126 SPECIAL HISTOLOGY. 



§162. 

 Vessels and nerves of the liver. — The arrangement of the 

 blood-vessels in the liver distinguishes it from all other organs, 

 inasmuch as, besides an artery and an efferent vein, it possesses 

 an additional, afferent vein, the vena porta. While the latter 

 is appropriated to the supply of the secreting parenchyma, 

 being directly continuous through the capillary network with 

 the hepatic vein, the artery is more especially distributed to 

 the walls of the biliary ducts and of the portal vein, to 

 Glisson's capsule, and to the serous investment of the liver, 

 taking only a subordinate share in supplying the capillary 

 network of the hepatic islets. The ramifications of the portal 

 vein, and of a few small veins of the stomach and gall 

 bladder (see Weber, Ann. Acad. 1845), which enter the liver 

 independently, take place for the most part dichotomously ; 



is almost obliterated by the close approximation of the nuclei of the opposite walls. 

 These structures now described, I believe to be truly the terminal branches of the 

 hepatic duct, from which they certainly originate. They seem gradually to lay aside 

 the several component tissues of the larger ducts, the fibrous coat blending with the 

 ramifications of Glisson's capsule, the basement membrane imperceptibly ceasing, and 

 the epithelium becoming resolved at last into its simple fundamental nuclei" (1. c, 

 p. 125). 



It is important to remark, that in a Dog, Dr. H. Jones found biliary matter in the 

 interlobular fissures. 



From the fact that in the contents of the hepatic ducts of Man and the Sheep, ex- 

 tracted by means of a forceps and without injuring the organ, hepatic cells may be 

 detected, Mr. Wharton Jones ('Phil. Trans.,' 1848) draws the conclusion that the 

 hepatic cells are endogenous cells, answering to the epithelium of other glands — 

 which was Henle's view. It is impossible to doubt a fact stated by so careful an 

 observer ; but, however these cells may have got into the large biliary ducts, it is 

 quite clear, from a comparison of diameters, that they cannot enter the minutest 

 ones — the total diameter of the latter being the same as that of the cells, viz. -^th 

 of an inch. 



We are strongly inclined to believe that the view taken by Dr. H. Jones is in the 

 main correct — that the liver is essentially of the same order as the " ductless" 

 glands and should be placed in the same category as the Peyerian follicles, spleen p 

 &c. In fact, startling as this view may at first appear, a very clear transition be- 

 tween the Peyerian follicles, &c, and the liver, is afforded by the tonsils ; which, on 

 the one hand, are identical with Peyer's follicles, in so far as they are solid vascular 

 networks, whose meshes are filled by a morphologically indifferent tissue ; while, on 

 the other hand, without differing from the liver in this respect, they resemble it in 

 having these elements arranged around diverticula of the intestinal mucous mem- 

 brane. — Eds.] 



