ANAPHYLATOXIN (PROTEIN POISON) 551 



tated and hastened by using immune serum specific for any particular 

 bacterial or other protein. 



These results indicate that fresh normal guinea-pig serum contains a 

 normal thermolabile non-specific proteolytic ferment capable of split- 

 ting some, through probably not all, proteins, a view advanced by 

 Vaughan many years previously. After sensitization, a specific proteo- 

 lytic ferment is produced for the particular protein injected, the presence 

 of the specific in addition to the normal ferments constituting the differ- 

 ence between normal and sensitized animals. 



Since these studies show that, when incubated, with normal serum, 

 bacteria and certain other proteins yield a soluble and active poison, 

 the question naturally arises why this reaction does not occur when 

 these proteins are first injected directly into the blood? Vaughan has 

 answered this question by assuming that the ferment is in a more avail- 

 able form in the serum than it is in the blood, since the ferment is prob- 

 ably largely a leukoprotease mainly derived from the disintegration of 

 leukocytes. Or it may be that the cleavage is carried on in the circulat- 

 ing blood beyond the point of the products constituting the protein 

 poison, or that the inclusion of the foreign protein by the phagocytes may 

 delay the disruption of the former. 



While there is this consensus of opinion regarding the role 

 poison in the production of anaphylaxis, there is some diversil 

 ion regarding the source of the protein matrix, i. e., the prol 

 broken down, especially in view of the fact that mixtures of kaolin and 

 normal guinea-pig serum produce the poison. It has been suggested 

 (a) That the kaolin, agar, bacteria, etc., absorb the complement from 

 the serum, and that this renders the serum poisonous; (6) that the poison 

 is preformed in the serum, but that its action is neutralized by some 

 other constituent of the serum that is absorbed; (c) that the absorption 

 of some constituent of the serum leads to a breaking-up of serum pro- 

 teins, with liberation of the poison. The latter view, as shown by Job- 

 ling and Petersen, 1 appears to be the most plausible. These writers 

 believe that the normal tryptic or proteolytic ferment of the blood is 

 held in check by an antiferment of the nature of unsaturated fatty acids, 

 and that laokin, bacteria, agar, etc., remove this antitryptic influence 

 by absorbing the lipoidal antiferment, setting the ferment free, which 

 then acts upon the serum protein, producing the toxic protein poison 

 (serotoxin). While Vaughan, Friedberger, and their collaborators 

 believe that the protein poison is derived from the injected protein, 

 1 Jour. Exper. Med., 1914, xix, 459 and 480. 



