THE LIVER SECRETION OF BILE. 



Fig. 138. 



515 



Fig. 139. 



Connection of the Lobules of the Liver with the Hepatic Vein; 

 1. trunk of the vein; 2, 2, 2, lobules depending from its branches 

 like leaves on a tree, the centre of each being occupied by a 

 venous twig the intralobular vein. (After Kiernan.) 



Glandular Cells of Liver; o, nu- 

 cleus; fc, nucleolus (?) c, adipose 

 particles. 



and to these, if they deserve a name, it ought to be restricted. They will be presently 

 shown, however, lo be nothing else than the irregular islets, left between the meshes of 

 the plexus formed by the ultimate ramifications of the Portal Vein. The Vena Portae, it 

 will be recollected, is formed by the con- 



Fig. 140. 



vergence of the veins, which return the 

 blood from the chylopoietic viscera; and 

 there is reason to believe that it also re- 

 ceives the blood, which is conveyed to the 

 Liver for the purposes of Nutrition by the 

 Hepatic Artery. As it is an afferent, not 

 an efferent vessel, it has a strong claim 

 to the character of an Artery; even al- 

 though 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 trzter-lobular Veins is given by 

 Mr. Kiernan. They ramify in the capsules 

 of the lobules,covering with their ramifica- 

 tions 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 circumfe- 

 rence of each lobule towards its centre 

 (where their ultimate ramifications ter- 

 minate in those of the intra-lobular or he- 

 patic 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 man- 

 ner 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 dif- 

 ferent lobules is less intimate than that of the interlobular veins, and cannot be directly 

 demonstrated; although Mr. Kiernan thinks that his experiments leave but little doubt of 

 its existence, a communication (which cannot be seen to be established by any nearer 

 channel) being proved to exist between the right and left primary subdivisions of the 

 duct. The Interlobular 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 sub- 

 divide into minute branches, which anastomose with each other, and form a reticulated 

 plexus, termed by Mr. K. the Lobular Biliary plexus. This plexus constitutes the princi- 

 pal part of the substance of the lobule ; and when seen through the meshes of the Portal 

 plexus, gives rise to the appearance of coecal terminations of ducts. rnu ~ " u: *~ '"" 



Horizontal section of three superficial Lobules, 

 showing the two principal systems of blood-vessels ; 

 1, 1, inZro-lobular veins, proceeding from the hepatic 

 veins; 2, 2, inter-lobular plexus, formed by branches 

 of the portal veins. (After Kiernan.) 



The ultimate ter- 



