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Specific Exhaustion of Cutaneous Reactions. 215 



develop in a few minutes, consist essentially of a wheal and ery- 

 thema, and fade out completely in one to two hours. The skin 

 then appears normal. There is no visible evidence of cell destruc- 

 tion. Such reactions may be obtained with extracts of pollen, 

 animal dandruff and feathers, with food proteins, with foreign 

 serum, and occasionally with bacterial or other proteins. 



This type of cutaneous reaction has little in common with 

 the local cutaneous reactions to tuberculin, typhoidin, luetin, 

 and mallein. Here the reaction does not usually develop for 

 12 to 24 hours; it is characterized by induration and persistent 

 signs of inflammation, requires many days to fade out entirely 

 and c early involves cell destruction. Zinsser 1 has recently shown 

 that the local tuberculin reaction in the guinea-pig is independent 

 of the development of a state of anaphylaxis and it is highly 

 probable that the same holds true for the reactions of this type 

 produced by other substances of bacterial origin. 



Although it has commonly been assumed that the immediate 

 skin reactions with urticaria-like lesions are manifestations of 

 anaphylaxis, it has not been demonstrated that the mechanism 

 consists of an antigen-antibody reaction. Similar reactions may 

 sometimes be obtained with non-antigenic substances such as 

 aspirin, salicylates and quinine, and there are a few substances, 

 notably histamine, morphine and pituitrin, which produce this 

 type of reaction in normal individuals. It appears to be essen- 

 tially a vascular phenomenon with localized edema. 



In an effort to determine the nature of these urticaria-like 

 skin reactions we have studied their exhaustibility by a simple 

 procedure in five hypersensitive patients, the subjects of hay 

 fever or bronchial asthma. Our results indicate that the reac- 

 tivity of the skin may readily be abolished in the area involved 

 in the reaction. This exhaustion has been accomplished with such 

 biologically different substances as egg white, extracts of ragweed 

 and chicken feathers, the proteins of almond, pea, oat and wheat. 

 In the experiments in which the cutaneous method of eliciting the 

 reaction was employed, the exhaustion was usually not complete 

 until the reaction had been repeated five or six times on the same 

 site, at intervals of one or two hours. When the intracutaneous 



1 Zinsser, H., Proc. Soc. Exp. Biol, and Med., 1921, xviii, 123. 



