Specific Reactions Exhibited by Hay Fever Cases. 69 



48 (744) 



A preliminary communication on certain specific reactions ex- 

 hibited by hay fever cases. 



By George H. A. Clowes. 



[From the Laboratory of Biological Chemistry, State Institute for 

 the Study of Malignant Disease, Buffalo, New York.] 



Dunbar was the first to demonstrate conclusively that the 

 European or spring variety of hay fever is caused by the pollen of 

 timothy and other members of the graminacea^ family. He found, 

 that, even in midwinter an aqueous extract of timothy pollen 

 produced flushing and intense irritation when introduced into the 

 eye of a susceptible individual, whilst normal individuals were 

 entirely unaffected by such a procedure. 



Sufferers from the American or autumnal form of hay fever 

 (caused by the pollen of ragweed, golden rod, and other members 

 of the Composite family) exhibit a similar sensitiveness when 

 tested with aqueous extracts of ragweed pollen. This reaction 

 is also strictly specific, and only those who suffer from both spring 

 and autumnal hay fever react to the extracts obtained from both 

 varieties of pollen. The amount of pollen extract required to 

 produce flushing in the eyes of sensitive individuals varies from 

 1/20 of a c.c. of a solution of one in five hundred thousand to 1/20 

 of a c.c. of a solution of one in five hundred. This test can be 

 utilized quantitatively and affords a fair index of the measure of 

 immunity or resistance possessed by sensitized individuals. 



A specific cutaneous reaction capable of quantitative applica- 

 tion may be obtained by making a slight abrasion of the skin and 

 applying a drop of pollen extract of suitable concentration. A 

 large white welt similar to that resulting from a mosquito or bee 

 bite accompanied by a distinct itching sensation develops on 

 susceptible individuals within 15 minutes, while normal controls 

 are unaffected. A small dose of pollen extract (1 c.c. of a one in 

 a million for example) injected subcutaneously produces in highly 

 sensitized individuals an itching or prickly sensation followed 

 immediately by considerable swelling at the point of injection and 

 redness extending sometimes over an area of several inches. The 



