A NTITOXINS 2 1 



mental properties of the toxins is their ability 

 to excite, in the organism attacked, antitoxins 

 directed specifically against them, so that for every 

 true toxin there is a corresponding antitoxin. 



In addition to these bacterial toxins we know 

 of other poisonous substances possessing similar 

 characteristics. Among these are the " zootoxins," 

 - snake venoms, spider and toad poisons, the 

 toxin of eel blood, and the " phytotoxins," 

 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, appear 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. 



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 



