splendid record of honest labor, wide ; The character of this standard work is so well research, just comparison, careful scrutiny an., Professor of the Principles of Surgery and of Clinical Surgery in the Jefferson Medical College. A Practical Treatise on Impotence, Sterility, and Allied Disorders of the Male Sexual Organs. Second edition, thoroughly revised. In one very hand- some octavo volume of 168 pages, with 16 illustrations, (loth, $1.50. The author of this monograph is a man of posi- This work will derive value from the high stand- tive convictions and vigorous style. This isiusti- ing of its author, aside from the fact of its passing fied by his experience and by his study, which has so rapidly into its second edition. This is, indeed, gone hand in hand with his experience. In regard a book that every physician will be glad to place to the various organic and functional disorders of in his library, to be read with profit to himself, the male generative apparatus, he has had ex- and with incalculable benefit to his patient. Be- ceptional opportunities for observation, and his Bides the subjects embraced in the title, which are book shows that he has not neglected to compare treated of in their various forms and degrees, his own views with those of other authors. The spermatorrhoea and prostatorrhcea are also fully result is a work which can be safely recommended considered. The work is thoroughly practical in to both physicians and surgeons as a guide in the character, and will be especially useful to the treatment of the disturbances it refers to. It is general practitioner. — Medical kecord, Aug. is, the best treatise on the subject with which we are 1883. acquainted. — The Medical News, Sept. l, 1883. CULLEBIEB, A., & BU3LSTEAF), F. J., 3I.F)., LL.JD., Surgeon to the II6pital du Midi. Late Professor at Pi nereal Diseases in the College of Physicians and Surgeons, Xcu figures, beautifully colored, many of them the size of life. Strongly bound in cloth, $17.00. A specimen of the plates and text sent by mail, on receipt of 25 cts. BILLON 8YPHILI8 AND LOCAL CONTAGIOUS FORMS OF LOCAL DISEASE AFFECTING DISORDERS. In one 8vo vol. of 479 p. Cloth, $3.25. PRINCIPALLY THE ORGANS OF GENERA- LEE'S LECTURES ON SYPHILIS AND SOME TION. In one Svo. vol. of -J4<. pages. Cloth, $2.». 26 Lea Brothers & Co.'s Publications — Diseases of Skin. HYDE, J. JFEttirS, A. 31., 31. &., Dermatology and Venereal Diseases in Rush Medical College, Chicago. A Practical Treatise on Diseases of the Skin. For the use of Students and Practitioners. In one handsome octavo volume of 570 pages, with 66 beautiful and elab- orate illustrations, doth, $4.25; leather, $5.25. The author has given the student and practi- ciao in active practice. In dealing with these tioner a work admirably adapted to the wants of questions the author leaves nothing to the pre- eacli. We can heartilv commend the book as a sumed knowledge of the reader, but enters thor- valuable addition to our literature and a reliable oughly into the most minute description, bo that guide to students and practitioners in their studies one is not only told what should be done under and practice.— Am. Journ, f Med. Set., July, 1883. given conditions but how to do it as well. It is Especially to be praised are the practical sug- therefore in the best sense "a practical treatise." gestiins as' to what may be called the common- i That it is comprehensive, a glance at the index sense treatment of eczema. It is quite impossible will show. — Maryland Medical Journal, July 7, 1883, to exaggerate the judiciousness with which the Professor Hyde has long been known as one of formula? for the external treatment of eczema are | the most intelligent and enthusiastic reprcsenta- selected, and what is of equal importance, the full tives of dermatology in the west. His numerous and clear instructions for their use.— London Medi- contributions to the literature of this specialty «i/ Times and Gazette, July 28, 1883. have gained for him a favorable recognition as a The work of I»r. Hyde" will be awarded a high < careful, conscientious and original observer. The position. The student of medicine will find it remarkable advances made in our knowledge of peculiarly adapted to his wants. Notwithstanding diseases of the skin, especially from the stand- the extent of the subject to which it is devoted, j point of pathological histology and improved vet it is limited to a single and not very large vol- I methods of treatment, necessitate a revision of ume. without omitting a proper discussion of the the older textrbooks at short intervals in order to topics. The conciseness of the volume, and the | bring them up to the standard demanded by the setting forth of only what can be held as facts will march of science. This last contribution of Dr. also make it acceptable to general practitioners. ' Hyde is an effort in this direction. He has at- — Cincinnati Medical News, Feb. 1883. ' tempted, as he informs us, the task of presenting The aim of the author has been to present to his in a condensed form the results of the latest ob- readers a work not only expounding the most : servation and experience. A careful examinatiod modern conceptions of his subject, but presenting of the work convinces us that he has accomplishen what is of standard value. He has more especially his task with painstaking fidelity and with a cred- devoted its pages to the treatment of disease, and ; itable result. — Journal of Cutaneous and Venereal by his detailed descriptions of therapeutic meas- i Diseases, June, 1883. ures has adapted them to the needs of the physi- FOX, T., M.D., F.R. C. P., mid FOX, T. C, B.A., M.R. C.S., Physician to the Department for Skin Diseases, Physician for Diseases of the Skin to the University College Hospital, London. Westminster Hospital, London. An Epitome of Skin Diseases. With Formulae. For Students and Prac- titioners. Third edition, revised and enlarged. In one very handsome 12mo. volume of 238 pages. Cloth, $1.25. The third edition of this convenient handbook manual to lie upon the table for instant reference, calls for notice owing to the revision and expansion Its alphabetical arrangement is suited to this use, which it has undergone. The arrangement of skin I for all one has to know is the name of the disease, diseases in alphabetical order, which is the method and here are its description and the appropriate of classification adopted in this work, becomes a treatment at hand and ready for instant applica- positive advantage to the student. The book is tion. The present edition has been very carefully one which we can strongly recommend, not only revised and a number of new diseases are de- to students but also to practitioners who require a scribed, while most of the recent additions to compendious Bummary of the present state of dermal therapeutics find mention, and the formu- dermatology.— Br Journal, July 2, 1883. ; lary at the end of the book has been considerably We cordially recommend Fox's Epitome to those augmented.— The Medical News, December, 1883. whose time is limited and who wish a handy | MORRIS, 3IALCOLM, M. &., Joint Lecturer on Dermatology at St. Mary's Hospital Medical School, London. Skin Diseases ; Including their Definitions, Symptoms, Diagnosis, Prognosis, Mor- bid Anatomy and Treatment. A Manual for Students and Practitioners. In one 12mo. volume of 316 pages, with illustrations. Cloth, $1.75. To physicians who would like to know something , for clearness of expression and methodical ar- about skin diseases, so that when a patient pre- rangement is better adapted to promote a rational sents himself for relief they can make a correct conception of dermatology — a branch confessedly difficult and perplexing to the beginner. — St Louis Courier of Medicine, April, 1880. The writer has certainly given in a small compass a large amount of well-compiled information, and his little book compares favorably with any other which has emanated from England, while in many points he has emancipated himself from the stub- bornly adhered to errors of others of his country- men." There is certainly excellent material in the book which will well repay perusal.— Boston Med. and Surg. Journ., March, 1880. diagnosis and prescribe a rational treatment, we unhesitatingly recommend this little book of Dr. Morris. The affections of the skin are described in a terse, lucid manner, and their several charac- teristics so plainly set forth that diagnosis will be easy. The treatment in each case is such as the experience of the most eminent dermatologists ad- vises. — Cincinnati Medical Wi »., April, 1880. This is emphatically a learner's book; for we can safely say, that in t"he. whole range of medical literature there is no book of a like scope which WILSOJV, FRAS3IUS, F.R.S. The Student's Book of Cutaneous Medicine and Diseases of the Skin. In one handsome small octavo volume of 535 pages. Cloth, $3.50. SILLIER, THOMAS, M. &., Physician to the Skin Department of University College, London. Handbook of Skin Diseases; for Students and Practitioners. Second Ameri- can edition. In one 12mo. volume of 353 pages, with plates. Cloth, $2.25. Lea Brothers & Co.'s Publications — Dis. of Women. 27 AN AMERICAN SYSTEM OF GYNAECOLOGY. A System of Gynaecology, in Treatises by Various Authors. Edited by Matthew D. Mann, M. D., Professor of Obstetrics and Gynaecology in the Uni- versity of Buffalo, N. Y. In two handsome octavo volumes, richly illustrated. In active preparation. LIST OF CONTRIBUTORS. WILLIAM H. BAKER, M. D., FORDYCE BARKER, M. D., ROBERT BATTEY, M. D., SAMUEL C. BUSEY, M. D., HEXRY F. CAMPBELL, M. D., HENRY C. COE, M. D., E. C. DUDLEY, M, D, GEORGE J. ENGELMANX, M. D., HEXRY F. GARRIGUES, M. D., WILLIAM GOODELL, M. !>., EGBERT H. GRANDIX, M. D., SAMUEL W. GROSS, M. D., JAMES B. HUNTER, M. D., A. REEVES JACKSON, M. D., EDWARD W. JENKS, M. D., WILLIAM T. LUSK, M. D., MATTHEW D. MAXX, M. D., ROBERT B. MAURY, M. D., PAUL F. MUNDE, M. D., C. D. PALMER, 31. D., WILLIAM M. POLK, M. D., THADDEUS A. REAMY, M. D., A. D. ROCKWELL, M. D., ALEX. J. C. SKEXE, M. D., R. BTANSBURY SUTTON, A. M., M. D. T. GAILLARD THOMAS, M. D., ELI VAX DE WALKER, M. D., W. GILL WYLIE, M. D. THOMAS, T. GAILLARD, M. &., Professor of Diseases of Women in the College of Physicians and Surgeons, N. 7. A Practical Treatise on the Diseases of Women. Fifth edition, thoroughly revised and rewritten. In one large and handsome octavo volume of 810 pages, with 266 illustrations. Cloth, $5.00 ; leather, $6.00 ; very handsome half Russia, raised bands, $6.50. The words which follow " fifth edition" are in vious one. As a book of reference for the busy this ease no mere formal announcement. The practitioner it is unequalled. — Boston Medical any alterations and additions which have been made are .S • ', April 7, 1880. both numerous and important. The attraction It has I teen enlarged and carefully revised. It is and the permanent character of this book lie in a condensed encyclopaedia of gynaecological medi- the clearness and truth of the clinical descriptions , cine. The style of arrangement, the masterly of diseases; the fertility of the author in thera- manner in which each subject is treated, and the peutic resources and the fulness with which the honest convictions derived from probably the details of treatment are described; the definite largest clinical experience in that specialty of any character of the teaching; and last, but not least, in this country, all serve to commend it in the the evident candor which pervades it. We would highest terms to the practitioner. — Nashville jour. also particularize the fulness with which the his- of Med. and Surg., Jan. 1881. tory of the subject is gone into, which makes the That the previous editions of the treatise of Dr. book additionally interesting and gives it value as Thomas were thought worthy of translation into awork of reference.— London Medical Times and German, French, Italian and Spanish, is enough to give it the stamp of genuine merit. At home it de its way into the library of ever3 T obstet- rician and gynaecologist as asafe guide to practice. No small number of additions have been made to the present edition to make it correspond to re- Pacific Metiical Gazette, July 30, 1881. The determination of the author to keep his book foremost in the rank of works on gynaecology is most gratifying. Recognizing the fact that this can only be accomplished by frequent and thor- ough revision, he has spared no pains to make the cent'improvements in treatment. t edition more desirable even than the pre- an'i Surgical Journal, Jan. 1881. EHIS, ARTHUR W.. M. D., Lond., F.R. C.JP., 31. R. C.S., ' . Obstetric Physician to Middlesex Hospital, late Physician to British Lying-in Hospital. The Diseases of Women. Including their Pathology, Causation, Symptoms, Diagnosis and Treatment. A Manual for Students and Practitioners. In one handsome volume of 576 pages, with 148 illustrations. Cloth, $3.00; leather, $4.00. It is a pleasure to read a book so thoroughly The greatest pains have been taken with the good a« this one. The special qualities which are sections relating to treatment. A liberal selection conspicuous are thoroughness in covering the of remei en for each morbid condition, whole ground, clearness of description and con- the strength, mode of application and other details ciseness of statement. Another marked feature of being fully explained. The descriptions of gyna> the book is the attention paid to the details of cofogical manipulations and operations are full, many minor surgical operations and procedures, clear and practical. Much care has also been be- as, for instance, the use of tents, application of stowed on the parte of the book which deal with leeches, and use of hot water injections. These diagnosis— we note especially the pages dealing are among the more common methods of treat- with the differentiation, one from another, of the ment, and yet very little is said about them I kinds of abdominal tumors. The prac- many of the text-books. The book is one to be i titioner will therefore find in this book the kind warmly recommended especially to students and of knowledge he most needs in his daily work, and general practitioners, who need a concise but com- he will be ] leased with the clearness and fulness plete rtsumt of tin t. Specialists, too, of the informaiiou there given.— The Practt will find many useful hints in its pages.— Boston Feb. 1882. Med. and Surg. Journ., March 2, 1882. BARNES, ROBERT, M. D., E. R. C. I*., Obstetric Physician to St. Thomas' Hospital, London, etc. A Clinical Exposition of the Medical and Surgical Diseases of Women. In one handsome octavo volume, with numerous illustrations. New edition. Preparing. WEST, CHARLES, M. I). Lectures on the Diseases of Women. Third American from the third Lon- don edition. In one octavo volume of 543 pages. Cloth, $3.75 ; leather, $4.75. Lea Brothers & Co.'s Publications — Dis. of Women, Midwty. EMMET, THOMAS ADDIS, M. D., LL. D., the Woman's Hospital, Xeic York, etc. The Principles and Practice of Gynaecology ; For the use of Students and Practitioners of Medicine. New | third) edition, thoroughly revised. In one large and vrery handsome octavo volume of B80 pages, with 160 illustrations. Cloth, $5; leather, $6. kre in doabt whether to congratulate the The time has passed when Emi author more than the profession upon the appear- was to be regarded as a book for a single country ance of the third edition of this well-known work, or for a single generation. It has always been his lying, as it does, the life-long experience of aim to popularize gynecology, to bring it within one « ouously distinguished himself easy reach of the general practitioner. The orig- as a bold 8 il operator, and who has inality of the ideas, aside from the perfect con- ition to the specialty, we fidence which we feel in the author's statements, feel sure the profession will not fail to appreciate compels our admiration and respect. We may the privilege thus offered them of perusing the well take an honest pride in Dr. Emmet's work views and practice of the author. His earnestness and feel that his book can hold its own against the of purpose and conscientiousness are manifest, criticism of two continents. It represents all that only his individual experience but is most earnest and most thoughtful in American endeavors to represent the actual state of gynie- gynaecology. Emmet's work will continue to - cal science and art. — British Medical Jour- reflect the individuality, the sterling integrity and nil, May 16, I the kindly heart of itshonored author long after it or tittle of the high praise bestowed upon smaller books have been forgotten. — American the first edition is abated. It is still a book of Journal of Obstetrics, May \ 1885 marked personality, one based upon large clinical Any work on gynaecology by Emmet must experience, containing large and valuable ad- always have especial interest and value. He has ditions to our knowledge, evidently written not for many years* been an exceedingly busy prac- only with honesty of purpose, but with a conscien- titioner in this department. Few men have had tious sense of responsibility, and a book that is at his experience an i opportunities. Asa guide once a credit to its author and to American med- either for the general practitioner or specialist. ical literature. We repeat that it is a book to be it is second to none other. No one can read I. and one that is indispensable to every Emmet without pleasure, instruction and profit. giving any attention to gynaecology. — — Cincinnati Lancet and Clinic, Jan 31, 1885. American Jom s, April, 1885. | DTJXCAX, J. MATTHEWS, 3I.D., LL. D., F. R. S. E., etc. Clinical Lectures on the Diseases of Women ; Delivered in Saint Bar- tholomew's Hospital. In one handsome octavo volume of 175 pages. Cloth, $1.50. They are in every way worthy of their author ; stamp of individuality that, if widely read, as they indeed, we look upon them as among the most certainly deserve to be, they cannot fail to exert a valuable of his contributions. They are all upon wholesome restraint upon the undue eagerness matters of great interest to the general practitioner, with which many young physicians seem bent Some of them deal with subjects that are not, as a upon following the wild teachings which so infest rule, adequately handled in the text-books; others the gynaecology of the present day. — N. Y. Medical of them, while bearing upon topics that are usually Journal, March", 1880. treated of at length in such works, yet bear such a ] MAY, CHARLES H., M. D. Latt i ' Yerk. A Manual Of the Diseases of Women, Containing a concise and systematic exposition of theory and practice. In one 12mo. volume of about 350 pages. In prwa. HODGE, HUGH L., 31. D., Emeritus Professor of Obstetrics, etc., in the University of Pennsylvania. On Diseases Peculiar to Women; Including Displacements of the Uterus. :id edition, revised and enlarged. In one beautifully printed octavo volume of 519 with original illustrations. Cloth, $4.50. By the Same Author. The Principles and Practice of Obstetrics. Illustrated with large litho- graphic plates containing 159 figures from original photographs, and with numerous wood- cuts. In one large quarto volume of 5-12 double-columned pages. Strongly bound in cloth, $14.00. * * * Specimens of the plates and letter-press will be forwarded to any address, free by mail, on receipt of six cents in postage stamps. RA3ISBOTHA31, ERAXCIS H., 31. D. The Principles and Practice of Obstetric Medicine and Surgery; In reference to the Process of Parturition. A new and enlarged edition, thoroughly revised by the Author. With additions by W. V. Keatewg, M. I>.. Professor of Obstetrics, etc., in the Jefferson Medical I Philadelphia. In one large and handsome imperial octavo volume of 040 pages, with „ Professor of Obstetrics and Diseases of Women m the Medical Department of the Columbian Univer- siti/, Washington, !>. C, and in the University of Vermont, etc. A Manual of Obstetrics. Second edition. In one 7ery handsome 12mo. volum« of 331 pages, with 59 illustrations. Cloth, $2.00. Itmu.-r be acknowledged that this is just what ! densed style of composition, the writer has pre- it pretends to be— a sound guide, a portable epit- sented a great deal of what it is well that every a work in which oi matter obstetrician should know and be ready to practice has been presented, leaving out all padding and chaff, and one in which tin- student will find pure « heal i i nutriment — .v. 1 ical ami Surgical Journal, May, l* v !. In a series of short paragraphs and by a Con- or prescribe. The fact that the d< n and for the has been such as to exhaust the first edition in a little over a year and a half speaks well for its popularity. — American Journal of the M. du "/ Scii nr,s t April, I LANHIS, HENRY G. 9 A. 31., 31. D., i in Starling Medical College, Columbus, O. The Management of Labor. In one handsome 12mo. volume of about 300 with 30 illustrations. Sho BARNES, FANCOURT, 31. I)., Obstetric Physician to St. Thomas' Hospital, London. A Manual of Midwifery for Midwives and Medical Students. In one royal 12mo. volume of 197 pages, with 50 illustrations. Cloth, $1.25. PARVIN, THEOPHILUS, 31. D., LL. J).. Professor of ObsU tries and the Diseases of Women and Childri n in the Jefferson Medical College. A Treatise on Midwifery. In one very handsome octavo volume of about 550 pages, with numerous illustrations. In press. PARRY, JOHN S., 31. JD., ~ ' ician to Ho , i Hospital, Vice-President of the Obstet. Society of Philadelphia, Extra- Uterine Pregnancy : Its Clinical History, Diagnosis, Prognosis and Treatment. In one handsome octavo volume oi'"J7 - J pages. Cloth, $2.50. TANNER, TH03IAS HAWKES, M. 2>. On the Signs and Diseases of Pregnancy. First American from the English edition. < Ictavo, 490 pages, with 4 colored plates and 16 woodcuts. Cloth, $4.25. WJNCKEL, F. A Complete Treatise on the Pathology and Treatment of Childbed, For Students and Practitioners. Translated, with the consent of the Author, from the second German edition, by J. R. Chadwick, M. D. Octavo 484 pages. < ''oth, $4.00. 30 Lea Brothers & Co.'s Publications — Midwfy., Dis. Childn. LEISHMsLF, WILLIAM, 31. !>., Regius Professor of Midwifery in the University of Glasgow, etc. A System of Midwifery, Including the Diseases of Pregnancy and the Puerperal State. Third American edition, revised by the Author, with additions by John b. Parry, M. D., Obstetrician to the Philadelphia Hospital, etc. In one large and very handsome octavo volume of 740 pages, -with 205 illustrations. Cloth, $4.50 ; leather, $5.50 ; very handsome half Russia, raised bands, $6.00. The author is broad in his teachings, and dis- j preparation of the present edition the author has cusses briefly the comparative anatomy of the pel- vis and the mobility of the pelvic articulations. The second chapter is devoted especially to the siudy of the pelvis, while in the third the female organs of generation are introduced. The structure and development of the ovum are admirably described. Then follow chapters upon the various subjects embraced in the study of mid- wifery. The descriptions throughout the work are plain and pleasing. It is sufficient to state that in this, the last edition of this well-known work, every recent advancement in this field has been brought forward. — Physician and Surgeon, Jan. 1880. We gladly welcome the new edition of this ex- cellent text-book of midwifery. The former edi- tions have been most favorably received by the profession on both sides of the Atlantic. In the made such alterations as the progress of obstetri- cal science seems to require, and we cannot but admire the ability with which the task has been performed. We "consider it an admirable text- book for students during their attendance upon lectures, and have great pleasure in recommend- ing it. As an exponent of the midwifery of the present day it has no superior in the English lan- guage. — Catiada Lancet, Jan. 1880. To the American student the work before us must prove admirably adapted. Complete in all its parts, essentially modern in its teachings, and with demonstrations noted for clearness and precision, it will gain in favor and be recognized as a work of standard merit. The work cannot fail to be popular and is cordially recommended. — N. O. Med. and Surg. Journ., March, 1880. S3HT1I, J. LEWIS, 31. n., Clinical Professor of Diseases of Children in the Bellevue Hospital Medical College, N. Y. A Complete Practical Treatise on the Diseases of Children. Fifth edition, thoroughly revised and rewritten. In one handsome octavo volume of 836 pages, with illustrations. Cloth, $4.50 ; leather, $5.50 ; very handsome half Russia, raised bands, $6. This is one of the best books on the subject with which we venture to say will be a favorable one which we have met and one that has given us satisfaction on every occasion on which we have consulted it, either as to diagnosis or treatment. It is now in its fifth edition and in its present form is a very adequate representation of the subject it treats of as at present understood. The important Dublin Journal of Medical Science, March, 18S3. There is no book published on the subjects of which this one treats that is its equal in value to the physician. While he has said just enough to impart the information desired by general practi- tioners on such questions as etiology, pathology, subject of infant hygiene is fully dealt with in the : prognosis, etc., he has devoted more attention to early portion of the nook. The great bulk of the , the diagnosis and treatment of the ailments which work is appropriately devoted to the diseases of he so accurately describes ; and such information infancy and childhood. We would recommend is exactly what is wanted by the vast majority of any one in need of information on the subject to , "family physicians." — Va. Med. Monthly, Feb. i882. procure the work and form his own opinion on it, | KEATING, JOHN 31., M. &., Lecturer on the Diseases vf Children at the University of Pennsylvania, etc. The Mother's Guide in the Management and Feeding of Infants. In one handsome 12mo. volume of 118 pages. Cloth, $1.00. Works like this one will aid the physician im- I the employment of a wet-nurse, about the proper mensely, for it saves the time he is constantly giv- food for a nursing mother, about the tonic, effects ing his' patients in instructing them on the sub- of a bath, about the perambulator versus ;the nurses, jects here dwelt upon so thoroughly and prae- arms, and on many other subjects concerning tically. Dr. Keating has written a practical book, which the critic might say, "surely this is obvi- has carefully avoided unnecessary repetition, ana ous," but which experience teaches us are exactly successfully' instructed the- mother in such details the thingsneeded to be insisted upon, with therich of the treatment of her child as devolve upon her. | as well as theyoor.— London Lancet, January, 28 1882. He has studiously omitted giving prescriptions, i a book small in size, written in pleasant style, in and instructs the mother when to call upon the language which can be readily understood by any doctor, as his duties are totally distinct from hers, mother, and eminently practical and safe; in fact —American Journal of Obstetrics, I (ctober, 1881. , a book for which we have been waiting a long Dr. Keating has kept clear of the common fault time, and which we can most heartily recommend of works of this sort, viz., mixing the duties of to mothers as the book on this subject. — New York the mother with those proper to the doctor. There M lal and Obstetrical Review, Feb. 1882. is the ring of common sense in the remarks about OWEN, ED3IUJSTD, 31. B., F. JR. C. S., Surgeon to the Children's Hospital, Oreat Orrnond St., London. Surgical Diseases of Children. In one 12mo. volume. Preparing. See Series of Clinical Mammals, page 3. WEST, CHARLES, 31. D., Physician to the Hospital for Sick Children, London, etc Lectures on the Diseases of Infancy and Childhood. Fifth American from 6th English edition. In one octavo volume of 686 pages. Cloth, $4.50 ; leather, $5.50. By the Same Author. On Some Disorders of the Nervous System in Childhood. In one small 12mo. volume of 127 pages. Cloth, $1.00. CONDIE'S PRACTICAL TREATISE ON THE I vised and augmented. In one octavo volume of DISEASES OF CHILDREN. Sixth edition, re- | 779 pages. Cloth, $5.25 ; leather, «6.25. Lea Brothers & Co.'s Publications — Med. Jmis., Miscel. 31 TIDY, CHARLES MEYMOTT, M. B., F. C. S., Professor of Chemistry and of Forensic Medicine and Public Health at the London Hospital, etc. Legal Medicine. VOLUME II. Legitimacy and Paternity, Pregnancy, Abor- tion, Rape, Indecent Exposure, Sodomy, Bestiality, Live Birth, Infanticide, Asphyxia, Drowning, Hanging, Strangulation, Suffocation. Making a very handsome imperial oc- tavo volume of 529 pages. Cloth, $6.00; leather, $7.00. Volume I. Containing 664 imperial octavo pages, with two beautiful colored plates. Cloth, $6.00 ; leather, $7.00. The satisfaction expressed with the first portion i tables of eases appended to each division of the of this work is in no wise lessened by a perusal of subject, must have cost the author a prodigious the second volume. We find it characterized by amount of labor and research, but they constitute the same fulness of detail and clearness of ex- one of the most valuable features of the book, ■n which we had occasion so highly to com- especially for reference in medico-legal trials. — nif ad in our former notice, and which render it so American Journal of the Medical Sciences, April, 1884. valuable to the medical jurist. The copious TAYLOR, ALFRED S., M. &., Lecturer on Medical Jurisprudence and Chemistry in Guy's Hospital, London. A Manual of Medical Jurisprudence. Eighth American from the tenth Lon- don edition, thoroughly revised and rewritten. Edited by John J. Keese, M. D., Professor of Medical Jurisprudence and Toxicology in the University of Pennsylvania. In one large octavo volume of 937 pages, with 70 illustrations. Cloth, $5.00 ; leather, $6.00 ; half Russia, raised bands, $6.50. only have to seek for laudatory terms. — American Journal of the Medical Sciences, Jan. 1881. This celebrated work has been the standard au- thority in its department for thirty-seven years, both in England and America, in both the profes- sions which it concerns, and it is improbable that it will be superseded in many vears. The work is simply indispensable to every physician, and nearly so to every liberally-educated lawyer, and we heartily commend the present edition to both pro- fessions. — Albany Law Journal, March 2G, 1881. ""-The American editions of this standard manual have for a long time laid claim to the attention of the profession in this country; and the eighth comes before us as embodying tne latest thoughts and emendations of Dr. Taylor upon the subject to which he devoted his life with an assiduity and success which made him facile princeps among English writers on medical jurisprudence. Both the author and the book have made a mark too deep to be affected by criticism, whether it be censure or praise. In this case, however, we should By the Same Author. The Principles and Practice of Medical Jurisprudence. Third edition. In two handsome octavo volumes, containing 1416 pages, with 18S illustrations. Cloth, $10; leather, $12. Just ready. Fi>i years Dr. Taylor was the highest authority in England upon the subject to which he gave 1 attention. His experience was vast, his judgment excellent, and his skill beyond cavil. It is therefore well that the work of one who, as Dr. Stevenson says, had an "enormous grasp of all matters connected with the subject," should be brought up to the present day and continued in its authoritative position. To accomplish this re- sult Dr. Stevenson has subjected it to most careful editing, bringing it well up to the times. — Ameri- can Journal of the Medical Sciences, Jan. 1884. By the Same Author. Poisons in Belation to Medical Jurisprudence and Medicine. Third American, from the third and revised English edition. In one large octavo volume of 788 pages. Cloth, $5.50 ; leather, $6.50. FEFFER, AUGUSTUS J., 31. S., M. B., F. R. C. S., Medicine at the University Forensic Medicine. In one pocket-size 12mo. volume. Preparing. See St '"lints' s '■-, page 3. LEA, HENRY C. Superstition and Force : Essays on The "Wager of Law, The Wager of Battle, The Ordeal and Torture. Third revised and enlarged edition. In one handsome royal 12mo. volume of 652 pages. Cloth, $2.50. '. aloable work La in reality a history of civ- ilization as interpreted by the progress of jurispru- dence. . . In "Superstition and Force" wel I rarvey of the long period intervening I i barbs md civilized ei enment. There is not a chapter in the work that should not be most carefully studied ; and however well versed the reader may be in the science of jurisprudence, he will find much in Mr. I.ea's vol- * which he was previously ignorant. The book is a valuable addition to the literature of so- cial science. — Westminster Pericw, Jan. 1880. By the Same Author. Studies in Church History. The Bise of the Temporal Power— Ben- efit of Clergy — Excommunication octavo volume of 605 pages. Cloth, $! Theauthor is pre-eminently a scholar. He takes up every topic allied with the leadii traces it out to the minutest detail with a wealth of knowledge and impartiality of treatment that compel admiration. The amount of information cisenese and freedom from prejudice, compressed into the book is extraordinary. In no Traveller, Mav 3, 1883. other single volume is the developn cut •>!" the lition. In one very handsome royal - tdy. primitive church traced with so much clearness, and with so definite a perception of complex or conflict] The fifty pages on the growth of the papacy, for instance, are admirable for con- Boston Allen's Anatomy .... American Journal of the Medical Sciences American System of Gynaecology . American System of Practical Medicine •Ash ery .... A&hwell on I Women AttSeld'8 Chemistry .... Ball on the Rectum and Anus Barker's < ibstetrii saj s, Barlow's I'v Heine Barnes' Midwifery *Barnes on Diseases of Women Barn— Obstetric Medicine Bartholow on Electricity :n on Elena! 1 diseases . Bells Comparative Physiology and Anatomy Bellamy's Operative Surgery Bellamy's Surgical Anatomy Blandford on Insanity Bloxam's Chemistry . Bowman's Practical Chemistry *Bristowe's Practice of Medicine . Broadbent on the Pulse Browne nn the Ophthalmoscope Browne on the Throat Bruce's Materia Medicaand Therapeutics Brunton's Matei la Medica and Therapeutics Bryant on the Breast .... •Bryant's Practice of Surgery *Bumstead on Venereal Diseases . ♦Burnett on the Ear .... Butlin on ti.e I ongue .... Carpenter on \i.nse of Alcohol ♦Carpenter's Human Physiology . Carter on the Eye .... Century of American Medicine Chambers on Diet and Regimen Charles' Physiological and Pathological Chem Churchill on Puerperal Fever Clarke and Lock wood's Dissectors' Manual Classen's Quantitative Analysis Cleland's Dissector Clouston on Insanity Clowes' Practical Chemistry Coats' Pathology .... Cohen on the Throat .... Coleman's Dental Surgery Condie on Diseases of Children Cooper's Lectures on Surgery Cornil on Syphilis . •Cornil and Ranvier's Pathological Histology Cullerier's Atlas ol Venereal Diseases Ournow'S Medical Anatomy Dalton on the Circulation . , . •Dalton's HumanPhysiology Dalton's Topographical Anatomy of the Brain Davis' Clinical Lectures Draper's Medical Physics Drum's Modern Surgery Duncan on Diseases of Women •Dunglison'8 Medical Dictionary . Edis on Diseases of Won. en . Ellis' Demonstrations of Anatomy Emmet's Gynaecology •Erichsen's System of Surgery Esmarch's Early Aid in Injuries and Accid'ts Farquharson's Therapeutics and Mat. Med. Fenwick's Medical Diagnosis Finlayson's Clinical Diagnosis Flint on Auscultation and Percussion Flint on Phthisis .... Elint on Physical Exploration of the Lungs Flint on Respiratory Organs Flint on the Heart ♦Flint's Clinical Medicine Flint's Essays . . . ♦Flint's Practice of Medicine Folsom's Daws of U. Si on Custody of Insane Foster's Physiology . . ♦Fothergill's Handbook of Treatment . Fownes' Elementary Chemistry Fox on Diseases of the Skin . Franklanil and Japp's Inorganic Chemistry Fuller on the Lungs and Air Passages . Gallowaj 'a Analysis .... Gibney's Orthopaedic Surgery Gibson's sin l .... Gluge's Pathological Histology, by Leidy Gould's Surgical Diagnosis . •Gray's Anatomy ... . . Greene's Medical Chemistry . Green's Pathology and Morbid Anatomy Griilith's Universal Formulary Gross 'iii Foreign Bodies in Air-Passages II i- and Sterility . Gross on Urinary Organs •Gross' System ofSurgery Habershon on the Abdomen •Hamilton on Fractures and Dislocations Hamilton on Nervous Diseases Hartahorne's Anat y and Physiology . Ha it si i nine's Conspectus of the Med. Sciences Hartshorne's Essentials of Medicine Hermann's Experimental Pharmacology Hill "I, Syphilis ..... Hillier's Handbook of Skin Diseases Hoblyn's Medical Dictionary Hodge on Women .... Hodge's obstetrics .... 6 Hoffmann and Power's Chemical Analysis :; Holden's Landmarks .... 27 Holland's Medical Notes and Reflections 15 Holmes' System of Surgery l'ii Horner's Anatomy and Histology 28 Hudson on Fever ii Hutchinson on Syphilis 21 Hyde on the Diseases of the Skin . 29 Jones (C. Handfield) on Nervous 17 Juler'a < ij ience and Practice 29 Keating nil Infants 27 King's Manual of Obstetrics . 29 Klein's Histology 17 l.andis on Lai 21 La Roche on Pneumonia, Malaria, etc. . 3 7 La Roche on Yellow Fever . '■>. 20 Laiin-i.ee and Moon's I Iphtbalmic Surgery 6 Lawsnn on llie Eye, Orbit and Eyelid 19 Lea's Studies in Church History . 9 Lea's Superstition and Force 9 Lee on syphilis M Lehmann 8 Chemical Physiology . ;;. 16 Leishman's Midwifery ' . . 23 Lucas on Diseases of the Urethra . is Ludlow's Manual of Examinations 1 1 Lyons On Fever ..... n Mi ilc Materia Medica . 3,'Ji Marsh on the Joints 21 May on Diseases of Women . 25 Ml 'ileal News . ... 'JI Meigs on Childbed Fever 8,21 Miller's Practice of Surgery . s Miller's Principles of Surgery s Mitchell's Nervous Diseases'of Women . 23 Morris on Diseases of the Kidneys l-i Morris on Skin Diseases . 17 Neill and Smith's Compendium of Med. Sci. 10 NetUeshipon Diseases of the Eye . 28 Owen on Diseases of Children 6 *Parrish's Practical Pharmacy 10 Parry on Extra-Uterine Pregnancy 5 Parvin's Midwifery .... P' Pavy on Digestion and its Disorders in Pepper's Forensic Medicine . Pepper's Surgical Pathology Pick on Fractures and Dislocations Pirrie's System of Surgery Playl'air on Nerve Prostration and Hysteria •Playfair's Midwifery . . 25 Politzer on the Ear and its Diseases 13 Power's Human Physiology . Rain's Clinical Chemistry ' . 3, ii Ramsbotham on Parturition 7 Remsen's Theoretical Chemistry . 8 i ^Reynolds' System of Medicine 7 Richardson's Preventive Medicine 16 Roberts on Urinary Diseases 7 Roberts' Principles and Practice of Surgery 21 Kobertson's Physiological Physics 25 Rodwell's Dictionary of Science -1 Boss on Nervous Diseases 27 Sargent's Minor and Military Surgery 7 Savage on Insanity, including Hysteria . 28 Schafer's Essentials of Histology, 21 Schafer's Histology 21 Sehreiber on Massage . 12 Seiler on the Throat, Nose and Naso-Pharynx hi Series of Clinical Manuals 16 Simon's Manual of Chemistry 18 I Skey's Operative Surgery 18 I Slade on Diphtheria .... 18 smith i Edward i on Consumption . 18 Smith (H. H.) and Horner's Anatomical Atlas 18 *Smith tJ. Lewis) on Children lf> I Stllle on Cholera .... 16 *Stille tt Maisch's National Dispensatory 14 *sij He's Therapeutics and Materia Medica 19 Slimson on Fractures .... 8 Stinason's Operative Surgery 16 Stokes on Fever ..... 8 Students' Series of Manuals . 26 Sturges' Clinical Medicine 9 Tanner on Signs and Diseases of Pregnancy Is Tanner's Manual of Clinical Medicine plor on Poisons .... 20 *Tayior's Medical Jurisprudence . 20 Taylor's Pi in. and Prac. of Med. Jurisprudence rhomas on Diseases of Women 3, '20 Thompson on Stricture 5 Thompson on Urinary Organs in Tidy's Legal Medicine. 13 Todd on Acute Diseases 11 Treves' Applied Anatomy 18 Treves on Intestinal Obstruction . 25 Tukenn the Influence of Mind on the Body 21 Walshe on the Heart .... 20 Watson's Practice of Physic . 17 *\\'i-Us on i in- Eye .' . 23 West on Diseases of Childhood pi Weston Diseases of Women ii Wesl on Nervous Disorders in Childhood :; Williams on Consumption l-i Wilsons Handbook of Cutaneous Medicine n Wilson's Human Anatomy . 25 Winckel on Pathol, and Treatment of Childbed 26 Wfthler's Organic Chemistry •) Woodbead's Practical Pathology . 28 Year-Book of Treatment 28 Books marked * are also bound in half Russia. 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