ANAPHYLOXIS. 93 



It can hardly be conceived that horse serum has the ability to 

 increase its amount of poison as can bacteria and other organisms 

 capable of self reproduction. Rosenau and Anderson have de- 

 termined quite definitely that the reaction is due to a difference 

 in the susceptibility of individuals and not the toxicity of the 

 serum. 



v. Pirquet and Schick conclude that the phenomenon is due 

 to the presence of specific anti-bodies. According to these in- 

 vestigators the anti-bodies are not precipitins, for man does not 

 produce the precipitins readily with horse serum in children 

 three weeks are required before the precipitins can be detected 

 and are^ found in the blood only from four to nine weeks. The 

 "inline li ate reaction" which occurs when the second injection of 

 horse serum is made twelve to forty days after the first, Pirquet 

 and Schick explain as being due to the already present serum 

 anti-bodies which combine with the immunizing substance in serum 

 and produce poisonous substances, which in turn produce the 

 disease. 



Gay and Southard, in 1907, reported experiments which in- 

 dicate that the theory of Pirquet and Schick is untenable. These 

 investigators believe that "sudden death" in guinea pigs "sensi- 

 tized to horse serum" is due to a substance they call "anaphylac- 

 tine." This substance is found in normal horse serum, is not 

 absorbed by the tissues of the guinea pig and is eliminated slowly. 

 The anaphylactine in the guinea pig increases the avidity in the 

 cells of the guinea pig, so that when more serum is injected the 

 cells are "overwhelmed in the exercise of their eliminating func- 

 tions, and functional equilibrium is so disturbed that local or 

 general death may follow." Rosenau and Anderson had shown 

 that the hypersusceptibility of the guinea pig for a certain protein 

 is manifested upon a second injection of the corresponding protein. 

 Later they showed that the substance anaphylactine is specific 

 in the same sense. These investigators could not demonstrate 



o 



this substance in the blood of the sensitized guinea pig during the 

 incubation period, nor at any time in the blood serum of man, 

 monkeys and cats. 



The investigations on the phenomenon of hypersusceptibility 

 of guinea pigs to horse serum in connection with serum disease 

 in man, has lead to a considerable advancement in the methods 



