ANTITOXINS 3 1 



ricin, crotin, abrin, etc. It may be mentioned that 

 some of these are of somewhat more complex con- 

 stitution than the ordinary bacterial toxins. Ricin, 

 for example, appears to possess one haptophore 

 group but two ergophore groups, a toxic and an 

 agglutinating one. In the case of the snake 

 venoms it is not yet definitely known whether 

 they are haptins of the first order or of the 

 second. (See page 66.) 



The Relations Existing between Toxin and Anti- 

 toxin. The exact nature of the toxin-antitoxin 

 reaction has long been the subject of study and has 

 given rise to considerable discussion. For obvious 

 reasons most of the work has been done with 

 diphtheria and tetanus toxins and their antitoxins. 

 In order to give the reader some conception of 

 the diverging views of various authorities we shall 

 devote a few pages to a brief study of the diphtheria 

 toxin-antitoxin reaction. 



During the earlier years of toxin-antitoxin in- 

 vestigations the filtered or sterilized bouillon, in 

 which the diphtheria bacillus had grown and pro- 

 duced its " toxin," was supposed to require for 

 its neutralization an amount of antitoxin directly 

 proportional to its toxicity as tested in guinea pigs. 

 Thus, if from one bouillon culture ten fatal doses 

 of " toxin " were required to neutralize a certain 

 quantity of antitoxin, it was believed that ten 



