STRUCT UEE OF THE LIVEE. 



26l 



toward the centre of the cell, and in it is suspended the nucleus. All the hepatic cells are 

 not in the same phase of activity at the same time. Afanassiew finds that if the formation of 

 bile in the liver be increased (e.g., by section of the hepatic nerves, or feeding with proteids), 

 thecells are moderately enlarged in size, and contain numerous granules, which are proteid in 

 their nature ; such cells resist the action of caustic potash. When there is a great formation 

 of glycogen (as after feeding with potatoes and sugar), all the cells are very large and sharply 

 defined, and contain many granules of glycogen, the cells being so large as to compress the 

 capillaries. These cells dissolve quickly in caustic potash. 



Action of Drugs. Some substances excite the cells to activity, and cause them to present the 

 appearance of cells in activity, e.g., pilocarpin, muscarin, aloes, less so salicylate and benzoate 

 of soda and rhubarb, while atropin and lead acetate inhibit the signs of activity. These results 

 were obtained in the horse by Ellenberger and Baum. [Stolnikow, by using the quadruple- 

 staining method of Gaule, finds that the hepatic cells of the frog undergo remarkable changes 

 in poisoning by phosphorus. It is well known that this drug produces fatty degeneration of 

 the liver-cells, but a deeper study shows that the changes are both histological and chemical. 

 Besides producing remarkable changes in the protoplasm of the cell, the protoplasm of the 



N 



Fig. 193. 



Liver-cells of frog, a, early, and b, late stage in poisoning by phosphorus ; c, liver-cell of 



frog getting water only, d, getting sugar, and e, peptone (Stirling after Stolnikow). 



nucleus, in the form of small masses called plasm osoma, passes out into the cell-body, perhaps 

 to renew the latter. The cells are increased in size, both after poisoning with phosphorus and 

 after excision of the fat bodies in the frog (fig. 193). The fat present in the liver in phosphorus- 

 poisoning is not present as droplets of oil, but probably in a loose combination, e.g., lecithin, 

 and as a matter of fact the amount of liver-lecithin is extraordinarily increased. There is also an 

 increase of the nuclein ; while glycogen is absent. The season of the year also affects them. 

 There is a period of growth from July to November, and one of decay from December to May 

 (A. Leonard). Antipyrin also produces profound changes, especially in the nuclei.] 



4. The Bile-Ducts. The finest bile-capillaries, channels, or canaliculi arise from the centre of 

 the lobule, and indeed throughout the whole lobule they form a regular anastomosing network 

 of very fine tubes or channels. Each cell is surrounded by a polygonal usually hexagonal 

 mesh (fig. 194, 3). The bile-capillaries always lie in the middle of the surface between two 

 adjoining cells (II, a), where they form actual intercellular passages (fig. 192). [According 

 to some observers, they are merely excessivety narrow channels (1 to 2 fi wide) in the cement 

 substance between the cells, while according to others they have a distinct delicate wall. The 

 bile-capillary network is much closer than the blood-capillary 

 network. [Thus, there are three networks within each lobule 



(1) A network of blood-capillaries ; 



(2) hepatic cells ; 



(3) ,, bile-capillaries; (fig. 192).] 



Excessively minute intracellular passages are said to pass from 

 the bile -capillaries into the interior of the liver-cells, where they 

 communicate with certain small cavities or vacuoles (Asp, Kupffer) *> Liver-cell during fasting; 

 (fig. 194, 3). As the blood-capillaries run along the edge of the 2 > containing masses of gly- 

 liver-cells, and the bile-capillaries between the opposed surfaces 

 of adjacent cells, the two systems of canals within the lobule are 

 kept separate. Some bile-capillaries run along the edges of the 

 liver-cells in the human liver, especially during embryonic life. 

 Towards the peripheral part of the lobule, the bile-capillaries are 

 larger, while adjoining channels anastomose, and leave the lobule, where they become inter- 

 lobular ducts (g), which, join with other similar ducts to form larger interlobular bile-ducts. 

 These accompany the hepatic artery and pOrtal vein, and leave the liver at the transverse 

 fissure. The finer interlobular ducts frequently anastomose in Glisson's capsule, possess a struc- 

 tureless basement membrane, and are lined by a single layer of low polyhedral epithelial cells. 

 The larger interlobular ducts have a distinct wall, consisting of connective and elastic tissue, 



Fig. 194. 



cogen ; 3, a liver-cell sur- 

 rounded with bile-channels, 

 from which fine twigs pro- 

 ceed into the cell-substance 

 to end in vacuoles. 



