PERICARDIUM, a conical membra nous sac containing the heart and the commencement of the great vessels, to the extent of about two inches from their origin. It is placed with its apex up ward behind the sternum in the interval between the pleurm—the serous sacs in which the lungs are inclosed; while its base is attached to the diaphragm. It is a fibro-serous membrane, consisting of an external fibrous and an internal se rous layer. The outer layer is a strong, dense, fibrous membrane; the serous layer invests the heart, and is then re flected on the inner surface of the fibrous layer. Like all serous membranes, it is a closed sac; its inner surface is smooth and glistening, and secretes a thin fluid which serves to facilitate the natural movements of the heart. It is inflam mation of this serous sac which consti tutes the disease that is known as peri carditis.
Pericarditis is a disease which occa sionally runs a very rapid course, and terminates fatally in 48 hours or less. In ordinary cases, however, which ter minate in apparent recovery, the disease generally begins to yield in a week or 10 days, and excepting that adhesion may remain, the cure appears to be complete in three weeks or less.
The treatment of pericarditis at pres ent in favor is much less active than when bleeding, mercurialization, etc., were considered necessary. Complete rest in bed, light diet, with opium or other sedatives as required; general med ication suited to the disease with which the pericarditis is associated, local ap plication of poultices or cotton wool, sometimes of leeches or blisters, are the chief measures employed.