20 



Scientific Proceedings (69). 



Our experiments have shown that also the physico-chemical 

 changes following the specific interaction between the antigen and 

 antibody influence the colloidal conditions of the medium in the 

 same manner. 1 Our records show that both stalagmometer and 

 refractometer register the increase of dispersion in the immune 

 serum following the addition of the specific antigen and parallel 

 with it the actual measurements of the antitryptic titer of the 

 serum show a steady diminution of the power of this serum to 

 check the activity of its own proteolytic ferments. 2 



In anaphylaxis the latter process takes place, namely, if a 

 suitable amount of antigen is injected into a sensitized animal, 

 the interaction between the specific antibodies and the antigen 

 produce a physico-chemical change in the serum, followed by a 

 diminution of its antitryptic activity. Once the balance between 

 the tryptic and antitryptic powers of the serum is destroyed, the 

 proteolytic ferments may attack the protein of the serum with the 

 production of toxic split products, and anaphylactic shock follows. 8 



That the mechanism of anaphylaxis rests on the disruption 

 of balance between the tryptic and antitryptic properties of the 

 serum is especially evident from our experiments in which we 

 succeeded in preventing anaphylactic shock in experimental 

 animals by increasing the antitryptic power of their serum at 

 will before subjecting them to shock. 4 In doing so we found that 

 practically any substance which caused the rise in antitryptic 

 titer of the serum of experimental animals, protected them also 

 from the subsequent anaphylactic shock. We found also that 

 all such substances are toxic by themselves if injected in sufficient 

 quantity. The mechanism of this protection seems to be as 

 follows. 



The introduction of poisons in quantities not sufficiently large 

 to kill the animal outright is followed by the death of the tissues 

 immediately affected by the poison. With the death of the tissues 



1 Bronfenbrenner, Proc. Soc. Exp. Biol, and Med., 1914. XII, p. 4. 



' Bronfenbrenner, Mitchell and Titus, Biochemical Bulletin. 



* Bronfenbrenner, Penna. State Med. Journ., October, 1914; also Journ. Exp. 

 Med., 1915, Vol. XXI, p. 480. In a current number of the Journ. of Exp. Med., this 

 view of anaphylaxis is corroborated by Jobling, Peterson and Eggstein. 



4 Bronfenbrenner and Schlesinger. 



