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660 splitting in a radiating fashion. Pressure being thus removed, the yaw fungates, and suffering diminishes.

A cracked, scaly condition of the hands and feet, sometimes persisting for years, is not unusual in negroes, and must not be confounded with yaws, although not infrequently the two conditions coexist.* Distribution.— The yaws may be scattered over the whole body; or the crop may be limited to one or two growths; or they may be confined to a circumscribed region of the skin. They are commonest on exposed parts, on the anterior surface of the body, and on parts especially liable to injury, as the feet and legs. They are most frequently found on the lower extremities; rarely on the scalp, and still more rarely in the axillæ. They are hardly ever seen on mucous surfaces unless about the lips, around the angles of the mouth, and in the nostrils, where they often form clusters.

Duration and recurrences.— Yaws lasts for weeks, or months, or years, its duration depending on the general health, idiosyncrasy, hygienic conditions, and the treatment employed. Mild cases in healthy subjects finish in about six weeks. In other instances, especially in the debilitated, the disease runs on for months, successive crops of eruption being evolved. Sometimes these recurrences may stop short at the stage of desquamation, or at the papular stage, or