Domestic Encyclopædia (1802)/Nails, in Anatomy

NAILS, in anatomy, are horny lamina or plates growing over the ends of the fingers and toes of men, as likewise over the lower extremities of the inferior animals.

The nails apparently possess similar properties with the epidermis, or outward skin, being devoid of sensation; and, if the latter membrane be separated from the true skin, by any accident, the nails are likewise in danger of being removed, or materially injured.

These excrescences are divided into three parts, namely, the root, the body, or middle, and the extremity, or end. The root is a soft, thin, white substance, which terminates in the form of a crescent, and to which the epidermis strongly adheres: from this part, the nails increase, and derive all their nourishment. The body, or middle, is considerably broader, thicker, and of a deeper red than the root; while the extremity is of still greater firmness.

The use of the nails, in animal economy, is to defend and cover the nervous warts or papillae of the toes and fingers from external injury, when they come in contact with rugged bodies. Hence, though cleanliness require them to be occasionally cut, that operation ought not to be carried too far; because the sense of feeling would thus be impaired and diminished: on the other hand, they should not be suffered to grow to a considerable length; as the impurities collecting beneath them not only present a slovenly picture, but such neglect also renders the nails liable to be split and broken by various accidents.