STUDIES ON THE BIOLOGY OF STREPTOCOCCUS : IV. THE OCCURRENCE OF STREPTOCOCCUS SCARLATINAE IN CONVALESCENCE AND IN THE COMPLICATIONS OF SCARLET FEVER.

1. A group of streptococci which agglutinate with scarlatinal immune sera has been isolated from the throats of 65 per cent of cases of scarlet fever during the 1st week of the disease. 2. Strains of hemolytic streptococci belonging to this group have been isolated from the throats of patients at the termination of quarantine (30 days). 3. Hemolytic streptococci are found most frequently in the throat in convalescent patients in whom the tonsillar inflammation has not entirely subsided. 4. The complications occurring in scarlet fever may be due to the original scarlatinal strain or may be the result of a secondary infection with pyogenic strains of streptococci.