CHAPTER V 



THE ORIGIN OF ANTITOXIN THE SIDE-CHAIN 



THEORY 



THE theory that antitoxins are derived from their appropriate 

 toxins deserves a short consideration, since it is so inherently 

 probable. When we consider the large numbers of toxins which 

 give rise to their antitoxins when injected into animals, and see 

 that each antitoxin has a direct action on its own toxin, but none 

 or practically none on others, the most likely explanation of the 

 phenomenon is that the animal tissues have the power of splitting 

 the toxin into two parts, or of otherwise modifying it, and that 

 this modified toxin can combine with unaltered toxin and form 

 antitoxin. Some experimental evidence is forthcoming to support 

 this view. Thus it is found that diphtheria toxin which has been 

 submitted to the action of an electric current loses its toxicity, but 

 retains that of producing immunity on injection. Some thought 

 that this was due to the direct transformation of the toxin into 

 " artificial antitoxin," and it was hoped that a similar change 

 might be brought about in the human body in disease by the use 

 of electricity. The explanation of the phenomenon is very 

 simple. The electrolysis of the water in which the toxin is 

 dissolved gives rise to oxidizing substances which transform the 

 toxins into toxoids, the immunizing virtues of which we have 

 already seen. There is no method by which antitoxin can be 

 prepared other than by the injection of toxins into suitable 

 animals. 



That antitoxin is not a direct transformation product of toxin 

 appears probable from the following considerations, none of which 

 perhaps is conclusive, but which together make up a body of 

 evidence of some importance : 



i. The injection of a certain amount of toxin will give rise, 

 under suitable circumstances, to the formation of much more 



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