CH. xxxni.] THE LIVER. 497 



transverse fissure it is merged in the areolar investment called 

 Glisson's capsule, which, surrounding the portal vein, hepatic 

 artery and hepatic duct, accompanies them in their branchings 

 through the substance of the liver. 



Structure. The liver is in origin a tubular gland, but as 

 development progresses it soon loses all resemblance to the 

 tubular glands found elsewhere. It is made up of small roundish 

 or oval portions called lobules, each of which is about -$ of an 

 inch (about i mm.) in diameter, and composed of the liver cells, 

 between which the blood-vessels and bile-vessels ramify. The 

 hepatic cells (fig. 404), which form the glandular or secreting 



Fig. 408. Portion of a lobule of liver, a. bile capillaries between liver-cells, the network 

 in -which in well seen ; b, blood capillaries, x 350. (Klein and Noble Smith.) 



part of the liver, are of a spheroidal form, somewhat polygonal 

 from mutual pressure, about -gfo to 10 1 00 inch (about -^ to 

 ^ mm.) in diameter, possessing a nucleus, sometimes two. The 

 cell-substance, composed of protoplasm, contains numerous fatty 

 particles, as well as a variable amount of glycogen. The cells 

 sometimes exhibit slow amoeboid movements. They are held 

 together by a very delicate sustentacular tissue, continuous with 

 the interlobular connective tissue. 



To understand the distribution of the blood-vessels in the liver, 

 it will be well to trace, first, the two blood-vessels and the duct 

 which enter the organ on the under surface at the transverse 

 fissure, viz., the portal vein, hepatic artery, and hepatic duct. As 

 before remarked, all three run in company, and their appearance 

 on longitudinal section is shown in fig. 405. Running together 



K.I'. K K 



