PROPERTIES OF ANTISENSITIZERS. 297 



receptors capable of combination with certain active principles 

 (normal sensitizers) of normal rabbit serum. The receptors affected 

 by the injection are reproduced in excess by a cellular reaction and 

 poured into the serum, which fluid becomes endowed with the 

 property of neutralizing the specific rabbit > ox sensitizer. Con- 

 sequently, the antisensitizer is composed of receptors identical 

 with, or similar to, the receptors in the ox corpuscles that unite 

 with the sensitizer.* It should then act as these corpuscle recep- 

 tors do, for it is, so to speak, only a solution of such receptors in 

 serum. This conception of the antisensitizer is indeed the one 

 recently accepted by Morgenroth.f 



The inaccuracy of such a conception founded on Ehrlich's theory 

 is evident from the facts we have just offered. In the first place, 

 if the antisensitizer were identical with the corpuscle receptors 

 used, it would not combine with the sensitizer already saturated 

 with these receptors, in other words, bound to the corpuscles. And 

 the cure of sensitized cells by antiserum would be impossible. 



Moreover, if the antisensitizer were identical with the receptors 

 in question, it is evident that any substance which would combine 

 with one would combine with the other. Normal rabbit serum con- 

 tains, as we know, no substances that combine with the receptors 

 of ox corpuscles (that is, these corpuscles remove nothing from the 

 serum), and yet this serum is so avid of antisensitizer that it 

 can compete successfully with rabbit > ox sensitizer in combining 

 with it. Rabbit > ox serum, moreover, even when entirely de- 

 prived of its specific sensitizer for ox corpuscles, will still saturate 

 antisensitizer. And, what is more, since the same antisensitizer 

 unites with various sensitizers indifferently, whether or not they 

 combine with ox corpuscles the result is that antiserum treated with 

 sensitized ox corpuscles no longer protects other varieties of sen- 

 sitized corpuscles. 



The theory under discussion is also in direct opposition to the 

 fact that antiserum removes from sensitized corpuscles their power 

 of absorbing alexin. It is evident that if the antisensitizer were 

 made from corpuscle receptors, its combination with the sensitizer 



* According to Ehrlich's terminology, these receptors all have the same hapto- 

 phore group. 



f Studies on Immunity, Ehrlich-Bolduan, John Wiley and Sons, p. 241. 



