Fig. 24.-Transverse section of portions of three lobules of the horse's liver. a. Branch of the hepatic or intralobular vein. b. Interlobular fissure. The radiating lines of cells are very clearly shown in the specimen from which the drawing was taken. They are connected together here and there by narrow oblique or transverse lines. Near the interlobular fissures the cells cease, but with care, the tubes may still be traced for some distance in the fissure, as faint lines. Magnified about 35 diameters. Fig. 25.-Vasa aberrantia from the transverse fissure of the human liver, injected with Prussian blue. The large pale vessels are branches of the portal vein, which are seen to communicate with each other by means of transverse branches. The sacculated ducts are seen running between two branches of the vein. The dark vessel is a branch of the artery which was injected with vermilion, accompanied by two branches of the vein, injected with white lead. In the coats of the gall bladder, in the transverse fissure, and in the larger portal canals, the disposition of the vessels is very similar, each small branch of the artery being accompanied by two branches of the vein. The numerous sacculi are remarkable, and the appearance of this preparation by reflected light is very beautiful. The very dark appearance of some of the cœcal pouches, is caused by their being completely filled with injection. Magnified 25 diameters. Fig. 26.-Branches of duct from the pig's liver, showing the parietal sacculi arranged all round the duct, and fully injected with vermilion. The coats of the duct are not represented. a. Small interlobular duct, the coats of which are very thin and do not contain cavities in their walls. b. Two very large branched sacculi. Fig. 27.-Termination of a small interlobular duct in the pig's liver. The smallest branches, which are not more than 1-3000th of an inch in diameter, are seen to dilate into much wider tubes in which the liver cells lie. The portion of the cell-containing network, seen distinctly in the preparation, is only represented in the figure, but its further extension is shown by dotted lines. The shading marks the points to which the Prussian blue injection had reached. In many places it was observed amongst the cells. The liver, from which this preparation was taken, was very fatty. If this had not been the case, that part of the network represented in this figure would not have been found filled with cells, but would consist only of a network of narrow ducts. a. A portion of the cell-containing network, into which the injection has passed. The cells are seen to be slightly separated from each other, and are nearly surrounded by the injection. b. A few cells within a portion of the tubular membrane, showing the irregularity of their arrangement. They appear to lie free within the tube and not to be adherent to its walls. c. Another portion of the tubular membrane, containing granular matter alone, showing outline of tube, the thickness of which has been much exaggerated in the drawing. These figures have been copied as accurately as possible, and have been photographed from the drawings. Magnified 100 diameters. Fig. 28.-A small portal canal from the liver of the seal. The portal vein and artery have been injected with plain size and the duct with Prussian blue. a. Artery. b. Small branch of the duct, dividing into its terminal branches which are continuous with the tubes of the cell-containing network, situated upon the thin walls of the transparent and distended portal vein. Some of the tubes, containing small liver cells, are represented at c, ramifying upon the coats of the vein, and these have been partially injected. At the lower part of the largest branch of the duct is represented some of the epithelium which lines it, from which the injection has been removed. No fibrous or areolar tissue can be distinguished in this preparation. Magnified 120 diameters. Fig. 29.-A transverse section of a small portal canal from the seal's liver, prepared in the same manner as the last figure. d. A small branch of the portal vein, cut across obliquely. e. Transverse section of the artery. f. Smallest branches of the duct and their termination in the cellcontaining network. g. Branch of the duct, uninjected at this part in consequence of the accumulation of its epithelium. Close to the latter, a divided capillary is represented. The largest duct is divided transversely, just at the point where this branch opens into it. h. A few cells of the epithelial lining of the vein. Many of the small ducts are compressed, and therefore not clearly distinguishable as such in this figure. Fig. 30.-Interlobular duct from the rabbit's liver, injected, and at the same time considerably distended, with Prussian blue. The outline of the portal vein, which is injected with colourless size, is represented by dotted lines. The small trunk of the duct is seen to divide into branches upon the surface of the vein. Many of its small terminal divisions anastomose with each other and form a lax network, which is in direct continuity with that of the lobule. At the lower part of the figure, to the left, a portion of the lobular network is represented. The liver cells were much disintegrated from disease, and for the most part the tubes of the cell-containing network were occupied with granular matter, in which a very few small cells were present. The injection, consequently, penetrated very readily for a considerable distance, into the cell-containing network. Magnified 150 diameters. Fig. 31.-Thin edge of a rabbit's liver about the natural size, to show the manner in which the portal canals and the hepatic venous canals alternate with each other, a point well seen in this liver, as the course of the larger vessels is comparatively straight. The branches of the vein, artery, and duct are somewhat confused in the photograph. Fig. 32.-Tubes of the cell-containing network enormously distended with injection, showing the extent to which this distension may be carried without rupture. Magnified 150 diameters. Fig. 33.-Small ducts from the seal's liver, injected with Prussian blue, showing their continuity with the cell-containing network. A small branch of the portal vein is shown in outline in the upper part of the figure, and in the same situation the continuity of two small ducts with the tubes of the cell-containing network is seen. In the lower part of the figure some of these small ducts may be traced for a short distance into the lobule, before they join, or become continuous with, the tubes of the network. Injected with Prussian blue. Magnified 150 diameters. Fig. 33a.-Liver cells from the rabbit, lying within tube of basement membrane, which has been torn away with them. The walls of the tube shrink very much where they are not kept apart by its contents. Magnified 150 diameters. Fig. 34.-Portion of a small interlobular duct of the lamb, showing the character of its epithelial lining. Some of the liver cells are also represented. cat. Magnified 200 diameters. Fig. 35.-Interlobular duct and artery, from a small portal canal of the Magnified 200 diameters. Fig. 36.-A small branch of the hepatic vein from the seal. The constrictions are produced by a projection, into the interior, of the lining membrane, which is surrounded at certain intervals by a narrow circular band of muscular fibres, lying between the lining membrane and the external coat of the vein. At the lower part of the figure is represented a portion of the cellcontaining network. Magnified 200 diameters. Fig. 37.-Interlobular duct with sacculi from the pig's liver, injected with Prussian blue. The sacculi are arranged entirely round the duct. Their neck is not more than 1-5000th of an inch in diameter. The interrupted lines indicate the fibrous coat of the duct. d. Small artery. Magnified 20 diameters. Fig. 38.-One of the parietal sacculi magnified 110 diameters. The epithelial lining is shown, and has been forced to the lower part of its cavity by the accumulation of the injection. b. Wall of sacculus, extending a little beyond the outer coat of the duct. Fig. 39.-Interlobular ducts with branches to cell-containing network of the lobule, and a few parietal sacculi, from the human foetus about the ninth month. a. Cell-containing network of lobule. branches of the duct as they lie in Injected with Prussian blue. Fig. 40.-A preparation, similar to the last, from the fœtal calf, showing branches of duct passing to the secreting structure and parietal sacculi. Injected with Prussian blue. a. Part of cell-containing network. c. Anastomoses between some of the finest branches of the duct. Fig. 40a.-Interlobular ducts with fine branches to lobule from the human fœtus. a. Anastomoses between finest branches. b. Cell-containing network of lobule. c. Sacculi and branches in the fibrous coats of the duct, opening into its cavity by a row of orifices on each side of the tube. d. Small branch of portal vein, surrounded by a few branches of the duct. Magnified 25 diameters. Fig. 41.-Thin section of a part of the margin of a lobule, with a portion of the interlobular fissure, from the liver of a man forty-three years of age. The liver cells have been rendered indistinct by the action of a weak solution of soda, in which this preparation had been hardened. a. The point where the ductal part of the tube becomes dilated into the secreting portion which contains the liver cells. b. Section of portal capillary. c. Section of small artery. Fig. 42.-A similar specimen from the same liver which has been much flattened in consequence of having been subjected to great pressure between the glasses. e. Epithelium within the finest branches of the duct. Magnified 150 diameters. Fig. 43.-Another preparation from the same liver, showing meshes of cell-containing network. g. Portion of finest duct flattened from pressure. Magnified 150 diameters. Fig. 44. Capillaries of lobule, d, with tube of cell-containing network between them, from the human liver. Magnified 300 diameters. Fig. 45.-Portion of cell-containing network of lobules of human liver, very much stretched. ƒh. Capillaries very faintly represented. Magnified 300 diameters. Fig. 46.-A small duct at the point where it becomes continuous with the cell-containing network, from the human liver. The cells are much altered from the mode of preparing the specimen, and the duct is much distended with injection. Magnified about 110 diameters. Fig. 47.-Small portion of the capsule of a lobule of the pig's liver, showing the delicate fibrous tissue of which it consists. Fig. 48.-An interlobular duct from the pig's liver dividing into smaller branches upon the surface of a lobule. Injected with Prussian blue. The injection has entered the superficial portion of the cell-containing network, producing the mottled appearance represented. Magnified 20 diameters. Fig. 49.-Portion of the network of a lobule of the pig's liver much shrunken, and not containing liver cells, an appearance produced in preparing the specimen. Magnified 110 diameters. Fig. 50.-Branches of tubes of cell-containing network of the pig's liver. Magnified 110 diameters. Fig. 51.-A part of the most superficial portion of the tubular network of the lobule of the pig's liver. These tubes lie partly in the fibrous capsule itself, and partly within the capsule. The tubes contain a few small cells, free oil globules, and granular matter. Partially injected. Magnified 110 diameters. Fig. 52.-Portion of cell-containing network from within the lobule of the pig's liver. - Partially injected with Prussian blue. Magnified 110 diameters. Fig. 53.-A small portion of the network represented in fig. 51, distended with injection. Fig. 54.-Small branches of the portal vein with capillary network partly injected with vermilion. From the eel's liver. Magnified 110 diameters. Fig. 55.-Portion of the cell-containing network from the liver of another eel which had been kept without food for some time. The oil globules are |