CHAPTER XIX 

 ANAPHYLAXIS OR HYPERSUSCEPTIBILITY 



PHENOMENA OF ANAPHYLAXIS 



The phenomena now grouped together under the heading of anaphy- 

 laxis and hypersusceptibility have but recently become the subject of 

 systematic experimentation. Nevertheless, manifestations now recog- 

 nized as belonging to this category, had not escaped the attention of a 

 number of the earlier workers in immunity. 



By anaphylaxis is meant the following train of phenomena: When 

 a foreign proteid is introduced by subcutaneous, intraperitoneal, intra- 

 venous, or subdural injection (or in some cases by feeding) into the 

 animal body, after a time there will appear a specific hypersuscepti- 

 bility of the animal for this proteid. After a definite interval, a second 

 injection of the same substance, harmless in itself, will produce violent 

 symptoms of illness and often rapid death in an animal so prepared. 

 The phenomena are not limited to any given class of proteids, but are 

 manifest in the case of animal, vegetable, and bacterial proteids, and 

 within certain limits are specific. 



As early as 1893, Behring^ and his pupils ^ had noticed that animals, 

 highly immunized against diphtheria toxin, with high antitoxin content 

 of the blood, would occasionally show marked susceptibility to injections 

 of small doses of the toxin. 



The phenomena observed by them was interpreted as an increased 

 tissue susceptibility to the toxin, and Wassermann, reasoning on the 

 basis of Ehrlich's side-chain theory, formulated the conception that the 

 increased susceptibility was due to toxin receptors, increased in number 

 by immunization, but not yet separated from the cells that had produced 

 them; the cells thereby becoming more vulnerable to the poison. In 

 the same category belongs the observation of Kretz, who noticed that 

 normal guinea-pigs did not show any reaction after injections of innocuous 



1 Behriny, Deut. med. Woch., 1893. 



^Knorr, Dissert., Marburg, 1895; Behring und Kitashina, Berl. klin. Woch,, 

 1901. 



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