BILE. 407 



The liver is suppliecLwith blood partly by the hepatic artery 

 and partly by the vena portce, which enters the liver at the great 

 fossa, and brings to it the venous blood sent back by the princi- 

 pal abdominal viscera. The vena portce after entering the liver 

 subdivides into numerous branches like an artery, and there can 

 be little doubt that the blood which it supplies is employed in 

 the formation of bile, while the use of the blood which is sup- 

 plied by the hepatic artery is to nourish the liver. That the liver 

 is composed of globules like the other conglobate glands was first 

 pointed out by Malpighi. The best account of the structure of 

 this viscus has been given by Mr Kiernan.* 



The hepatic ducts can be traced along the canals in the fissures 

 between the lobules and into the lobules where they form 

 plexuses. The branches of the portal vein and the hepatic arte- 

 ries also enter the lobules. The venous branches forming a plexus 

 which communicates with the incipient radicles of the hepatic 

 vein, and the arteries, which are very few and minute, are the 

 nutrient vessels of the lobules. The branches of the artery ra- 

 mify freely upon the coats of the portal vein and on the hepatic 

 ducts, furnish materials for the nutrition of both, and to the lat- 

 ter for the secretion of mucus, which lubricates their interior 

 coat. 



Each lobule of the liver is found to consist of a reticulated 

 plexus formed by the minute radicles of the biliary ducts. For 

 these, when examined with a highly magnifying power, are seen 

 to divide and subdivide so as to form a mesh in its interior, which 

 is supported by a cellular tissue, furnished by Glisson's capsule. 

 Upon this mesh is disposed another formed by the terminal 

 branches of the vena portce. It is difficult to inject the ducts, 

 owing to their being filled with bile. Mr Kiernan succeeded by 

 first tying the portal vein and hepatic artery in a living animal 

 after feeding it. Thus the secretion of bile was suspended, and 

 that which the ducts contained discharged. The ducts cannot 

 be injected directly from the hepatic vein ; for no branches from 

 this vessel ramify on their coats. The residue of the blood con- 

 veyed by the hepatic artery to the lobules, to the different ves- 

 sels and to the ducts for their nutrition, is taken up by the mi- 

 nute veins, and conveyed to the vena portce ; so that part of the 

 blood from which bile is secreted is derived from the liver itself, f 



Phil. Trans. 1833, p. 711. 



t See Quain's Anatomy, p. 650, and Kiernan's paper, as quoted above. 



