Since the earliest application of microbiological methods to the study of scarlet fever the streptococcus has claimed the lion's share of attention. Its significance has grown as the observations have extended. At present the streptococcus is held by some to be the actual cause of the disease, while others, and I think the majority, look on it as essentially a secondary invader on which, however, depends to a large extent the fate of the patient.
For the purpose of discussing this question it is necessary first of all to consider the occurrence and the distribution of streptococci in scarlet fever. Numerous investigations1 have indicated that streptococci occur on the tonsils of scarlet fever in far greater abundance than in health. In his study of the bacteria of the throat and skin in scarlet fever Weaver calls special attention to the enormous numbers of streptococci in the throat in this