ANAPHYLAXIS 389 



ficity of the reaction, the incubation time, and the phenomena of 

 passive sensitization. 



This assumption gained much further support when Doerr and 

 Russ 13 succeeded in applying quantitative methods to the study of 

 the anaphylactic antibody. Their methods consisted in precipitating 

 sera in rabbits. With these they then passively sensitized guinea 

 pigs, subsequently testing them with antigen 24 hours later. To 

 arrive at quantitative results they developed two reliable methods. 

 These consisted in: 1. Intraperitoneal sensitization of guinea pigs 

 with constant quantities of titrated precipitating serum. Twenty- 

 four hours later intravenous test with diminishing amounts of specific 

 antigen. 2. Intraperitoneal sensitization with diminishing quanti- 

 ties of the titrated precipitating serum, and 24 hours later intrave- 

 nous tests with constant amounts of antigen. 



In this way they showed that there was a direct relationship be- 

 tween the power of a serum to convey anaphylaxis passively and its 

 contents of precipitins. We may elucidate this by an example from 

 their work. They possessed a rabbit serum which gave precipitation 

 with sheep, goat, beef, pig, human, and horse sera, but not with 

 chicken serum. The precipitation titre of this serum for the sera 

 mentioned varied from 1 in 20,000 in the case of sheep and goat 

 sera, to 1 in 100 in the cases of the human and horse sera. When 

 guinea pigs were injected intraperitoneally with 1 c. c. of this serum, 

 and after 24 hours were intravenously injected with the various sera 

 mentioned above, in decreasing quantities, the sera which were pre- 

 cipitated in the highest dilutions gave anaphylactic shock in the 

 smallest quantities. Those sera in which no precipitin or little had 

 been present gave little or no reaction by this method even where con- 

 siderable quantities were used. Thus in animals prepared by 1 c. c. 

 of the antiserum (precipitated in dilutions of 1 in 20,000) sheep 

 serum caused death when injected in doses of 0.006 c. c,, whereas 

 horse serum (which was precipitated only in concentration of 1 to 

 100) gave slight symptoms only when 2 c. c. were employed for re- 

 injection and chicken serum (non-precipitable by the antiserum) 

 gave no reaction in similar doses. 



In this, then, we have a definite quantitative analysis which 

 proves that the power to sensitize passively is in direct relation to the 

 antibodies against the protein present in the sensitizing serum. 

 Whether or not this means the precipitins we consider relatively un- 

 important inasmuch as we have already made clear that we believe 

 precipitins, complement-fixing antibodies and agglutinins to be one 

 and the same thing. 



We may therefore accept, as a definitely determined fact, that 

 anaphylaxis is directly or indirectly the result of the reaction within 



13 Doerr and Russ. ZeitscTir. f. Immunitdtsforschung, Vol. 3. pp. 181 

 and 706, 1909. 



