THB DISEASES OF CATTLE. 281 



origin, collecting the blood from the capillary network. It 

 then unites with other radicles to form the main trunk, by 

 which it is delivered into the vena cava (see heart and its 

 functions). 



The branches of the hepatic artery are principally distrib- 

 uted upon the walls of the hepatic ducts, and upon the trunks 

 and branches of the portal and hepatic veins, supplying these 

 and the contiguous parts with the necessary amount of arterial 

 blood for their nourishment, as well as that of the whole gland. 



The investing membrane of the liver, from which prolonga- 

 tions extend into its substance, is termed Glisson's capsule. 



The liver derives its nerves and nervo-vital power, from the 

 great sympathetic and eighth pair. 



The liver is confined to its situation by ligaments, which get 

 the name of broad, lateral, coronary, and round. The round 

 ligament is the remains of the umbilical vein of the foetus. 

 The others are continuations or duplicatures of the peritoneum. 



SECRETION OF BILE, ITS USES, ETC. 



The bile is secreted from the capillaries of the hepatic ar- 

 tery, by minute glands found on the surface of the biliary ducts. 

 It then passes through the biliary pores and branches of the 

 hepatic duct. By this duct it is conveyed to the ductus com- 

 munis choledochus,* from whence, in part, it passes by. the cystic 

 duct to the gall bladder. When needed in the duodenum, it re- 

 turns by the cystic duct, and mixes in the ductus communis 

 choledochus with fresh bile from the hepatic duct, and then 

 passes into the duodenum. The bile having entered the in- 

 testine mixes with the aliment and pancreatic juice. The 

 pancreatic juice changes the digested aliment into a brown 

 mass, termed chyme, and then emulsifies it. After being emul- 

 sified, a portion of the chyle is taken up by the lacteals and 

 enters the receptaculum chyli. 



In a healthy state of the system, should any bile escape with 



* Union of the cystic and hepatic ducts. 

 24* 



