THEORIES RELATING TO ANAPHYLAXIS 111 



Berkefeld filter. It is rendered inactive by heating at 

 56° C. for thirty minutes . It can be made active again 

 by the addition of fresh extract from the organs. 



The same result is obtained by bringing horse 

 serum into contact with the ferment which is con- 

 tained in the extract from the organs. 



Giving up this theory of precipitins as soon as he 

 discovered that it did not tally with the facts, Doerr 

 conceived a physical theory.^ According to this^ 

 the reaction between the antigen and the antibody 

 brings with it physical modifications of the blood, 

 and these modifications produce the usual anaphy- 

 lactic symptoms. He admits the existence, in the 

 fresh scT-um of the guinea-pig, of a toxic substance 

 and of another antagonistic to it which masks the 

 first substance. When bacteria or precipitates are 

 brought into contact with complement, these bacteria 

 or precipitates absorb the antagonistic substance. 

 The toxic substance, no longer held in check, becomes 

 free — hence the anaphylactic shock. 



In other words, the anaphylactic poison is not 

 formed at the expense of the antigen, as Friedberger 

 thinks, but at the expense of the complement itself. 



This physical theory, which explains, indeed, a 

 great many phenomena, is more satisfying mentally 

 than the anaphylotoxic theory. Thus it has attracted 

 many followers (Muternich,^ Bordet,^ and others). 



It must be remembered that the physical concep- 

 tion of anaphylaxis was first formulated by us ten 

 years ago. We summed up our experiments on the 

 mechanism of anaphylaxis and anti-anaphylaxis in 

 the following terms : " In a general way, most of the 

 facts reported seem to indicate that the phenomena 

 of anaphylaxis and anti-anaphylaxis are reducible to- 

 the actions of precipitation and absorption wh?ch 



1 Wien. klin. Wochenschr., xxv., p. 331, 191 2. 



2 Comptes rend. Soc. de Biol., Ixxiii., p. 56, 1912. ^ £q^_ qH^ 



