322 



THE LIVES 



clothed with peritoneal epithelium. From this connective tissue 

 capsule, fibrous bands or septa are continued into the substance of 

 the organ and permeate to all its portions. These processes of 

 connective tissue, collectively forming the capsule of Glisson, are 

 most abundant at the transverse fissure, where they contain the 

 large blood vessels and hepatic ducts, this fissure serving as a hilum 

 for the organ. 



The liver is dependent for its structural peculiarities upon the 

 peculiar disposition of the connective tissue of Glisson's capsule, 

 as also of the blood vessels whose branches it contains, for by these 

 tissues the substance of the liver is extensively subdivided into 

 minute collections of hepatic cells, each group forming an ana- 

 tomical unit, the hepatic lobule, which in addition to the hepatic 

 cells contains a connective tissue reticulum and the smaller blood 

 vessels and secretory capillaries (bile canaliculi). The hepatic 

 lobules are analogous to the lobules of compound tubulo-acinar 

 glands, inasmuch as they contain the secreting parenchyma of the 

 organ, but are very different from the latter in the arrangement 

 of the secreting cells which, in the human liver, do not present 

 either a tubular or acinar structure, but form more solid cell col- 

 umns. Thus in the human 

 d liver the tubular character 



of the gland is scarcely ap- 

 parent, yet in the liver of 

 many of the lower animals, 

 notably in that of the turtle 

 and frog, the cells form 

 typical tubules within the 

 indistinct hepatic lobules. 



The bile formed by the 

 liver cells is conveyed to the 

 duodenum by an excretory 

 system, beginning with in- 

 numerable interlobular bile 

 ducts which receive the in- 

 tralobular secretory capil- 

 laries, and, leaving the lobule 

 from all its sides, find their 

 way through the interlobu- 

 lar connective tissue of the capsule of Glisson, unite with their 

 fellows to form larger and larger bile ducts, and finally leave the 



FIG. 265. FROM A SECTION OF THE TURTLE'S 

 LIVER, SHOWING THE TUBULAR ARRANGE- 

 MENT OF THE PARENCHYMA. 

 a, blood capillary, partially filled with clotted 

 blood ; ft, vascular endothelium ; c, darkened 

 central portions of the hepatic cells ; d, periph- 

 eral portion of the hepatic cells. Osmium 

 tetroxid; carmin. x 400. (After Shore and 

 Jones.) 



