216 



Scientific Proceedings (115). 



method was employed and the protein solution injected into the 

 skin, the rapidity with which the local exhaustion can be accom- 

 plished was found to vary with the concentration of the protein 

 solution. With a 1-10 dilution of egg white, a single test done 

 on a child of six with bronchial asthma and hypersensitiveness to 

 egg, completely abolished the skin reactivity at the site of the 

 reaction. 



The duration of the exhaustion has likewise been found to be 

 dependent to some extent upon the concentration of the protein 

 solution and the method employed for producing the reaction. 

 With the 1-10 egg white solution and the intracutaneous method, 

 the reactivity of the child's skin was completely abolished for 

 three days and partially abolished at the site of the test for five 

 days. In other instances with weaker solutions, the exhaustion 

 did not persist more than twenty-four hours. 



The extent of the area in which the reactivity is abolished is 

 strictly limited to the site of the reaction. The area actually 

 occupied by the wheal becomes completely exhausted, the area 

 of the erythema partially so and beyond this the skin reacts as 

 strongly as at a fresh site. 



When two substances to which the individual gives positive 

 reactions are simultaneously applied to the same site, the reaction 

 is no stronger than that produced by the substances applied singly. 

 There does not appear, therefore, to be any summation of effect. 



Observations on the specificity of the exhaustion are not yet 

 complete, but they suggest that there is a strict specificity for 

 substances biologically unrelated and something similar to group 

 reactions for substances closely related biologically. A patient 

 reacting to ragweed and chicken feather showed a specific exhaus- 

 tion, the exhausted ragweed site reacting as strongly to chicken 

 feather as a fresh site and vice versa. With another patient, the 

 specificity of the exhaustion was found to hold true for the pro- 

 teins of almond and pea, while in a third patient giving positive 

 reactions to wheat and oat, it was found that the exhausted 

 wheat site reacted less strongly to oat than a fresh site. 



As a control series of observations, we have attempted in six 

 patients to abolish the cutaneous reactions to histamine. It 

 is, of course, well known that the application of histamine in 



