FUNCTIONS OF THE BILE. 183 



tioii,or, as it might be equally well called, excretion, to be forced 

 into the circulating blood instead of into the gall passages. Under 

 normal circumstances, the large receptable of the gall bladder 

 being always ready to receive the bile insures its easy exit from 

 the ducts, but the forces which cause its flow are extremely weak. 



The smooth muscle in the walls of the duct seems rather for 

 the purpose of regulating than aiding the flow. 



When food from the stomach begins to flow into the duodenum, 

 the muscular coat of the gall bladder contracts and sends a flow 

 of bile into the intestine, which action is doubtless brought about 

 by a reflex nerve impulse, for it is only when this part is stim- 

 ulated that the bile flows freely from the bladder, and the acid 

 gastric contents seem to be the most efficacious stimulus. 



In the human subject the quantity of bile secreted has been 

 found to be about 600 cc. (21 oz.) per diem in cases where there 

 were biliary fistulse. This would equal about 13 grms. per kilo, 

 of the body weight. 



In the guinea pig and rabbit it haa been estimated to be about 

 150 grms. per kilo, body weight. 



FUNCTIONS OF THE BILE. 



1. By Neutralizing Acidity and Precipitating Peptones. When 

 the acid contents of the stomach are poured into the duodenum 

 and meet with a gush of alkaline bile, a copious, cheesy precipi- 

 tate is formed, which clings to the wall of the intestine. This 

 precipitate consists partly of acid albumin (parapeptone) and 

 peptones thrown down by the strong solution of bile salts, and 

 partly of bile acids, the salts of which have been decomposed by 

 the hydrochloric acid of the gastric juice. With the bile acids 

 the pepsin is mechanically carried down. Thus, immediately on 

 their entrance into the duodenum, the peptic digestion of the 

 gastric contents is suddenly stopped not only by the precipitation 

 of the soluble peptones and the shrinking of the swollen para- 

 peptone, but also by the removal of the pepsin itself from the fluid 

 and the neutralization of the gastric fluid by the alkaline bile. 



By thus checking the action of the gastric ferment, the bile 

 prepares the chyme for the action of the pancreatic juice. 



