CORNEA, DISEASES OF.—See EYE, DISEASES OF.
CORNS.—Thickenings of the horny layer of the skin, forming circular or oval callosities over a joint, usually over the little toe. The painful ness of the corn distinguishes it from other callosities. It is not situated as a smooth, horny layer upon the underlying part ; but a vitreous, thickened plug descends in root form, often containing remnants of former hemor rhages as black granules. These solid plugs press upon nerve-branches, and are therefore extremely sensitive to pressure. Corns are often con fused with thickenings of mucous follicles over the ball of the big toe (bunions), which are of an inflammatory nature and lead to abscesses ; this happens rarely with corns unless an injury occurs when cutting them.
Corns are best treated with the aid of a 5o per cent. solution of potash lye, which should be plentifully applied to the corn before any attempt is made to loosen the plug. It is advisable to scrape off layer after layer with
a sharp knife rather than to cut, and to carefully loosen the last, innermost, horny substance with the point of the knife. In case of bleeding, lunar caustic or alum may be used. Great care must be taken to avoid infections. If such occur, and the toe becomes red and swollen, a physician should be consulted at once. A saturated solution of salicylic acid in collodion is a useful corn caustic. Its action is slow but effective, and not painful.
Corn-plaisters of caoutchouc, cotton, or leather, are merely preventives, and possess no curative value. Quacks and corn doctors have been responsi ble for the loss of many human lives by blood-poisoning, caused by lack of cleanliness in performing operations.