NAILS, DISEASES OF.—The nails, like the hair, being developed from t he skin, it is obvious that a number of diseases affecting the skin may affect the hair and the nails also. This is particularly true of the nails, owing to their peculiar anatomical structure. The greater portion of a nail is cornitied and, like a foreign body, the nail mechanically aggravates existing affections of those portions of the skin situated underneath it, debarring them from the action of healing remedies. Suppurations of the nail-beds arc, therefore, very difficult to treat, and often do not heal until after the nail has either been removed or cast off spontaneously. At the very beginning of a throbbing pain at the root of a nail one should, therefore, consult a physician, in order that an effort may be made to overcome the infection.
When a splinter has entered beneath a nail, and cannot be removed, the superficial layers of that part of the nail which covers the splinter should be softened by the application of a 5o per cent. potash-lye, and then scraped with a sharp knife until the entire splinter is laid bare, when it can be readily removed. It is best, however, to have a physician attend to this treatment.
Infection by Fungi often causes a peculiar, rough-streaked transformation and deformity of the nails (see Fig. 2qo), the treatment of which requires great attention. Such proliferations of fungi may cause the complete loss
of a nail, such as is noted also in some general affections (syphilis), with softening and ulcer formation. A badly healing ulcer of a nail, accompanied with a doughy, vitreous thickening of the entire finger, presenting that ulcers and warty crust formations, and which for months is refractory to treatment, is also inVariably a sign of syphilis of the nails, and is often rapidly cured by the internal or external employment of mercury.
White spots frequently develop in the nails (see Fig. 291). These owe their existence to air that entered during the growth of the nail, and is confined there. A white, crescent-shaped mark at the root of a nail is considered a sign of beauty. An injury to a nail causes tne exuded blood to shine through the nail with a bluish colour, only the crescent retaining its white appearance.
The growth of nails in places other than at the ends of the digits (on the ides of the fingers, on the back. or on the neck) is an extremely rare abnor mality. A so-called " griffin-claw " is of more frequent occurrence, especially on the feet, when the nails have not been properly attended to. The nail develops into an unevenly raised claw, resembling the bill of a parrot.