302 INFECTION AND IMMUNITY 



quently, by a rapid liberation of the toxic fraction, and injury to the 

 animal results. This view has been expressed in slightly different form 

 by Richet '■ and has been more clearly formulated and experimentally 

 supported by Vaughan and Wheeler ^ who were actually able to extract 

 from various proteids toxic substances which gave rise in animals to a 

 symptom complex not unlike that of typical anaphylaxis. (Extrac- 

 tion with alkalinized seventj'^-per-cent alcohol.) 



Not entirely unlike these views is the hypothesis advanced by Gay 

 and Southard,' who assume that a part of the proteid introduced on first 

 injection is assimilated and removed, but that another part, unassimi- 

 lable, remains in the circulation and exerts a constant irritation upon 

 the tissue cells, rendering them abnormally susceptible to reinjections 

 of the same substance. They speak of this toxic or irritating, non- 

 assimilable substance as "anaphylactin," and believe that in passive 

 sensitization it is the transference of this element which renders the 

 recipient anaphylactic. 



Opposed to the opinions of most other workers is that expressed 

 by Besredka.^ Besredka believes that the substance which produces 

 sensitization is not identical with that which gives rise to the symptoms 

 onreinjection. According to his conception of the process, the sensitiz- 

 ing injection contains an active element (called by him " sensibilisino- 

 gen"), which gives rise in the injected animal to a specific antibody 

 (" sensibilisin ") . This sensibilisin circulates in the blood and is stored 

 by the cells of the central nervous system. On reinjection of the same 

 proteid, a reaction takes place between the anchored sensibilisin and a 

 third substance, present in the proteid and not identical with sensibili- 

 sinogen, which acts typically upon the nerve cells and gives rise to the 

 symptoms. This third substance he speaks of as " antisensibiHsin." 

 That the process of anaphylaxis takes place probably in the nervous 

 system is rendered plausible by the fact that ether narcosis seems to 

 prevent its occurrence (a fact maintained by Besredka but contradicted 

 by Rosenau and Anderson). Furthermore, direct introduction of the 

 second dose into the brain gives rise to more rapid and violent anaphy- 

 laxis than when any other route is chosen. Besredka calls attention to 

 the fact, furthermore, that no anaphylactic symptoms occur when the 

 serum of a sensitive animal is introduced into another animal simul- 



> Richet, Ann. de I'inst. Pasteur, xxi, 1907. 



2 Vaughan and Wheeler, Jour. Infect. Dis., iv, 1907. 



» Gay and Southard, loc. cit. 



' Besredka, Ann. de I'inst. Pasteur, 1907 and 1908. 



