Abstract
One of the reasons why the importance of streptococci in the etiology of rheumatic fever and various other forms of arthritis, especially chronic infectious arthritis, is not sufficiently recognized is the fact that bacteriologists have been too much concerned with differences in cultural reactions and not enough with the peculiar infecting power of the streptococci isolated, especially immediately after isolation. The diseases comprising the arthritic group, generally considered as being due to streptococci, are so different in their clinical and pathologic manifestations, and the cultural properties of streptococci are so variable,1that the requirements stressed by some2that all streptococci isolated must have identical cultural reactions to be of significance is fallacious. In a long series of experiments, I have shown that the streptococci isolated in cases of rheumatic fever3and chronic infectious arthritis,4irrespective of whether they are green-producing, indifferent or slightly hemolytic, possess on