ACTION OF THE ENZYMES. 125 



diamino-acids , many in number and differing markedly from 

 the protein itself or any of the intermediate products. In 

 the passage from the proteins to the ultimate digestion 

 ,roducts we find that the substances become progressively 

 more simple. Physically we pass from those which are 

 typical colloids, that is to say, amorphous substances with 

 high molecular weights, practically no diffusibility, and no 

 osmotic pressure, to crystalline bodies of a low molecular 

 weight and of a ready diffusibility. Whereas the original 

 substances are insoluble or only slightly soluble, the ultimate 

 products are, generally speaking, freely soluble. Qualita- 

 tively, the digestion under the influence of alkali-proteinase 

 does not differ materially from that under acid-proteinase; 

 quantitatively, alkali-proteinase is the more powerful enzyme, 

 producing the substances to be enumerated below much more 

 rapidly and in greater quantities than when acid-proteinase 

 is used. 



In order to obtain the end products of alkali-proteinase 

 digestion for study, it is best to allow pure pancreatic juice 

 obtained from a PAWLOW pancreatic fistula to act upon a 

 protein, such as fibrin. The mixture is covered with toluol 

 or some other antiseptic which prevents the development 

 of bacteria but does not interfere with the activity of the 

 alkali-proteinase, and the whole is kept at a suitable tem- 

 perature for varying periods of time. Many of the products 

 of alkali-proteinase digestion can be found shortly after the 

 ferment has been allowed to act upon the protein, but cer- 

 'ain of the rare products cannot be found in sufficient quan- 

 jties until the reaction mixture has been allowed to stand 

 even for months. In order to get a conception of the quan- 

 titative relations between the various digestion products at 

 any desired time, the action of .the ferment can be stopped 

 by boiling the reaction mixture. Frequently the autodiges- 

 tion of the pancreas and other organs has been used for the 

 study of the products of alkali-proteinase digestion, but in 

 these cases it cannot be said with certainty that some of 



