HYDEOGEN ION CONCENTRATION AND PROTEOLYSIS. 177 



From these results it may be said that B. suhtilis produces endo-enzyme 

 and no exo-enzyme. The author may not, however, be justified in apply- 

 ing the term "enzyme" in this connection, because the proteolysis which 

 took place in flask 1 might have been brought about by any one of the 

 following agents : — 



1. Enzyme. 



2. Direct action of the living protoplasm. 



3. Enzyme and the living protoplasm. 



The distinction between these factors, in the light of present knowledge, 

 is not easily made, although the matter has been investigated by some 

 workers. For instance, Gotschhch^ would distinguish between the action 

 of enzyme and the li\'ing protoplasm as follows: "Fermentation is a 

 direct function of the living protoplasm, and serves as its source of energy," 

 while "enzyme action is not directly dependent on the living protoplasm, 

 and does not serve the organism as a source of energy." In order to 

 demonstrate these statements there are several methods; for example, the 

 use of antiseptics which kill the causal organisms but do not measurably 

 impair the enzyme. Kaufmann^ has shown that very dilute enzymes are 

 nearly as susceptible to antiseptics as are bacteria. Thus it may be under- 

 stood that the distinction between these factors is not easily made. The 

 author has taken the liberty to designate these causal substances in this 

 investigation as enzymes, and has distinguished endo- and exo-enzymes 

 according to the method employed. 



' Kolle u. Wassermann's Handbuch, V. 1, 104. 

 2 Zeit. Physiol. Chem., 1903 (39), 434. 



