PROTEIN SENSITIZATION OR ANAPHYLAXIS 217 



can be passively transferred to fresh animals by the serum 

 or organ extracts of the sensitized animal." Biedl and 

 Kraus, 1 omitting passive anaphylaxis, give the following: 

 "By anaphylaxis we mean that state of specific hypersen- 

 sitiveness induced in animals by protein injections, and in 

 which symptoms of poisoning follow subsequent injections 

 of the same protein in doses which would have no effect 

 upon untreated animals. ">/ With some explanation to be 

 given later we accept these definitions as quite satisfactory. 

 In the meantime it is desirable to have a clear understanding 

 of the meaning of the terms employed in discussing this 

 subject. The substance which induces the anaphylactic 

 state is generally known as the "antigen." This implies 

 that it gives rise to the production of an antibody, and the 

 selection of this word has been determined by an attempt 

 to correlate the phenomena of anaphylaxis with the theory 

 evolved by Ehrlich in explanation of the production of 

 antitoxins by treatment with toxins. In truth the " antigen" 

 of anaphylaxis is not a toxin, nor is the new substance 

 generated in the body of the treated animal an antitoxin. 

 The term " anaphylactogen" is unobjectionable, since it is 

 applicable to any substance which induces the anaphylactic 

 state. Sensitizer is a good word, and commits one to no 

 theory. The same is true of the term " sensibilisinogen" 

 used by our French confreres. The sensitizer causes the 

 body cells of the treated animal to elaborate a specific 

 proteolytic ferment which digests or splits up the sensitizer. 

 Again, following the nomenclature of Ehrlich, this ferment 

 elaborated as a consequence of the introduction of the 

 sensitizer is generally designated as the "antibody." It 

 would be equally rational to speak of pepsin as an antibody 

 to beefsteak, because the former digests the latter. The 

 theory evolved by Ehrlich in his studies on toxin immunity 

 is the product of a genius of the highest order. It has 

 stimulated research, which has resulted in discoveries of 

 the greatest importance, but the attempt to explain all 



1 Kraus and Levaditi's Handbuch d. Technik u. Methodik d. Immunitats- 

 forschung. Erganzungsband. 



