This ailment occurs sometimes in the fore feet, but oftener in the hind feet; and though neither contagious nor epizootic, it not unfrequently appears about one time or within a brief period, on most or all of the horses in a stable. It essentially consists in a stoppage of the normal secretions of the skin, which is beneficially provided for maintaining a soft condition of the skin of the heel, and preventing chapping and excoriation; and it usually develops itself in redness, dryness, and scurfiness of the skin; but in bad or prolonged cases, it is accompanied with deep cracks, an ichorous discharge, more or less lameness, and even great ulceration, and considerable fungus growth; and in the worst cases it spreads athwart all the heel, extends on the fetlock, or ascends the leg, and is accompanied with extensive swelling and a general oozing discharge, of a peculiar strong, disagreeable odor.

Most of the causes of grease are referable to bad management, especially in regard to great and sudden changes in the exterior temperature of the heels. The feet of the horse may be alternately heated by the bedding and cooled by draft from the open stable door; or they may first be made hot and sensitive by the irritating action of the urine and filth on the stable floor, and then violently reacted on by the cold breezes of the open air, or they may be moist and reeking when the horse is led out to work, and then chilled for a long period by the slow evaporation of the moisture from them amid the clods and soil of the field; or they may be warm and even perspiring with the labor of the day, and next plunged into a stream or washed with cold water, and then allowed to dry partly in the open air and partly in the stable; and in many of these ways, or of any others which occasion sudden changes of temperature in the heels, especially when those changes are accompanied or aggravated by the irritating action of filth, grease is exceedingly liable to be induced. Want of exercise, high feeding, and whatever tends to accumulate or to stagnate the normal greasy secretion in the skin of the heels, also operate, in some degree, as causes. By mere good management and by avoiding these known causes, horse owners might prevent the appearance of this disease altogether.

In the early, dry, scurfy stage of grease, the heels may be well cleaned with soft soap and water, and afterwards thoroughly dried, and then treated with a dilution of Goulard's extract—one part to eight parts of water, or one part with six parts of lard oil. In the mildest form of the stage of cracks and ichorous discharge, after cleansing, some drying powder, such as equal quantities of white lead and putty (impure protoxide of zinc), may be applied, or simply the mixture of Goulard's extract with lard oil may be continued. In the virulent form of cracks, accompanied with ulceration, the heels ought to be daily washed clean with warm water, and afterwards bathed with a mild astringent lotion, and every morning and evening thinly poulticed or coated with carbolized ointment; and the whole system ought to be acted on by alteratives, by nightly bran mash, and, if the animal be in full condition, with a dose of purgative medicine. In the worst and most extensively spread cases, poultices of a very cooling kind, particularly poultices of scraped carrots or scraped turnips, ought to be used day and night, both for the sake of their own action, and as preparatives to the action of the astringent application; and the whole course of treatment ought to aim at the abatement of the inflammatory action, previous to the stopping of the discharge. Nothing tends so much to prevent grease and swelling of the legs as frequent hand rubbing and cleansing the heels carefully as soon as a horse comes in from exercise or work. In inveterate cases of grease, where the disease appears to have become habitual, in some degree, a run at grass, when in season, is the only remedy. If a dry paddock is available, where a horse can be sheltered in bad weather, it will be found extremely convenient; as in such circumstances, he may perform his usual labor, and at the same time be kept free from the complaint.