played by serum and cellular ferments. It is of fundamental importance 

 from the theoretical viewpoint ; indeed most conceptions of the mechanism 

 of the anaphylactic reaction with the exception of those which base it on 

 physical changes, involve the fundamental idea that the poison causing the 

 symptom of anaphylaxis is produced by protein cleavage mediated by fer- 

 ments. 



Friedmann and Isaac, on the basis of increased nitrogen excretion 

 after reinjection of sensitized animals, assumed the formation of a proteo- 

 lytic ferment as a result of the sensitizing injection. Heilner(&) was led to 

 the same assumption from the same type of evidence. Other observations 

 pointing to a ferment action were : first the demonstration by Fried- 

 berger(&) that anaphylatoxin is formed in vitro by the action of anti-serum, 

 antigen and complement (it is now known, however, that the anaphyla- 

 toxin is also produced by the action of agar or kaolin on normal serum) ; 

 secondly, the work of Vaughan on the toxic fraction of the protein mole- 

 cule, formed by alcohol-alkali hydrolysis of protein, with action similar to 

 the anaphylactic poison ; and thirdly, the demonstration by Biedl and 

 Kraus, and Pfeiffer and Mita, that injections of peptone produce symp- 

 toms similar to anaphylactic shock. 



With evidence of this type, investigators naturally set to work to 

 demonstrate a ferment for the protein used in sensitization. Almost simul- 

 taneously, Abderhalden and Pincussohn, and Pfeiffer and Mita reported 

 a proteolytic ferment which accumulates during the preanaphylactic stage, 

 diminishes during shock and anti-anaphylaxis, and then appears again 

 later in increased amount. Pfeiffer and Jarish later confirmed these 

 results with the dialysis method of Abderhalden. They found that the 

 proteolytic power is present on the sixth day and persists 30 to 40 days. 

 They also demonstrated the proteolytic power in passive anaphylaxis, but 

 found that in anti-anaphylaxis it is lost for three to four days. Further- 

 more, their results seemed to show that the smallest amount of antigen 

 giving rise to ferment formation, corresponds closely to the minimal sen- 

 sitizing dose as shown by the temperature drop after reinjection. Zunz 

 and Gyorgy confirmed much of this work, using the accurate Van Slyke 

 method to determine amino nitrogen production in mixtures of serum from 

 a sensitized animal and the specific antigen. 



The results of Jobling and Petersen and Eggstein, while agreeing in 

 some particulars with the conclusions just cited, contain points of dis- 

 agreement. They reached the following conclusions regarding serum 

 ferments in anaphylaxis: (1) The ferments are practically unaltered 

 by the primary injection of foreign protein. (2) During the course of 

 sensitization, the injection of antigen is followed by mobilization of a 

 non-specific protease, and the mobilization increases in intensity and 

 rapidity as the maximum period of sensitization is reached. (3) Acute 

 shock is accompanied by: (a) instantaneous mobilization of a large amount 



