PANCREATIC JUICE. 249 



opening, the same voracity and emaciation are observed ; and yet there is no 

 single alimentary substance upon which the bile, of itself, can be shown to 

 exert a very decided digestive action. Farthermore, the pancreatic juice is 

 evidently adapted to act upon alimentary matters after they have been sub- 

 jected to the action of the stomach, a preparation which is essential to proper 

 intestinal digestion ; and once passed into the intestine, the food comes in 

 contact with a mixture of pancreatic juice, intestinal juice and bile. It 

 remains to study, therefore, the special action of the pancreatic secretion 

 upon the albuminoids, as far as this influence can be isolated, and its action 

 in conjunction with the other intestinal fluids and in the presence of other 

 alimentary matters in process of digestion. Nitrogenized alimentary sub- 

 stances, when exposed to the action of the pancreatic juice out of the body, 

 become rapidly softened and dissolved in some of their parts, but soon un- 

 dergo putrefaction (Bernard). Analogous changes take place in starchy and 

 fatty matters when they are exposed to the action of the pancreatic juice out 

 of the body, and they pass through the various stages of transformation re- 

 spectively into lactic acid and the fatty acids. Putrefactive action, however, 

 does not readily take place in albuminoids which have been precipitated after 

 having been cooked or in raw gluten or caseine. The presence of fat also 

 interferes with putrefaction ; so that Bernard concluded that the fats have 

 an important influence in the intestinal digestion of nitrogenized substances. 

 Experiments made since the observations of Bernard have shown that the 

 ferment of the pancreatic juice concerned in the digestion of albuminoids is 

 trypsine. 



Trypsine, in an alkaline medium, changes the albuminoids into their 

 respective peptones, in much the same way and involving nearly the same 

 intermediate conditions as in the digestion of these substances by the gastric 

 juice ; but if the action be prolonged, out of the body, the changes continue, 

 and substances are formed which yield leucine, tyrosine and other analogous 

 products. The final putrefactive changes, which result in indol, skatol, 

 phenol etc., some of which have a distinctly faecal odor, are probably due to 

 the influence of micro-organisms. 



Taking into consideration what has been ascertained concerning the 

 action of the pancreatic juice upon the albuminoids, there can be no doubt 

 with regard to the importance of its office in the digestion of these sub- 

 stances after they have been exposed to the action of the gastric juice. Ex- 

 periments upon the digestion of the albuminoids, after they have passed out 

 of the stomach, show that they undergo important and essential changes as 

 they pass down the intestinal canal. While the bile and the intestinal juice 

 are by no means inert, they seem to be only auxiliary in their action to the 

 pancreatic juice. 



The preparation which the albuminoids undergo in the stomach is un- 

 doubtedly necessary to the easy digestion, in the small intestine, of that por- 

 tion which is not dissolved by the gastric juice. This fact has been shown 

 by experiments on intestinal digestion in the inferior animals and by the 

 observations of Busch in the case of intestinal fistula in the human subject. 



