58 Biology of Bacteria 



called pyocyanase. The authors reach the rather hasty con- 

 clusions that the cessation of growth of bacteria in cultures 

 depends upon the generation of enzymes; that the enzymes 

 destroy the dead bacteria; that the enzymes will kill and 

 dissolve living bacteria and destroy toxins, and, therefore, 

 are useful for the treatment of infectious diseases; and 

 that antitoxins are simply accumulated enzymes which the 

 immunized animals have received during treatment, and 

 which, appearing in the serum, produce the effects so well 

 known. 



It is probable that many of the toxic effects of bacteria 

 and their cultures depend upon enzymic substances, the 

 nature of which we do not yet understand. 



