VASCULAR SYSTEM. 137 



v?. Experiment proves that it does not. 



Q. What are the evidences that bile is exclusively 

 formed by the vena portal blood ? 



A. This remains but a plausible hypothesis; there is 

 no positive proof of the fact. Bichat thinks that both the 

 vena portal blood and that of the hepatic artery concur to 

 form the bile. 



Q. Does the blood of the venaportarum differ from the 

 black blood in the general system? 



#. It has been so supposed, but the reasons are exceed- 

 ingly doubtful in their character. 



Q. Does the slow motion of the blood in the vena por- 

 tarum favour the biliary secretion? 



. As this sluggish circulation does not appear in other 

 organs, there is no reason to believe it necessary or con- 

 ducive to the hepatic secretion. 



Q. What proof is there that the spleen does not send 

 matter essential to the formation of bile? 



.#. Because, where the spleen is wanting, or removed, 

 bile has been formed in the usual manner. 



Q. Is the flow of bile into the duodenum constant? 



A. The hepatic flows constantly; the cystic only during 

 intestinal digestion. 



Q. Does Bichat suppose that bile exists in the stomach? 



<ft. From experiments made on animals he believes that 

 bile is always in the human stomach; and that it is hepa- 

 tic, not cystic bile, which is found there. 



Q. At what stage of life does the liver receive most 

 blood? 



*ft. In the foetal period. 



Q. What difference does birth make in the circulation 

 of the liver? 



18 



