ANAPHYLAXIS 387 



Gay and Southard's definite objections to the possibility of an 

 antigen-antibody reaction are found in the following arguments 

 based on experimental observations: 



1. Sensibility persists for a long time, antibodies disappear 

 rapidly. 



2. In the serum of animals sensitive to horse serum antibodies 

 to this serurn are not demonstrable by complement fixation. 



3. Although sensitiveness can be transferred to a normal animal, 

 nevertheless a definite period of incubation must elapse before the 

 recipient becomes sensitive. 



To the first of these arguments Besredka 3 objects by saying that, 

 while it is true that sensitiveness persists for a long time, the power 

 to transmit anaphylaxis passively disappears rapidly as Otto, Richet, 

 and others have shown. 



The second contention is contradicted by the work of Nicolle and 

 Abt. 4 But since these workers made their observations upon rabbits 

 their experiments do not necessarily contradict those of Gray and 

 Southard. This point at best is a difficult one to determine, espe- 

 cially as recent investigations have shown us that under certain cir- 

 cumstances antigen and antibody may be found side by side in the 

 same serum without uniting and without therefore fixing alexin or 

 complement. 



The point of their third argument has been discussed above. 



It is clear that Gay and Southard separate distinctly the sub- 

 stance in the antigen which sensitizes from that which exerts the 

 toxic action on second injection. 



Another theory which is based on such a separation of a sensi- 

 tizing and shock-producing element in the original antigen is that 

 of Besredka. 



Besredka 5 assumes that in the injected antigen (serum) there 

 are two separate substances. One of these, the sensibilisinogen, in- 

 duces, during the time of incubation, a specific antibody (sensi- 

 bilisin). This antibody remains in part attached to tissue cells and 

 in part circulates freely in the blood. The other substance in the 

 antigen he calls " antisensibilisin." This, at the second injection, 

 reacts with the sensibilisin and anaphylactic shock results. The 

 nature of the symptoms is explained by the fact that the antibody or 

 sensibilisin is attached to cells of the central nervous system, and 

 shock can result only when such attachment is present. Thus, in 

 passive transference of sensitization, the property of hypersuscepti- 

 bility is bestowed upon the normal animal by the sensibilisin or anti- 

 body present in the circulating blood, but the significance of this 



3 Besredka. Bull, de I'lnst. Past., 6, 1908, p. 826. 



4 Nicolle and Abt. Ann. de I'lnst. Past., Vol. 22, p. 132, 1908. 



5 Besredka. Loc. cit. 



