74 TOXINS AND ANTITOXINS. 



Roux and Martin, who have specially studied 

 this procedure,* have shown that a horse may be 

 easily immunized by injecting into the animal the 

 toxin diluted with a third of its volume of Gram's 

 iodine solution, and in successively increasing 

 doses. The initial dose is 0.25 Cc. ; then, after 

 two days, 0.5 Cc. of the same toxin is injected, 

 and in like manner the dose is increased up to the 

 eighteenth day, when the pure toxin is injected, 

 at first in small doses, which are gradually in- 

 creased so that at the end of two or three months 

 injections of 80 Cc. of the pure toxin may be given 

 without danger; the animal is then completely 

 immunized. 



The serum of an animal rendered immune in this 

 manner contains a diphtheria antitoxin which 

 possesses high power. A guinea-pig which has 

 received an injection of o.oi Cc. of the antitoxin is 

 perfectly capable of withstanding a lethal dose of 

 0.5 Cc. of the toxin. The antidiphtheria serum 

 thus obtained, and in almost limitless quantities, 

 from an immunized animal, is capable of saturating 

 the therapeutic diphtheritic toxin, and has to-day 

 taken rank in therapeutics as the most efficacious 

 remedy in diphtheria. Injected in varying doses, 

 it confers a temporary but immediate immunity. 



* Contribution a 1' Etude de la Diphterie. AnnaL de VInstit. 

 Pasteur, vm, p. 609; Ibid., p. 640. 



