CHAPTER XV 

 FERMENTS AND ANTIFERMENTS 



Bacterial Ferments. In addition to the toxins, most bacteria possess 

 certain ferments or enzymes that may play an important role in the pro- 

 cesses of disease. After toxins have destroyed body-cells, proteolytic 

 ferments, partly derived from the bacteria, aid in their digestion and 

 produce a homogeneous puriform substance. A similar condition may 

 be demonstrated in vitro in cultures of Bacillus subtilis on coagulated 

 blood-serum media when the entire tube of medium is quickly liquefied 

 into a creamy fluid resembling pus. The action of the proteolytic fer- 

 ment is also demonstrated in the liquefaction of gelatin. 



Pyocyanase is a ferment that is capable of digesting other bacteria, 

 such as Bacillus anthrax, Bacillus diphtheriae, staphylococci, and strep- 

 tococci. It has been asserted that the injection of this ferment is 

 followed by an increased resistance to infection. Some years ago pyo- 

 cyanase was manufactured extensively and its use advocated in the 

 treatment of local infections, the purpose being to effect digestion of 

 the disease-producing microorganisms. These claims have not, however, 

 been substantiated, and the treatment has been generally abandoned. 



In addition to this proteolytic ferment, bacteria may possess dia- 

 static ferments capable of converting starches into sugars; inverting 

 ferments, which may change polysaccharids into monosaccharids; 

 rennin-like ferments capable of coagulating milk, etc. Not all bacteria 

 possess all these ferments, but a study of them may aid greatly in the 

 identification of the various bacterial species. 



Similarity Between Toxins and Ferments. Aside from the definite 

 ferments that are in the nature of secretory products of the bacteria, 

 there are many points of resemblance between the toxins, both exo- 

 toxins and endotoxins, and the ferments or enzymes. It would seem that 

 the whole subject of infection and immunity is becoming more and 

 more closely identified with physiologic chemistry, especially with the 

 lipoids and lipolytic ferments. This subject constitutes today a most 

 important field for investigation. 



1. Both toxins and ferments are products of the metabolism of living 

 animal and vegetable cells, and may be extracellular (free enzymes and 

 soluble toxins) or intracellular (intracellular enzymes and endotoxins). 



254 



