NEW THORACIC MURMURS, WITH TWO NEW INSTRUMENTS, THE REFRACTOSCOPE AND THE PARTIAL STETHOSCOPE.

1. An understanding of the physics of sound is essential for a better comprehension of refined auscultation, tone analysis, and the use of these instruments. 2. The detection of variations of the third heart sound should prove a valuable aid in predicting mitral disease. 3. The variations of the outflow sound should prove a valuable aid in determining early aortic lesions with the type of accompanying intimal changes. 4. The character of chamber timbre as distinct from loudness heard as the first and second heart sounds denotes more often the condition of heart muscle, and must not be confounded with valvular disease. 5. The full significance of sound shadows is uncertain. Cardiac sound shadows appear normally in the right axilla and below the left clavicle. Their mode of production is quite clear. 6. Both the third heart sound and the outflow sound may be heard with the ordinary stethoscope.