ACTION OF THE ENZYMES. 139 



cause which led to the injury of the cells of the mucous 

 membrane, which, with their consequent inadequate supply 

 of antiproteinase, were digested by the proteolytic ferments 

 present in the alimentary tract. 



In cases of round ulcer of the stomach yet another factor 

 besides lack of antiproteinase plays a role in the production 

 of the lesion, namely, a hyperacidity of the gastric juice. 

 While this hyperacidity has by several authors been looked 

 upon as being involved in the etiology" of round ulcer, just 

 how it was involved could not be said. The experiments of 

 WEINLAND give us a clue. While antiproteinase is able to 

 protect fibrin against digestion by a pepsin-hydrochloric 

 acid mixture, it is able to do so only within certain limits 

 of concentration of the hydrochloric acid. When the conr 

 centration of the hydrochloric acid exceeds a certain point 

 the antiproteinase is only partially able to inhibit the action 

 of the acid-proteinase, so that the fibrin slowly goes into 

 solution. We can imagine the hyperacidity of patients 

 affected with round ulcer to play a similar role, in that the 

 excessive acid present prevents the antiproteinase from 

 adequately protecting the stomach-wall. But the hyper- 

 acidity can by no means be considered even the chief etio- 

 logical factor, for if it were, gastric ulcers should be diffuse 

 affairs, while they are instead more or less localized and 

 often intimately connected with local vascular disturbances. 



The resistance which the submucous tissues of the alimen- 

 tary tract (such as the musculature) usually offer to the 

 digestive fluids that bathe them must also be attributed to 

 the presence of antiproteinase in them. In harmony with 

 this idea we must also assume that when the ulceration of 

 the alimentary tract extends beyond the mucosa the involved 

 tissues have first been rendered susceptible by causes which 

 lead to the presence of an inadequate supply of the anti- 

 ferment. 



The parallelism which exists between the proteinases and 

 antiproteinases on the one hand, and the toxins and antitoxins 



