ACTION ON NITROGENIZED PRINCIPLES. 355 



rapid emaciation, with great voracity, and the passage, not 

 only of unchanged fats and starch, but of undigested nitro- 

 genized matter in the dejections. In some instances, pieces 

 of tripe which had been fed to the animal were recognizable 

 in the faeces " by their aspect, because of their slight altera- 

 tion." * The voracious appetite, progressive emaciation, and 

 the passage of all classes of alimentary substances in the 

 fseces, after this operation, demonstrate conclusively the great 

 importance of the pancreatic juice in digestion. But when 

 we inquire into the precise mode of action of this fluid upon 

 the albuminoids, the question becomes one of great difficulty. 

 If the bile be shut off from the intestine and discharged ex- 

 ternally by a fistulous opening, the same voracity and ema- 

 ciation are observed ; and yet there is no single alimentary 

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

 exert a decided digestive action. Furthermore, the pancre- 

 atic juice is evidently calculated to act upon alimentary prin- 

 ciples after they have been subjected to the action of the 

 stomach, a preparation which is absolutely essential to proper 

 intestinal digestion ; and once passed into the intestine, the 

 food comes in contact with a mixture of pancreatic juice, in- 

 testinal juice, and bile. We have to study, therefore, the 

 special action of the pancreatic secretion upon the albumi- 

 noids, as far as it can be isolated, and its action in conjunc- 

 tion with the other intestinal fluids, and in the presence of 

 other alimentary principles in process of digestion. 



The first definite observations upon these points were 

 made by Bernard. He found that the albuminoid substances 

 generally, exposed to the action of the pancreatic juice out 

 of the body, became rapidly softened and dissolved in some 

 of their parts, but soon passed to a condition of putrefaction. 

 An analogous change, it will be remembered, also takes place 

 in starchy and fatty matters when exposed to the action of 

 the pancreatic juice out of the body, and they pass through 

 the various stages of transformation respectively into lactic 



1 BERNARD, Memoir e snr Ic Pancreas, Paris, 1856, p. 137. 



