284 president's addkess — section l. 



It is true that Abderhalden affirms the specific nature of these 

 ferments, and has applied this theory to the practical diagnosis of 

 such conditions as pregnancy, and malignant growths such as 

 cancer, but numerous workers have failed to confirm his results, 

 and the recorded observations are very contradictory as to the 

 value of the method. 



Friedberger and his followers have suggested a modification 

 which accords well with many of the facts,, and is far-reaching in 

 its application. According tO' this view, anaphylaxis results from 

 the combination of complement with an antigen-antibody com- 

 plex, and as a result the complement splits up the antigen, giving 

 rise toi joroteoelastic substances which are toxic. The following 

 experiments furnish strong evidence in support of this view : -.— 



(1) If well washed sensitised red corpuscles are injected into' the 

 jugular vein of a normal guinea pig. the result is anaphylactic 

 shock and death. 



(2^ Again, if similar sensitized red cells are submitted to the 

 action of an excess of fresh guinea pig complement, then centri- 

 fuged off and the supernatant fluid injected intravenously, the 

 same result occurs. 



(3) If a fresh serum and its anti-serum are mixed togetlier and 

 the resulting precipitate is centrifuged off, well-washed, and then 

 submitted to the action of fresh complement and injected, shock 

 and death are caused. 



(4) Lastly, if sensitized bacteria arei acted on by fresh com- 

 plement, then centrifuged off and the supernatant fluid injected, 

 the result is the same. 



Thus, any one oif a variety of antigens acted on by its appro- 

 priate antibody^, and then by fiesh serum containing complement, 

 is effective as a source of " anaphylatoxin " ; further, a point 

 of great importance, if the fresh serum is heated to 56" C. so as 

 to' destroy the complement, then no (tnaphi/Iaxts is jji-od iiccl by 

 the injection. A further point is that it is of no importance what 

 bacteria are used as antigen, and, as Novy and de Kruif have 

 recently shown, even trypanosomes treated in the same manner 

 are; effective in producing anaphylaxis. 



So Fi'iedberger, von Pirquet, Friedman and other have seen 

 in infection of the animal body with bacteria, and the resulting 

 symptoms and effects, only the phenomena due to anaphylaxis. 

 The incubation period of a disease is, according to this view, 

 simply the interval required after infection for the antibody to be 

 produced, and this then reacts with the antigen, i.e., the invading 

 bacteria, and complement, to produce toxins giving rise to all the 

 symptoms and other effects proper to the disease. 



It must be admitted that this is a most attractive generaliza- 

 tion, fascinating in its simplicity and far-reaching effects, but as 

 we have seen from past experience of generalizations there is a 

 grave danger in accepting so sweeping a hypothesis, the danger 

 of trimming new facts and observations to make them fit the 

 hypothesis. 



