FUNCTIONS OF THE LIVER. 



329 



hepatic artery as "supplying nutrition to the interlobular 

 structures and terminating in the lobular capillary net-work." 

 A noteworthy feature of the capillary net-work envelop- 

 ing the cellular hodies is that each mesh does not merely cover 

 one cell, but several. Indeed, were it otherwise, the bile- 

 capillaries could not exist as individual channels and give an 

 uninterrupted free way to their contents without allowing the 

 bile to penetrate the blood-stream. To prevent this, and yet 

 simultaneously insure perfect exposure to the blood and lymph, 

 a very simple arrangement exists: i.e., three or more of the 





SECTION OF LIVER SHOWING THE LOBULES, CELLS, AND THH 

 BLOOD-SUPPLY. (Piersol.) 



P.V., Portal vein. H.A., Hepatic artery. H.V., Hepatic vein. 



cells (usually polyhedral) are joined longitudinally, and, while 

 the narrow passage in the center of the group thus formed 

 serves as a bile-channel, the outside only is in contact with 

 the blood- and lymph- capillaries. When only two cells are 

 thus joined, the surfaces in contact have in their center a small 

 opening, which, being adjusted to that of the adjoining cell, 

 insures the continuity of the channel. It thus becomes clear 

 that the blood-plasma may penetrate the cell, undergo or in- 

 duce metabolism therein, and the product pass out through 

 the intercellular biliary passages or bile-capillaries. The cells 



