INTESTINAL CONTENTS AND EXCREMENTS. 121 



lapsed ; and, on opening them, the pieces of flesh and albumen 

 presented a macerated appearance, as if they had been exposed to 

 the action of gastric juice, and were strongly alkaline; the albumen 

 was thoroughly softened and broken down, and in the twelve 

 experiments at present made, lost from one-eleventh to one-half of 

 its original weight, (the experiments including both albumen which 

 had been dried at 120, and moist specimens,) so that in the latter 

 case the contents of the bags appeared to have almost entirely 

 vanished. The experiment succeeded equally well when the gastric 

 juice was excluded, but access of the bile and pancreatic juice was 

 allowed. The cork plug was then, of course, introduced between 

 the pylorus and the openings of the biliary and pancreatic ducts. 



THE CONTENTS OF THE INTESTINAL CANAL AND THE 

 EXCREMENTS. 



The chemical examination of the contents of the intestinal 

 canal has not as yet led to any very certain results ; indeed, up to 

 the most recent time, we find that different opinions are held 

 regarding certain points which might easily be decided. We can 

 readily understand the reason of this, when we consider the great 

 variety of matters which must necessarily occur in the intestinal 

 canal. We need hardly observe, that even after tolerably simple 

 food, imperfectly digested and indigestible substances will be 

 simultaneously found in association with already metamorphosed 

 and decomposed matters, and that to this already very complicated 

 mixture there are added the constituents of the digestive fluids in 

 every stage of metamorphosis. The difficulty of the investigation lies, 

 however, especially in the circumstance that the digested soluble 

 substances always occur in only extremely minute quantity in those 

 parts of the intestinal canal where they are pretty quickly resorbed. 

 The insoluble substances in the intestinal contents are less 

 accessible to chemical examination, and are unquestionably of 

 less interest in relation to the study of the process of digestion. 

 We shall here limit ourselves to a notice of the actual experiments 

 that have been made on this subject, since the metamorphosis of 

 food as a special process will be subsequently considered when we 

 treat of " Digestion." 



In regard to the reaction which the intestinal contents exhibit 

 toward vegetable colours, we may remark, that an acid reaction is 



