Note:  Do not rely on this information. It is very old.

Nail

Nail, a horny growth consisting of modified epithelial cells; it rests upon a bed of skin, which is called the matrix of the nail, and the cells of this matrix are in a condition of active growth (reproduction and transformation), by which the body of the nail is continually renewed, the formation of fresh horny tissue taking place from beneath and behind, so that the nail gradually grows forward and projects beyond the tips of the fingers and toes.