FERMENTATION 259 



Cohnheim 1 attempted to find in the intestinal 

 wall the peptone which disappears from the 

 intestine without entering the intestinal blood 

 and lymph. His failure led him to the dis- 

 covery of a new ferment Erepsin (epciTrco, I de- 

 stroy), the action of which is to split peptone into 

 crystallizable substances. This ferment, which is 

 found in many tissues, was isolated by fractional 

 precipitation with ammonium sulphate. Two 

 parts of intestinal extract were mixed with three 

 parts of concentrated ammonium sulphate. The 

 resulting thick precipitate, consisting largely of 

 proteid was dialyzed, and the erepsin found in 

 the dialysate. 



The disappearance of peptone from the intes- 

 tine is probably therefore not to be explained by 

 the assimilation of the peptone or its reconver- 

 sion into other forms of proteid, but by the split- 

 ting of the peptone through the action of the 

 ferment erepsin. 



ABSORPTION OF FATS, FAT ACIDS, AND SOAPS 2 



Absorption of Fat. 1. Place a few drops of 

 neutral olive oil in the pharynx of a frog that 



1 COHNHEIM: Zeitschrift fur physiologisehe Chemie, 1901, 

 xxxiii, pp. 451-465. 



^ WILL : Archiv fur die gesammte Physiologie, 1879, xx, 

 pp. 255-262. These experiments are best performed upon 

 summer frogs, i. e. not during the normal period of hibernation. 



