RESISTANCE OF STOMACH TO AUTODIGESTION 23 



chloric acid. Grlassner 62 has succeeded in separating pro- 

 pepsin from labproferment by precipitation with uranyl 

 acetate. 



Pseudopepsin. The existence of a pseudopepsin, ob- 

 tained from the pyloric mucous membrane by the investi- 

 gator mentioned, said to act under weakly alkaline reaction 

 and to split protein with production of tryptophane, is a 

 matter of considerable doubt; as in the first place it can 

 scarcely be distinguished from autolytic tissue enzymes and, 

 as is well known, the entrance of trypsin into the pylorus is 

 not an infrequent occurrence. 63 



Passage of Pepsin into the Intestinal Canal. Abder- 

 halden has made interesting observations showing the 

 marked readiness with which pepsin is taken up by 

 elastin and similar substances. The pepsin may be practi- 

 cally all removed from the gastric juice by means of elastin. 

 Protected within such albuminoids the enzyme may be car- 

 ried into the intestine and there complete its action. Con- 

 siderable amounts of active pepsin have been detected in the 

 upper portion of the intestine by the elastin method; and 

 apparently peptic digestion is not limited entirely to the 

 stomach, but plays an important role in the intestine as 

 well. 64 



Resistance of Stomach to Auto digestion. The physi- 

 ology of gastric digestion includes another problem which 

 has long stimulated investigation in a marked degree. 

 This concerns the method of protection of the digestive 

 organs against self-digestion. Every thoughtful person 

 who has ever noticed the rapidity with which a bit of albumin 

 is digested by active gastric juice, has necessarily asked him- 



63 K. Glassner, Hofmeister's Beitr., 1, 24, 1901. 



61 Cf . the publications of F. Klug, A. Scheunert and Grimmer, Pekelharing 

 (cited in Handb. d. Biochem., 1, 551, 1909) and F. Reach (Hofmeister's Beitr., 

 4, 143, 1903). 



M E. Abderhalden in association with F. W. Strauch, F. Wachsmuth, 0. 

 Meyer and K. Kiesewetter, Zeitschr. f. physiol. Chem., 71, 314, 339, 1911; 74, 

 67, 411, 1911. 



