The cutaneous test is accepted today as a diagnostic procedure in the study of human hypersensitiveness. The marked immediate cutaneous reaction that can be confirmed repeatedly is the evidence of the hypersensitiveness of the skin. In the writer's article “On Constitutional Reactions,” in this issue of the Journal (page 000), it is shown by a table of cases that the typical cutaneous reaction is likewise indicative of clinical hypersensitiveness in at least 95 per cent of the cases reacting to the extracts of such airborne substances as pollens, powdered root of orris and animal danders. Bronchial asthma was early recognized as the chief clinical manifestation of the hypersensitive state in human beings and many of the cases were readily diagnosed by testing with extracts of such substances as those mentioned above, easily conceived and long known clinically to be important excitants of an attack.