This is an inflammation of the internal lining of the heart. There is at first pain about the heart, whose disordered action may be violent, or else feeble irregular, and intermitting. There is more or less difficulty of breathing, and the organ gives forth some abnormal sounds, such as the bellows murmur, the rasping and sawing murmur, arising from thickening of, or deposit on, some of the valves. One or more of the above symptoms occurring during the course of acute rheumatism, may be considered a sign of endocarditis. The patient generally lies on his back, and his pain may sometimes be so slight as scarcely to be noticed, but in dangerous cases there is extreme anguish, liable to be followed by orthopnoea, or necessity of being in the erect posture to be able to breathe, followed by restlessness, delirium, and death. The murmurs may occur at any stage of the disease from the very beginning towards the close.

TREATMENT. -- The treatment is essentially the same as for pericarditis in the commencement of the attack, with the exception that it may be necessary to administer stimulants in some cases. Leeches may be applied to the cardiac region, and between the shoulders. Digitalis and veratrum should be cautiously administered to control the heart's action. If associated with rheumatism, colchicum should be given. Mustard poultices, blisters or hot packs may be applied to the chest to hasten the absorption of the deposit of lymph.

If myocarditis, or inflammation of the entire substance of the heart, complicates either pericarditis or endocarditis, the active treatment advised in the latter diseases will remove it.