CLINICAL HISTORY OF THE ACUTE FORM. The muscular mitral insufficiencies may present themselves in two forms: first, acute; second, chronic. The acute cases present themselves during the course of those diseases which affect the myocardium. These are diphtheria, scarlet fever, typhoid, acute articular rheumatism, and in general, the acute infections, the ones mentioned predominating. As I have seen them, the majority of the cases were in polyarthritis. During the course of the disease a systolic murmur, usually soft and blowing, will be heard in the region of the apex. At first it is often inconstant, but as the days go by it comes to be constant, always with its maximum of intensity at the apex, and seldom of great intensity. The heart presents the physical signs of a slight or moderate dilatation without hypertrophy. I have never seen extreme dilatation, never anything like enough to cause a mechanical and truly