CHAPTER XIII 



ANTITOXINS 



\ A 7"E have seen in the preceding chapter that, in 

 certain cases at least, acquired immunity is 

 due to the presence of substances developed in the 

 body of the immune animal which may escape in the 

 milk of a nursing female and give protection to its 

 young. Such protective substances are called " anti- 

 toxins," because it is evident that they, in some way, 

 neutralise the toxins of various disease germs and 

 the animal and vegetable poisons referred to abrin, 

 ricin, snake-venom. 



The German chemists, Brieger and Ehrlich, have 

 succeeded in separating the antitoxin of tetanus 

 from the milk of a goat which had been made im- 

 mune by repeated inoculations with the toxic pro- 

 ducts of the tetanus bacillus. A precipitate obtained 

 from the milk by chemical processes proved to be 

 from four hundred to six hundred times as active as 

 the milk itself, as shown by its power to neutralise 



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