THE ETIOLOGY OF SCARLET FEVER

Owing to the constancy with which hemolytic streptococci of one kind or another have been found associated with scarlet fever, they have long been considered as a possible cause of the disease. Attempts to prove their causal relation have encountered many obstacles, chief of which has been the failure to produce experimental scarlet fever. TYPES OF STREPTOCOCCI The hemolytic streptococci associated with scarlet fever do not all show the same cultural characteristics. They may be divided into two groups according to their effect on mannite. In a series of 100 cases studied in 1922 and 1923, hemolytic streptococci were found in all; 16 per cent. of these strains fermented mannite, and 84 per cent, did not ferment mannite. In 1923, we1reported experimental scarlet fever produced with one of the strains that fermented mannite. This strain was isolated from a case of scarlet fever. It produced experimental scarlet fever.