The basal cells of the epidermis and the contiguous portions of the true skin, or corium, contain pigment. In the skin of the dark races, the pigment lies in other layers as well. Recent methods of staining have shown that the pigment, or melanin, is not the only type present in and about the basal cells. Prepigment granules may be revealed by special staining methods. The chromatophores may likewise be demonstrated.
The white person's skin is not white normally. Its color depends on the presence of pigment, the contents of the blood vessels close to the surface and the thickness of the granular layer of the epidermis. The granules of the cells of the granular layer are highly refractile to light. Where the granular layer is absent, as in the lips and the nail-bed, the color is pink and not white. Where the granular layer is thick, as in a