DIPHTHERIA TOXINS. 145 



is concerned, Madsen has found that these substances, though abso- 

 lutely free from pathogenic action, are entirely equal to pure toxin. 

 In these, then, toxicity and immunizing power are entirely unasso- 

 ciated. These facts make Ehrlich's hypothesis very plausible, ac- 

 cording to which the toxin molecule contains separate groups, " hapto- 

 phore " and " toxophore." The combination of the former with 

 corresponding groups in the receptive organs furnishes the condi- 

 tions necessary and sufficient for the production of antitoxin by 

 these organs. 



TRANSLATOR'S NOTE. Park and Atkinson report quite different results in a 

 similar set of experiments. By treating horses with toxin neutralized threefold 

 (for guinea-pigs) , they produced a considerable amount of antitoxin. Even when 

 the toxin was neutralized sixfold there was a slight production of antitoxin. 

 See Proceedings of the New York Pathological Society, 1903. 



