=The dermis=, or inner layer, is a closely woven sheet of _connective tissue_ (colored Fig. 1) containing a great number of _sweat_ and _oil glands_, _roots of hairs_, _blood vessels_, _absorbent vessels_ (lymphatics), and _nerves_ (colored Fig. 1). The dermis is sometimes called the true skin because it is of greater importance than the epidermis. It is united loosely to the underlying organs by a layer of connective tissue. It is in this layer that fat is stored. The upper surface of the dermis rises into a multitude of projections (see colored Fig. 1) called _papil′læ_ (singular, papilla). The epidermis fits closely over them and completely levels up the spaces between them except on the palms and the soles. Here the papillæ are in rows, and there is a fine ridge in the skin above each row of papillæ (Fig. 24). In the papillæ are small loops of blood vessels and sometimes a nerve fiber (colored Fig. 1). [Illustration: FIG. 20.--EPIDERMIS OF ETHIOPIAN.] [Illustration: FIG. 21.--EPIDERMIS OF CAUCASIAN.] =The epidermis= _is composed of a mass of cells_ held together by a cement resembling the white of an egg. The cells near the surface are hard and flattened; those deeper down near the dermis are round and soft (see Fig. 21). These cells are living cells. They are kept alive by the nourishment in the watery portion of the blood which soaks through from the blood tubes in the neighboring papillæ. Hence these cells are growing cells; they subdivide when they reach a certain size, and replace those wearing away at the surface, thus constantly repairing the epidermis. The dry outer cells wear away rapidly. They have no nuclei and are dead cells. The new cells forming beneath push them so far away from the dermis that nourishment no longer reaches them, and they die. =Pigment.=--The cells in the lower layers of the epidermis contain grains of coloring matter, or pigment. All other cells of the epidermis are transparent; the pigment has the function of absorbing and arresting light. Albinos or animals entirely without pigment have pallid skins and pink eyes (Exp. 1). =Immigrants from a Cloudy to a Sunny Climate. Adaptation.=--The cells of the deeper tissues can readily be exhausted by the stimulation of too much light. The sunnier the climate, the greater the need of pigment; hence the dark skin of the negro and the blonde skin and hair of the Norwegian. European immigrants to sunny America will grow darker. The Indian’s skin is better suited to our climate than is a fair skin. Brunettes have a better chance for adaptation than blondes. The American type when developed will doubtless be brunette. =The hair= grows from a pit or follicle (Fig. 22). _Blood vessels and a nerve fiber go to the root_ or bulb from which a hair grows. The hair will grow until this papilla, or bulb, is destroyed (Exp. 2). [Illustration: FIG. 22.--DEVELOPMENT OF A HAIR AND TWO OIL GLANDS.]