With the advent of sulfanilamide therapy it was natural that it should be tried in rheumatic faver. Despite the lack of proof that the hemolytic streptococcus is the etiologic factor in the disease, it has been postulated that the beta hemolytic streptococcus acts as a catalytic agent to start off the rheumatic cycle. It was soon shown by Swift, Moen and Hirst1and Massell and Jones,2independently, that not only is sulfanilamide of no value in active rheumatic fever but that it is definitely harmful. In January 1939 two papers appeared on the prophylactic use of the drug in susceptible rheumatic subjects, in one of which Thomas and France reported encouraging results in an adult group of ambulatory patients and in the other Coburn and Moore3were just as encouraging about a group of children in a convalescent home. With this in view, it was decided to