IX. ANAPHYLAXIS 



Historical. In 1898 Richet and Hericourt showed 

 that when dogs were injected with eel serum they 

 not only failed to develop an immunity against this 

 poison, but actually became more susceptible. 

 Subsequently they made similar observations with 

 a toxin, mytilo-congestin, isolated from mussels. 

 Richet applied the term " anaphylaxis " to this 

 phenomenon to distinguish it from immunization 

 or prophylaxis. Arthus, in 1903, reported that 

 similar effects could be obtained with substances 

 ordinarily not poisonous. Thus he found that if 

 rabbits were injected with horse serum they were 

 rendered very susceptible to a second injection 

 made after an interval of six to eight days. The 

 second injection produced severe symptoms, and 

 sometimes led to death in these animals. Little 

 or no attention was paid to these observations. Fol- 

 lowing a statement made to him by Theobald Smith 

 in 1904, Ehrlich caused his pupil, Otto, to study 

 why guinea pigs which had been injected with 

 toxin-antitoxin mixtures in the course of standard- 

 ization of diphtheria antitoxin, should so often be 

 killed by a subsequent injection of horse serum. 



Independently of this the subject was being investi- 

 ng 



