]68 THE PROCESSES OF DIGESTION AND RESORPTION. 



the presence of the increased amount of pabulum an increase of 

 bacterial fermentation beyond the normal takes place. As a result 

 the various acid decomposition-products of the carbohydrates such 

 as lactic acid, butyric acid, acetic acid, formic acid, succinic acid, 

 together with carbon dioxide, methane, and hydrogen, are formed in 

 increased amounts, and are responsible for the resulting pathological 

 conditions. 



DIGESTION OF THE ALBUMINS. 



The digestion of the albumins takes place in the stomach and 

 in the small intestines under the influence of the pepsin and the hy- 

 drochloric acid of the gastric juice, and the trypsin of the alkaline 

 pancreatic juice, respectively. We know that the presence of the 

 former is not altogether necessary, however, and that the pancreatic 

 juice is in itself quite sufficient to accomplish the digestion of the 

 albumins alone, but under normal conditions the gastric juice also 

 plays a part. Of the relative extent to which the one or the other 

 enters into this process our knowledge is not complete. We may 

 imagine that in the stomach a primary dissolution of the solid con- 

 stituents of the food takes place, and that the soluble products 

 which are thus formed are further digested by the pancreatic juice. 

 This actually occurs to a certain extent, but we further know that 

 in the stomach certain albuminous food-stuffs are decomposed, with 

 the liberation of constituents which are insoluble in the gastric juice, 

 and which pass the pylorus as such and are then modified by the 

 pancreatic juice. Tryptic digestion, moreover, is far more extensive 

 than peptic digestion, so that we may well conclude that the latter 

 essentially represents a preliminary phase of digestion; and that 

 the digestion proper, viz., the transformation of the albumins into 

 those final products which can be directly utilized by the body, 

 occurs under the influence of the trypsin of the pancreatic juice. 



For convenience' sake, we shall study the action of the gastric 

 juice and of the pancreatic juice separately upon the various classes 

 of albumins, as the digestive products which are formed are somewhat 

 different in the different classes. In every case we shall follow the 

 fate of these various substances to the final products, as we obtain 

 them artificially in digestive experiments in vitro ; but we must 

 bear in mind that such experiments cannot reproduce what actually 

 takes place in the living body, where resorption is constantly going 

 on, and where the various digestive processes in a manner supple- 

 ment each other, and conditions overlap. Whenever possible we 

 shall attempt to point out where gastric digestion probably ceases and 

 pancreatic digestion begins, but such an attempt must of necessity be 

 more or less crude. 



Digestion of the Native Albumins. 



Gastric Digestion. In the stomach the native albumins, if in- 

 troduced in the coagulated state, are first transformed into a soluble 



