1 62 TOXINES PRODUCED BY BACTERIA. 



whose toxophorous atom groups have become degenerated, 

 Ehrlich gives the name toxoids. He states that he has 

 found evidence that similar bodies may be directly formed 

 by the diphtheria bacillus and not as the result of sub- 

 sequent degeneration, and these he calls toxones. Such 

 observations are of importance, not only as throwing light 

 on the constitution of the toxine molecule, but also as 

 affording an explanation of how altered toxines (toxoids) 

 can act as immunising agents by stimulating antitoxine for- 

 mation. The theory may also afford an explanation of 

 what has been suspected, namely, that in some instances 

 toxines derived from different sources may be related to one 

 another. For example, Ehrlich has pointed out that ricin 

 produces in a susceptible animal body an antitoxine which 

 corresponds almost completely with that produced by 

 another vegetable poison, robin (vide supra), though ricin 

 and robin are certainly different. This may be due to the 

 fact that robin is a toxoid of ricin, i.e., their haptophorous 

 groups correspond, while their toxophorous differ. The 

 evidence on which Ehrlich's deductions are based is of a 

 very weighty character, and will be again referred to in the 

 chapter on Immunity. 



