DISEASES OF THE SKIN.
The skin is divided into three layers. Beginning with the outer one and naming inward, they are named as follows: The outer layer is called the epidermis or cuticle (near or upon the skin). The second layer is called the corium, derma cutis vera, or true skin. The third layer is called the sub-cutaneous (under the skin) (fatty or connective) tissue. This last layer contains the sweat glands, the lower end of the deep-seated hair follicles, (little sacs containing the roots of the hair) and larger branches of the lymphatics, blood vessels and nerves, and serves in general as a bed for the true skin to rest upon, and by which the true skin is connected with the deeper parts, muscles, etc. The appendages of the skin are the hair, nails, sebaceous and sweat-glands. The discharge from the sweat-glands form a little or larger tumor. The contents of a wen are from sebaceous glands—fat secretions—fat tumor. The following names are frequently mentioned in the skin diseases:
Macule. (Spots, patches). Skin is altered in color, but the skin is not raised or depressed; freckle, etc.
Papule. (Pimple). Elevated piece of skin, varying in size from a pin-head to a coffee bean.
Tubercle. (Node-lump). A solid elevation of the skin, varying in size from a pea to a cherry.
Tumors. These are soft or firm elevations of the skin, like a wen or hard lump. They are always deep-seated.
Wheel. A round flat, white or pink elevation of the skin; such as hives, mosquito bites, etc.
Vesicle. This is a pin-head or pea-sized elevation of the outer layer (epidermis) filled with a watery fluid.
Bleb. (Bulla). A circumscribed elevation of the skin and contains a watery fluid, such as a burn, etc.
Pustule. A rounded elevation of the outer layer (epidermis) of varying size, containing pus (matter).