ACTION OF THE BILE IN DIGESTION. 251 



quoted by Bernard and others, and they confirm the observations and experi- 

 ments made upon the lower animals. They all seem to show that the action 

 of the pancreas in digestion is essential to life, but that one of the chief 

 disorders incident to the destruction of this gland relates to the digestion of 

 fats. 



Taking into consideration all the facts bearing upon this subject, it is 

 evident that the chief agent in the digestion of fats is the pancreatic juice ; 

 and that this fluid acts by forming with the fat a very fine emulsion, thus 

 reducing it to a condition in which it can be absorbed. How far the bile may 

 assist in this process, is a question which will come up for consideration farther 

 on ; but the facts with regard to the pancreatic juice are conclusive. 



ACTION OF THE BILE IN DIGESTION. 



The physiological anatomy of the liver and the general properties and 

 composition of the bile will be fully considered in connection with the 



FIG. 77. Dog with a biliary fistula. 



From a rousrh sketch made the fourteenth day after the operation. A small glass vessel is tied around 

 the body to collect the bile, and a wire muzzle, the lower part of which is covered with oil-silk, is 

 placed over the mouth to prevent the animal from licking the bile. The dog is considerably 

 emaciated. 



physiology of secretion and excretion ; and here it will be necessary only to 

 study the action of the bile in digestion. 



The question whether the bile be a purely excrementilious fluid or one 

 concerned in digestion was formerly the subject of much discussion ; but it 

 is now admitted by all physiologists that the action of the bile in digestion 

 and absorption, whatever the office of the bile may be as an excretion, is 

 essential to life. The experiments of Swann, Nasse, Bidder and Schmidt, 

 Bernard and others, who have discharged all the bile by a fistula into the 

 gall-bladder, communication between the bile-duct and the duodenum having 

 been cut off, show that dogs operated on in this way have a voracious appetite 



