This investigation comprises a study of venous pulse, carotid, cardiographic, and heart sound records from twenty-one men with normal hearts. The heart sounds were recorded by the method of Einthoven. When correction is made for transmission, the first heart sound begins, on an average, 0.131 of a second before the c-wave of the venous pulse, and has an average duration of 0.128 of a second. Th...