The “epidemic” form of bronchial asthma described by G. Ancona in Florence has been studied there with respect to the nature of the skin reactivity, and also in order to see whether the blood of the affected individuals contains atopic reagins. The cutaneous reaction was found to be different from that of atopic hypersensitiveness; (a) because it is quite inconstant and (b) because it is exhibited upon surface application of the excitant. Sensitizing bodies could not be demonstrated in the blood of either of the 2 sensitive individuals presenting a markedly positive skin reaction. The “epidemic” form of asthma must be placed in a special category, since it differs from the inherited form and also from the “non-sensitive” group of Cooke.