ANTITOXINS 



33 



tion by means of his " partial saturation " method. 

 Certain experiments had led him to believe that the 

 original antitoxin on which he had based his " unit " 

 determinations, while able to neutralize 100 fatal 

 doses (per unit) really represented 200 " binding 

 units," and that the toxic bouillon really contained 

 several kinds of poisonous substances able to com- 

 bine with antitoxin. 



He now believes that the diphtheria bacilli excrete 

 at least two such poisons, " toxins " and " toxons ; " 

 that these very quickly decompose to a greater or 

 less extent forming various " toxoids." 



