CHAPTER XI. 

 THE LIVER. 



That portion of the liver which is exposed in the abdominal 

 cavity is covered by a reflection of the peritoneum, closely attached 

 to the organ, because its deeper side is continuous with the fibrous 

 structures or interstitial tissue of the liver itself. This serous cover- 

 ing is so thin that the substance of the liver can be readily seen 

 through it. 



At the portal fissure, the serous coat having been reflected from 

 it, the liver is covered with a loose areolar tissue in which the main 

 trunks of all but one of the vessels connected with it are situated : 

 namely, the portal vein, hepatic artery, gall-duct, and lymphatics. 

 These vessels enter the liver together at this place, and are closely 

 associated with each other in all their ramifications, being supported 

 throughout by areolar tissue, which is continuous with that at the 

 portal fissure and with the interstitial tissue of the liver. 



These vessels, with their supporting fibrous investment, called 

 Glisson's capsule, ramify in the liver in such a way as to resemble 

 a tree with a multitude of branches and twigs, each composed of 

 divisions of all the vessels named. 



The hepatic vein enters the liver at a different place, and also 

 suffers a tree-like subdivision; but its branches are surrounded by a 

 very much smaller amount of fibrous tissue, which may be regarded 

 as but a slightly reinforced portion of the interstitial tissue of the 

 organ. 



Sections of the liver (Fig. 133) will reveal portions of these two 

 trees, cut in various directions with respect to their axes. It will 

 be observed that tin 1 twigs and larger branches of the trees are 

 nowhere in close relations to each other, showing that the hepatic 

 vein, in all its ramifications, is separated from the other vessels by 

 the parenchyma of the organ. If we select some part of a section 

 which contains one of the smallest branches of the hepatic vein, and 

 cut across its axis so that its lumen appears round, we shall notice 

 that at about equal distance- from it there are sections of two, 



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