Rheumatic infection is recognized as the most common etiologic factor in the forms of heart disease encountered in childhood and early adult life, although the symptoms of heart involvement at the time of the acute infection are often so slight as almost to escape detection. These recognized facts have led to the slogan, "The prevention of heart disease in children is the prevention of rheumatic infection." While this by and large is true and because the prevalence of rheumatic infection in childhood offers a ready means of attack, we wish to emphasize particularly in this paper some of the other common etiologic factors in infectious heart disease affecting both the child and the adult heart, and to point out the relative frequency of this occurrence; and finally that, as the rheumatic child is to be considered a potential heart patient, the child or adult who has just passed through many