24 GASTRIC DIGESTION OF PROTEINS 



self how it is that the mucosa of the living human and animal 

 stomach is able to withstand the peptic action of the gastric 

 juice. As early as in the eighteenth century Hunter was 

 searching for an answer to this question ; and ever since the 

 great Claude Bernard interested himself in it it has never 

 been dropped from the list of the day's work awaiting the 

 physiologist. 65 



The author has in an earlier volume taken up the discus- 

 sion of anti- ferments (in the first volume of this series, p. 

 559, Chemistry of the Tissues). Following A. Danilewski's 

 demonstration of the existence of an antipepsin in the lining 

 of the stomach and that of Ernst Weinland 66 proving the 

 resistance of parasitic worms to the gastric and intestinal 

 ferments from this standpoint, numerous investigations have 

 been made upon the subject. A diffusible agent has been 

 found in the gastric juice which withstands heating, is re- 

 sistant to acids and alkalies and is capable of inhibiting 

 peptic activity 67 ; but it should be remembered that blood 

 serum freed of diffusible material by dialysis may also show 

 antipeptic activities. 68 0. Schwarz, working in Hofmeister 's 

 laboratory, found after heating pepsin solutions to above 60 

 C. a substance capable of inhibiting peptic activity which 

 apparently had been in the solutions before subjection to 

 heat and which was not formed directly from the pepsin 

 itself. 69 Whether any of these contributions, however, have 

 a physiological bearing seems decidedly questionable. 



For example, knowing that pepsin can be easily separated 

 from a solution by animal charcoal one might hesitate to 



68 Literature upon the protection of the stomach and intestine from auto- 

 digestion: Cl. Fermi (S'assari), Centralbl. f. Bakteriol., 56, 55, 1910, and Arch, 

 di farmacol. sperim., 10, 449, 1911; cf., Centralb. f. d. ges. Biol., 13, No. 369, 

 1912; C. Oppenheimer, Fermente, 3d ed., 270-271, 1910. 



"E. Weinland (Physiol. Inst., Munich), Zeitschr. f. Biol., U, 1, 45, 1902. 



91 L. Blum and E. Fuld, Zeitschr. f . klin. Med., 58, 5-6, 1906. 



M. Jacoby, Biochem. Zeitschr., 2, 247, 1906. 



89 0. Schwarz (Physiol. Chem. Institut., Strassburg), Hofmeister's Beitr., 

 6, 524, 1905. 



