THE NATURE OF THE POISON, ANAPHYLATOXIN 137 



number of groups arrayed around the poison group of the protein; 

 the similarity or identity of the symptoms of anaphylaxis irrespective 

 of the protein depends upon the liberation of the poison nucleus 

 (common to all proteins) in a relatively free state. The induction 

 of passive sensitization depends upon the injection of this specific 

 enzyme, which is present in the serum of a sensitized animal, into a 

 non-sensitized animal. 1 



Vaughan regards the formation of a specific proteolytic enzyme in 

 response to the injection of alien protein into the tissues as a protec- 

 tive mechanism to rid the body of foreign substance; the theoretical 

 importance of this conception as a purposeful reaction is clearly 

 shown in bacterial infections. The incubation period of many bac- 

 terial infections is about two weeks, during which clinical symptoms 

 are not pronounced. This is interpreted as the time required by the 

 cells of a host to mature a specific enzyme capable of disintegrating 

 the alien protein (bacterial cells). The symptomatology of bacterial 

 disease is caused largely by the liberation of the poisonous nucleus 

 of the bacterial protein in special tissues or organs. Natural immunity 

 to bacterial disease, according to this theory, is due to the inability 

 of the organism to grow in the tissues of the host; active immunity 

 is conferred on the host by the presence of a persistent enzyme which 

 will disintegrate the specific organism whenever it is reintroduced 

 into the body. 



Chemically, the poison nucleus or endotoxin is stated by Vaughan 

 to resemble beta-imidazoleethylamine, described previously. 2 The 

 specificity of the anaphylactic reaction depends upon the cleavage of 

 the protein molecule by a specific proteolytic enzyme with the libera- 

 tion of a non-specific poisonous product of protein degradation. 

 Abderhalden 3 and his associates have demonstrated proteolytic 

 enzymes in the blood stream. 



Friedberger 4 has shown that a poison may be obtained by incubating 

 the inactivated serum of a sensitized animal with an excess of com- 

 plement and homologous (sensitizing) protein, which, when injected 

 into guinea-pigs, elicits the symptoms of anaphylaxis. It is not 

 true toxin, for no antibody is produced in response to repeated, sub- 

 lethal injections; it appears to differ from Vaughan's poison in that 



1 The importance of the degradation of protein in the alimentary tract can be appre- 

 ciated in the light of what has been stated about anaphylaxis. 



2 See page 76. 



3 Zeit. f. physiol. Chem., 1912, Ixxxii, 109; Abwehrfermente des tierischen Organismus, 

 Berlin, 1913. 



4 Zeit. f. Immunitatsforsch., iv, 636; vii, 94; Ueber Anaphylaxie, Ibid., 1911, ix, 394 

 (in collaboration with Goldschmidt, Schmanowsky, Schilltze, and Nathan). 



