The abnormalities included in this group are functional or organic in nature; the latter when there is an anatomical change, the former when qualitative or quantitative changes exist. Naturally a number of these diseases could be grouped elsewhere, but simplicity demands their retention in this class which is subdivided into: 1. Diseases of the sweat-glands. 2. Diseases of the sebaceous glands. 3. Diseases of the hair and the hair-follicles. 4. Diseases of the nails.