In 1918, Schultz and Charlton1 first described the discutient phenomenon, which they obtained after the injection of 1 c.c. of normal or convalescent scarlet fever serum, intradermally, in a scarlet fever patient with a fully developed eruption. According to these writers, a blanching of the skin, together with a complete disappearance of the rash around the injection for an area of from 1 to 2 inches (2.5 to 5 cm.) in diameter occurred within from five to six hours after the injection, and persisted while the scarlatinal rash lasted. In their first series of fifty patients, forty-four gave positive reactions, with five doubtful, and one negative; while patients with other skin rashes when injected with the same serums gave uniformly negative reactions. These authors also pointed out that the injection of serum from patients in the exanthematous stage of scarlet fever did not produce this reaction. This phenomenon was investigated