96 i?. H. Chittenden — Caseoses, Casein Dyspeptone, 



Thus, this body, which corresponds to the ji deuterocaseose 

 formed by pepsin-acid, has a relatively higher content of carbon and 

 also varies in certain of its reactions, which resemble rather those 

 of a deutero, and even the protocaseose of a pepsin digestion, than 

 those of a genuine ji deutero. 



Altogether, the three caseoses separated from the sulphuric acid 

 solution of casein, while showing a certain general relationship to 

 the caseoses formed by pepsin-hydrochloric acid, are sufficiently 

 diflferent in their individual reactions to suggest at least some differ- 

 ence in their nature. 



d. Caseoses formed hy the action of trypsin. 



In subjecting casein to the action of trypsin, care was taken that 

 the ferment solution should be as free as possible from all products 

 of the self-digestion of the pancreatic tissue. Dried pancreas from 

 the ox, prepared according to Kiihne's method, was warmed with 

 0-1 per cent, salicylic acid at 40° C for 24 hours, after which the acid 

 extract was neutralized and made alkaline with sodium carbonate to 

 the extent 0-3 per cent. The alkaline solution, well thyniolized, was 

 warmed at 40° C. for several days in order to convert the albuminous 

 matters present into easily diffusible products, after which it was 

 dialyzed in running water for some time, and the solution ultimately 

 evaporated to dryness at 40° C. This residue, being extracted with 

 a small volume of water, gives a fairly pure solution of trypsin, free 

 from objectionable impurities. 



In the formation of the caseoses, 2200 grams of pure, moist casein 

 were soaked in 3 litres of 1 per cent, sodium carbonate for several 

 days, and the mixture well thymolized to prevent putrefaction. The 

 trypsin solution was then added, together with some water, and the 

 whole warmed at 40° C. At first, the mixture was quite limpid, the 

 casein being dissolved in the alkaline fluid, but after two or three 

 days, gelatinous lumps began to appear on the bottom of the dish 

 and finally a soft coagulum appeared on the surface and all through 

 the mixture, resembling the separation of antialbumid. This coagu- 

 lum gradually disappeared and at the end of five days the digestion 

 was stopped, and the alkaline fluid filtered from the undigested resi- 

 due. The latter was thoroughly washed with thymolized water and 

 the washings added to the filtrate. This residue of undigested mat- 

 ter was found to be insoluble in 0-5 per cent, sodium carbonate and 

 also in 0*2 per cent, hydrochloric acid, but on being warmed with 

 pepsin-hydrochloric acid it was in time almost completely dissolved. 



