Curved pieces of iron, made to fit accurately the horny hoofs of horses, to which they are nailed in a peculiar manner; the use of the shoes being to preserve the hoofs from the destructive effect that would take place by their collision and friction against the hard substances of which our common roads are formed. It is a common rule to make the shoes three times as thick at the toes as at the heels, so that by this means the frog (which is a central projection in the foot) may come down to the ground. The nails are all placed forward, four on each side, but not approaching too near the heels, and are countersunk in conical or wedge-shaped holes. For horses which go in shafts, or are used in hunting, it is usual to make shoes with only one heel, which should be outward. The horse's heel is rather lowered on that side, and the inner heel of the shoe somewhat thickened, so as to balance and bear equally. The best breadth for the shoe of a medium-sized horse is said to be one inch at the toe, and three quarters at the heel; the weight, about eighteen or twenty ounces.

In order to fit the shoe without causing the horse to stand too much on his heels, the under part of the crust, or wall of the hoof, is pared away to receive the excess of thickness in front; for the bottom of the shoe, it is generally conceived, ought to be perfectly flat, without any stubbings or calk-ings in front. Paring away the heels is a most destructive practice, except in case of absolute excrescence in those parts; nor should the bars (or diagonal ridges) that extend from the heels to the frog, or central projection, ever be cut more than is absolutely necessary for the purpose of keeping them in a clean and healthy state. A good open heel is the indication of a powerful foot; hence the sides of shoes ought not to be much contracted; when the heels are tender, what is called a bar-shoe ought to be applied. On the frog the horse chiefly depends for a spring or resistance at the bottom of the foot: if this part does not touch the ground, the whole motion will be derived from the upper parts of the limb, and a very uneasy gait will inevitably follow: this points out the propriety of leaving it fully at liberty to come in contact with the ground. Mr. Colman, the distinguished professor of the Veterinary College, says, that " no animal, nor any part of the animal, can be preserved in health, where the natural functions are perverted; and he strongly urges the necessity of some great alterations being made in the practice of shoeing horses, so that a portion of the weight of the animal may be sustained by the frog, which, from its central projection in the foot, and the tough elastic nature of its substance, was evidently designed for that purpose. In a recent paper on the same subject, from the pen of Mr. Cherry, that gentleman entirely coincides with the author just quoted, and considers that not only the frog, but the sole also, (which is that horny portion of the foot between the frog and the exterior wall or crust of the hoof,) should be made to sustain its proportion of the superincumbent weight; and, he adds, that any treatment which deprives these parts of pressure, must, according to true physiological principles, induce disease. It is evident that a horse in a state of nature presses with the whole surface of his foot upon the ground, the rim of the hoof, by its angular projection, preventing slipping, and the frog serving as a cushion to prevent any ill effects from violent concussion.

By the ordinary mode of shoeing, however, the whole weight of the horse is thrown upon this angular rim, or wall of the hoof, contrary to the designs of Providence, and the plainest dictates of common sense; for, being shod with a thick bar of iron on this part, the foot is thereby lifted up, forming a hollow cavity within the shoe, which, as Mr. Cherry says, "deprives the foot of that support which it would otherwise receive from the earth, and greatly deranges the mechanism of the whole foot." The same author proceeds to observe, that the feet of farm horses, though usually in that condition termed a state of neglect, will, upon examination, be found generally "moist, cool, and healthy; while a foot kept clean, is dry, brittle, and full of cracks;" which is evidently owing to the shoes of the former being usually clogged with earth, by which the whole surface of the foot is made to sustain the pressure, instead of the mere rim; the earth likewise contributes to the healthful condition of the feet by a supply of moisture for absorption. " Perhaps," Mr. Cherry continues, " it may be possible to prepare some compressible and adhesive substance to fill up the cavity after the shoe is on, which shall give support to the whole foot, yet without impeding the full action of its elastic properties."

The late Mr. Robert Dickenson entertaining the same views of the subject as the above-mentioned eminent authorities, took out a patent for some improvements in horse-shoes, of which the following is a description. In the annexed engraving, Fig. 1 exhibits a plan, and Fig. 2 a side view of the improved shoe as fitted on to the foot. Fig. 3 represents the ordinary English mode of shoeing, which has been here introduced merely by way of contrast. By Mr. Dickenson's plan, a piece of stout leather is cut to cover the whole under surface of the hoof; and on this is rivetted a plate of iron of a shape and magnitude to cover the frog, which it is designed to protect against injury in travelling upon hard stony roads ; under the leather covering is stuffed into the hollow of the hoof a quantity of sponge, and the shoe being nailed on through the leather, the whole is thus simply and permanently secured until the iron shoe is worn out, the leather lasting out several iron shoes, owing to it3 compressible elastic nature. The absorbent nature of the sponge keeps the foot always moist, and the whole surface of it is brought to sustain the pressure. It will be observed that the iron rim of Mr. Dickenson's shoe is curved after the French manner, as shown in Fig. 2.