These are hard callous tubercles, insensible of themselves, but by pressing and bruising the adjacent fibres, they often become very painful, particularly when they hurt the fibres of the tendons, or the periosteum, that is the membrane that immediately covers the bone. When the blood-vessels are comprest by corns, the circulation through them will be slopt, whence arises redness, and sometime an inflammation. If one of these fine vessels burst, a drop or two of blood will be extravasated, and then it will corrupt and cause the corn to turn blackish, which forbodes an ulcer.

Sometimes corns are more painful in the evening, and against change of weather; because, at those times, the nervous fibres are more sretch'd by a fulness of the vessels, caused by a diminished perspiration, which is always less in the cool of the evening, than in the day time; as also when the air is moist, the weight of the atmosphere is grown less, and the air becomes less elastic, which is always the cafe before rain.

When the root of the corn penetrates to the tendons, or the periefleum, and strongly compresses them, or when they have received some blow, or are cut to the quick, it has often bad consequences, such as an inflammation, an abscess, a gangrene, or convulsions. When corns are superficial, and only lodged in the skin, they are easily cured. These need only be softened in warm water, and cut as near the root as possible; after which, a plaster must be applied, consisting of equal parts of the plaster of the mucilages, and that of ammoniac with mercury; or a small bit of the last alone will do of itself. Some use green wax, or a thin bit of lead rub'd over with quicksilver, or even simple diachylon alone. But, above all, care must be taken that the corn is not press'd by the shoe, or in any other manner.

Some have the art of drawing out a superficial corn, root and all. But if it adheres to a tendon, or to the Periostium, great care must be taken not to hurt those nervous parts. In this case you must only soften them for some time in warm water, and then pare off the surface, rubbing them afterwards with hot linseed oil, and laying a plaster of the mucilages over them. Those that use caustics, aqua fortis, or butter of antimony, often occasion terrible accidents. Some advise the cinnabar plaster of Bates, and recommend it from experience.