AUTODIGESTION 25 



think that the prevention of the action of a gastric juice after 

 addition of gastric epithelial cells is due solely to " anti- 

 pepsin. ' ' 70 



The following experiment by E. S. May in the laboratory 

 of Eene du Bois-Reymond 71 is instructive. The serosa and 

 mucosa of a dog's stomach were separately prepared and 

 spread out over glass plates, and placed in gastric juice. 

 After eighteen hours the mucosa was not changed ; but the 

 serosa was markedly acted upon, at one place with complete 

 penetration. 



The question has been approached from another stand- 

 point, too, by introducing living tissue into the opened 

 stomach of an animal. Although these experiments have 

 not been productive of uniform results (a living spleen with 

 its blood vessels attached has been digested quite rapidly), 

 we must accept the fact that, for example, the foot of a live 

 frog introduced into the stomach of another frog, or perhaps 

 a loop of living intestine placed into an incised stomach, may 

 remain intact for many hours. 72 On the other hand, very 

 active solutions of trypsin have been known to digest living 

 tissue (tails of rats and mice). 73 



In conclusion mention may be made of such observations 

 as those of Claudio Fermi showing that many aquatic ani- 

 mals (protozoa, worms, crustaceans, insects) may live with- 

 out the least harm in trypsin-solutions. 74 A solution 

 of trypsin, capable of rapidly digesting a large lump of 

 coagulated albumin, has been found to be without any effect 

 upon the tiny mass of protoplasm of an infusorian, unpro- 



70 R. duBois-Reymond, Berl. physiol. Ges., July 21, 1911, Centralbl. f. 

 Physiol., 25, 774, 1911. 



11 1. c. 



"Neumann, Centralbl. f. allg. Pathol., 18, 1, 1907; Kathe, Berliner klin. 

 Wochenschr., 1908, 2135; Katzenstein, ibid., 1749; G. Hotz, Mitt. a. d. 

 Grenzgebieten d. Med. u. Chir., 21, 143, 1909 ; R. du Bois-Reymond, 1. c. 



71 L. Kirchheim (Labor. M. Cremer, Cologne), Arch. f. exper. Pathol., 26, 

 352, 1911. 



T4 C1. Fermi, 1. c. 



