This study of an isolated colony showed that of seven children who escaped the epidemic streptococcus
infection none developed rheumatic symptoms; and that of seventeen children who contracted the epidemic streptococcus
infection, fourteen developed
acute rheumatism and three showed no recognizable rheumatic manifestations. The seven children who failed to contract
infection with Streptococcus hemolyticus showed clearly that susceptible individuals may live in dose association with an epidemic of
acute rheumatism, develop no rise in
antistreptolysin titer and maintain excellent health. The patient with
congenital heart disease demonstrated that a non-rheumatic subject may be infected with a highly effective strain of hemolytic streptococcus, and develop a typical antibody response, yet escape all rheumatic manifestations. The two patients who, although infected with the epidemic strain, failed to show any antibody response, also failed to develop rheumatic recrudescences. Environmental,
dietary, age and the other factors investigated did not appear to be significant in this outbreak of
acute rheumatism. Three factors appeared to determine the development of the fourteen recrudescences: (1)
infection with a highly effective agent; (2) the disease pattern, peculiar to each rheumatic subject; (3) the intensity of the immune response of the patient as indicated by the rise in
antistreptolysin titer.