Heredity is apparently an important predisposition in most allergic persons; nevertheless, there are certain instances in which a carefully taken history fails to reveal the slightest evidence of any allergic manifestation in the patient's ancestors. Such instances suggest that clinical allergy, including hypersensitiveness of the skin, may develop spontaneously or may be artificially induced. The most thorough attempts to study the latter problem have been carried out in Schloss' clinic,1in which it was demonstrated that normal and marantic infants absorbed unchanged egg and milk proteins. The blood of such infants may contain precipitins for the food taken; by employing the intracutaneous test, positive skin reactions were obtained in about 50 per cent of these cases. In another instance,2a boy, 10 days old, was given egg-white without manifesting symptoms. His next contact with egg was at the age of 14 months, and a definite intolerance of eggs was observed.