The author regards rheumatic fever as a specific disease, though he admits there are certain arguments against this assumption. One argument hinges on the relationship of rheumatic fever to streptococcic infections. Until the question of whether hemolytic streptococci are the only infectious agents in rheumatic fever has been answered, the concept of this condition as a clinical entity should not be discarded.
Midchildhood is the period of greatest susceptibility to first attacks, partly, in all probability, because of more frequent exposure to infection during this period.
The prevalence of rheumatic fever is determined by both environment and inherited tendencies. Among the environmental factors, climate, season and living conditions are important. Among the elements in living conditions which seem to be important are poverty, crowding and dampness. There is also good evidence from a study of rheumatic families that there is an inherited tendency toward the acquisition of rheumatic fever.