Corn, a hard, circumscribed tumor, formed of thickened cuticle, situated generally on the feet, on the joints, or between the toes, and sometimes in the sole of the foot; but it may be formed over any projecting bony point subjected to frequent pressure or friction. It is hardly necessary to state that the usual cause of corns is the pressure of tight boots and shoes, or the friction of loose and unyielding ones. The common hard corn is simply a series of epidermic unorganized laminae; the soft corn, such as is usually found between the toes, is more properly a fungous, irritable growth from the true skin, extending often through the dermis to tendons, ligaments, and even to the periosteum. According to Sir Benjamin Brodie, when a corn is completely formed, there is a minute bursa between it and the true skin, to prevent injury to the subjacent parts. In damp weather corns swell, like all hygrometric bodies; the pain they cause is not in the corn itself, but in the parts compressed by it, and this, as most persons know, may be very severe. That pressure is the cause of these growths is evident from the fact that they do not occur in persons who go barefooted, nor on the hands.
To get rid of corns, the first requisite is to avoid the constantly acting cause of a too tight or ill-fitting shoe. The hard corn may generally be removed by the action of warm water, or softening liniments, assisted by a needle, blunt knife, or file of steel or pumice stone. The deep varieties require extirpation by the needle or knife, or by various plasters and caustics. The nostrums advertised for their relief are in general worse than useless. Many devices are in use by sufferers to relieve the pressure on corns which they dare not have extirpated; as pieces of soft leather or cloth pierced in the centre, and smeared with emollient and narcotic ointments. The operation for their removal is painless, bloodless, and of short duration, and effectual if the exciting causes be avoided.