When one considers that there are no set rules for the diagnosis of rheumatic endocarditis, one can readily understand why some 50 per cent of cases are referred to one of our heart clinics with a diagnosis of mitral insufficiency, rheumatic heart disease, rheumatic endocarditis, and so on. This point is well brought out by Paul B. White, who analyzed 2,300 such cases in 1927. He shows that the ratio of apical systolic murmurs, transmitted and not transmitted, was 1 to 20. He concludes that the murmurs originating at the apex, if systolic, may or may not be important. The diastolic murmurs, however, are always important. White, in his article, emphasizes the necessity of mechanical measures in diagnosing some borderline cases. Mindful of these and other difficulties attendant on the diagnosis of rheumatic heart disease, I undertook, about eight months ago, a study of a selected group of patients under