THE LIVER. 



155 



three, or four twigs of the compound tree. In these the gall-duct 

 can be identified by its distinct lining of columnar or cubical epi- 

 thelium, and the hepatic artery distinguished from the portal vein 

 by its relatively thick wall as compared with the size of its lumen. 

 These vessels are collectively known as the interlobular vessels. 

 Between and around them is the areolar fibrous tissue, which forms 

 a part of Glisson's capsule, and which is abundantly supplied with 



Fig. 133. 



Diagrammatic sketch of a section of liver: a, central vein (radicle of the hepatic vein) ; 6, b, 

 branches of the portal vein ; c, c, branches of the hepatic artery ; d, d, small bile-ducts ; 

 e, lymphatic vessel; b, c, d, e are enclosed in areolar tissue, which is continuous with 

 Glisson's capsule; /, liver-cells; g, line indicating the junction and blending] of two 

 neighboring lobules. 



lymphatic spaces and vessels in the fibrous tissue. The lymphatics 

 appear as clear spaces with smooth walls, some of them with dis- 

 tinct endothelial linings, but almost devoid of any other wall. 



The parenchyma may be subdivided into portions which surround 

 the smallest branches of the hepatic vein, and are bounded by 

 imaginary lines connecting the groups of interlobular vessels. 

 These subdivisions are called " lobules " of the liver. In the 

 human liver they blend at their peripheries, between the masses of 

 connective tissue enclosing the interlobular vessel; but in the liver 

 of the pig these lobules are veritable subdivisions of the liver, and 



