78 TOXINS AND ANTITOXINS. 



and directly fatal to animals into which it is 

 injected.* 



Experiment has shown that animals that have 

 been cured of tetanus possess no immunity what- 

 ever against tetanus; nevertheless Behring and 

 Kitasato f first, and Wassermann and Kitasato later 

 on, succeeded in preparing a tetanus antitoxin. To 

 obtain this, the immunization of the animal, horse 

 or cow, is effected by injecting increasing quan- 

 tities of the toxin, more or less attenuated by mixing 

 it with Gramm's iodine solution ; the immunization 

 is easily and rapidly accomplished by the process 

 devised by Roux and Vaillard.J 



The immunized animals yield a serum which, 

 mixed with tetanus cultures, renders these innocu- 

 ous, and which enjoys an antitoxic power that 

 borders on the marvelous. § A quintillionth of a 

 cubic centimeter of the serum per gramme weight 

 of a live mouse suffices to protect the animal from 

 an otherwise fatal quantity of tetanus toxin. |1 



This serum is nevertheless powerless to preserve 

 man in cases of acute tetanus ; it confers an imme- 

 diate, but only transitory, inimunity. 



As to its mode of action, it appears to cause 

 a permanent condition of excitation or of nutri- 



* Compt. rend. Soc. Biol., 1893, p. 294; Ibid., 1894, p. 878. 



•(• Deutsch. Med. Wochenschr., 1890. 



% Annal. Instit. Pasteur, vii, p. 64. 



§ Nocard: Bull, de I'Acad. de MSdecine, Oct. 22, 1895. 



11 Naillard: Compt. rend, de I'Acad. de Sciences, cxx, p. 1181. 



