The Liver and Pane in is. 103 



by warming. This test is not solely indicative of bile acids ; 

 other substances also give it. 



The origin of the bile acids is wrapped in obscurity; 

 taurin is formed in the body, probably also glycin, and 

 cholalic acid is formed in the liver. Beyond this we know 

 but little, not even why glycin should predominate in some 

 animals and taurin in others. 



Bile is secreted under a very low pressure, which is the 

 reverse of what occurs in the saliva ; but low as the pres- 

 sure is (-58 inch of mercury), it is higher than that of the 

 blood in the portal vein — in fact double. The secretion of 

 bile is a continuous one ; whether the horse be in full diges- 

 tion or fasting the flow does not intermit like the saliva. 

 During digestion the amount of bile increases. 



Quantity of Bile. — The amount secreted varies, but is 

 greater in herbivora than carnivora. Colin's experiments 

 gave him the following amounts as hourly secretions : 



Ox - " 3tt ozs. to 4|- ozs. per hour. 



Sheep - j oz. to bh ozs. „ ,, 



Horse - 8=^ ozs. to HH ozs. ,, ., 



In those animals possessing a gall-bladder this receptacle 

 is filled during abstinence, or, if it be empty, it is filled 

 even during digestion. It empties itself through its own 

 contractions. 



The nervous influence controlling the secretion of bile is 

 unknown. 



The Use of the Bile from a digestive point of view is very 

 disappointing, inasmuch as it does not digest in the sense 

 that pepsin and trypsin do. That it is intimately connected 

 with that of the pancreas would appear to be the case, from 

 the fact that the secretions are poured out either close 

 together in the bowel, or, as in the horse, by a duct common 

 to the two glands. As the horse possesses no gall-bladder, 

 the secretion as fast as it is prepared is poured into the 

 intestine ; not so with the ox, where it is stored up in a 

 capacious gall-bladder until required. From what has 

 been previously said, we can see the reason of this remark- 



11—2 



