Although hypersensibility to foods and its resultant pathologic states has been conjectured for many years, the diagnosis of this idiosyncrasy has not rested on scientific grounds until very recently. In the past, the inference that this or that food substance may in whole or in part be responsible for a diseased state rested on the observation of the patient or the physician or on both, or was made by a process of exclusion. Of recent years, more scientific and accurate methods of diagnosing food hypersensibility have been introduced. The cutaneous method consists in abrading a very small area of the skin with either a needle or a Pirquet borer. Then a small amount of the food protein is rubbed into the abraded surface. A positive reaction is indicated by the development of a well defined urticarial wheal, surrounded by a zone of erythema. This reaction usually appears within from five