Despite the obviously infectious character of scarlet fever, and its all but demonstrated dependence on a specific etiologic factor, the most industrious investigation has as yet failed to isolate a micro-organism that is universally accepted as the causative agent. Different observers in the past have found micrococci, and especially streptococci, in the blood, the scales, the throat, and in secondary lesions, but it has not yet been possible to establish the specific character of any one of the earlier described forms. They have, on the contrary, been variously thought to be responsible for the primary disorder, for the complications, and also to be accidental. In fact, streptococci have been found in the buccal secretions of healthy individuals.
Among those who have more recently devoted serious consideration to this subject and have given time and energy to its elucidation, is Medical Inspector Class of the Chicago Department of Health, who more