54 POISONOUS PROTEINS 



are possessed of a degree of specificity not char- 

 acteristic of the alimentary enzymes. The fer- 

 ment found in each organ or each kind of tis- 

 sue digests especially, more rapidly and com- 

 pletely, the organ or tissue in which it is found. 

 The liver ferment readily splits up liver tissue 

 but is less effective in its action on the proteins 

 of other organs. In the second place, the prod- 

 ucts of autolytic cleavage differ from those of 

 enteral digestion. Pepsin forms large amounts 

 of primary cleavage products, such as proteo- 

 ses and peptones. These, especially the former, 

 are highly poisonous, and would have a most 

 disastrous effect were they liberated parenter- 

 ally. The autolytic enzymes produce none or 

 only traces of these primary split products. 

 They cleave deeper and their chief products are 

 the relatively harmless amino acids and purin 

 bodies. From tryptic. digestion the autolytic 

 enzymes differ in several particulars. Trypsin 

 acts in feebly alkaline solution while autolysis 

 proceeds most rapidly in slightly acid media. It 

 is more than probable that the intracellular tis- 

 sue is always feebly acid. Tryptophan, a prod- 

 uct of tryptic digestion, is seldom or never 

 found among the autolytic products. In auto- 

 lytic cleavage of proteins much more amjnonia 

 is found than in tryptic digestion. Further- 



