622 



OF SECRETION. 



by the convergence of the veins, which return the blood from the chylopoietic viscera ; and 

 there is reason to believe that it also receives the blood, which is conveyed to the Liver for 



Fig. 229. 



Connection of the lobules of the liver with 

 the hepatic vein; 1, a trunk of the vein; 2, 2, 

 lobules depending from its branches, like 

 leaves on a tree; the centre of each being 

 occupied by a venous twig, the Intra-lobu- 

 lar Vein. 



Horizontal section of three superficial lobule?, 

 showing the two principal systems of Blood-Ves- 

 sels ; 1, 1, inra-lobular veins, proceeding from the 

 Hepatic veins; 2, 2, inter-lobular plexus, formed 

 by branches of the Portal veins. 



Fig. 231. 



the purposes of Nutrition, by the Hepatic Artery. As it is an afferent, not an efferent ves- 

 sel, it has a strong claim to the character of an Artery; even although it conveys Venous 

 blood. Like an artery, it gradually subdivides into smaller and yet smaller branches; and 

 at last forms a plexus of vessels, which lie in the inter-lobular spaces, and spread with the 

 freest inosculation, throughout the entire Liver. To these vessels, the name of infcr-lobular 

 Veins is given by Mr. Kieruan. They ramify in the capsules of the lobules, covering with 

 their ramifications the whole external surface of these ; and then enter their substance. 

 When they enter the Lobules, they are termed lobular veins ; and the plexus formed by their 

 convergence, from the circumference of each lobule towards its centre (where their ultimate 

 ramifications terminate in those of the intra-lobular or hepatic vein), is designated as the 

 Lobular Venous plexus. In the islets of this plexus (the acini of Malpighi) the ramifications 

 of the hepatic duct are distributed in the manner next to be described. 



c. The Hepatic duct forms, by its subdivision and ramification, an Interlobular plexus of a 

 very similar character; but the anastomosis between the branches going to the different lobules 



is less intimate than that of the inter- 

 lobular veins, and cannot be directly 

 demonstrated ; although Mr. Kiernan 

 thinks that his experiments leave but 

 little doubt of its existence, a com- 

 munication (which cannot be seen to be 

 established by any nearer channel) be- 

 ing proved to exist between the right 

 and left primary subdivisions of the 

 duct. The Intorlobular Ducts ramify 

 upon the capsular surface of the lobules, 

 with the branches of the Portal Vein 

 and Hepatic Artery ; they then enter its 

 substance, and subdivide into minute 

 branches, which anastomose with each 

 other, and form a reticulated plexus, 

 Horizontal section of two superficial Lobules, show- termed by Mr. K., the Lobular Biliary 

 ing the interlobular plexus of biliary ducts; 1, 1, intra- plexus. This plexus constitutes the prin- 

 lobular veins ; 2, 2, trunks of biliary ducts, proceeding c ij m l part of the substance of the lobule ; 

 from the plexus which traverses the lobules ; 3, inter- and when seen through the meshes of 

 lobular tissue ; 4, parenchyma of the lobules. the Portal plexus, gives rise to the ap- 



