[Illustration:  FIG. 93.—­Callosities and Corns on the Sole and Plantar Aspect of the Toes in a woman who was also the subject of flat-foot.]

#Corns.#—­A corn is a localised overgrowth of the horny layer of the epidermis, which grows downwards, pressing upon and displacing the sensitive papillae of the corium.  Corns are due to the friction and pressure of ill-fitting boots, and are met with chiefly on the toes and sole of the foot.  A corn is usually hard, dry, and white; but it may be sodden from moisture, as in “soft corns” between the toes.  A bursa may form beneath a corn, and if inflamed constitutes one form of bunion.  When suppuration takes place in relation to a corn, there is great pain and disability, and it may prove the starting-point of lymphangitis.

The treatment consists in the wearing of properly fitting boots and stockings, and, if the symptoms persist, the corn should be removed.  This is done after the manner of chiropodists by digging out the corn with a suitably shaped knife.  A more radical procedure is to excise, under local anaesthesia, the portion of skin containing the corn and the underlying bursa.  The majority of so-called corn solvents consist of a solution of salicylic acid in collodion; if this is painted on daily, the epidermis dies and can then be pared away.  The unskilful paring of corns may determine the occurrence of senile gangrene in those who are predisposed to it by disease of the arteries.

[Illustration:  FIG. 94.—­Ulcerated Chilblains on Fingers of a Child.]

#Chilblains.#—­Chilblain or erythema pernio is a vascular disturbance resulting from the alternate action of cold and heat on the distal parts of the body.  Chilblains are met with chiefly on the fingers and toes in children and anaemic girls.  In the mild form there is a sensation of burning and itching, the part becomes swollen, of a dusky red colour, and the skin is tense and shiny.  In more severe cases the burning and itching are attended with pain, and the skin becomes of a violet or wine-red colour.  There is a third degree, closely approaching frost-bite, in which the skin tends to blister and give way, leaving an indolent raw surface popularly known as a “broken chilblain.”

Those liable to chilblains should take open-air exercise, nourishing food, cod-liver oil, and tonics.  Woollen stockings and gloves should be worn in cold weather, and sudden changes of temperature avoided.  The symptoms may be relieved by ichthyol ointment, glycerin and belladonna, or a mixture of Venice turpentine, castor oil, and collodion applied on lint which is wrapped round the toe.  Another favourite application is one of equal parts of tincture of capsicum and compound liniment of camphor, painted over the area night and morning.  Balsam of Peru or resin ointment spread on gauze should be applied to broken chilblains.  The most effective treatment is Bier’s bandage applied for about six hours twice daily; it can be worn while the patient is following his occupation; in chronic cases this may be supplemented with hot-air baths.