From a study of the literature it would seem that the sequence of bacterial endocarditis on a syphilitic endocarditis is a decided rarity, despite the frequency of the latter condition and the fact that the former infection often has a selective action on the aortic valve. No reason can be assigned for this, although the age incidence of the two diseases probably plays some part. Another factor may be the increased vascularity of the valve previously damaged by rheumatic fever as compared with that damaged by syphilis. A case is reported of an individual suffering from a typical syphilitic aortitis and aortic endocarditis. One year later the patient enters the hospital with a non-hemolytic streptococcic endocarditis, which pursues the usual course and terminates in death. At necropsy a characteristic syphilitic aortitis with involvement of the aortic ring is found, together with an acute verrucose endocarditis of all the aortic cusps and perforation of one, with an extension into one mitral leaflet.