Bone-Spavin, is a bony excrescence, or hard swelling, on the inside of a hone's leg. A spavin which begins on the lower part of the hock, is not so dangerous as that which grows higher, between the two round processes of the leg-bone ; and that which appears near the edge, is less injurious than if it were situated more towards the middle and inwards, where it would, in a greater degree, impede the bending of the knee.

A swelling occasioned by a kick or blow, is not at first the true spavin, nor so dangerous as when it proceeds from a natural cause ; and that which grows on the leg of a colt, is not so inveterate as that of a horse come to maturity. In old horses, the spavin generally is incurable.

The usual method of treating this disease is, by blisters, and the actual cautery. When a fullnes.3 on the fore part of the hock is occasioned by hard riding, or any other violence, cooling and repelling applications are proper, as in the case of bruises or strains.

Among the various prescriptions for the blistering ointment, the fol lowing, by Mr. Gibson, is preferable; able: Nerve and marsh-mallow ointment, of each two ounces ; quick-silver, one ounce, thoroughly mingled with one ounce of Venice turpentine ; Spanish flies, powdered, a dram and a half ; sublimate, one dram ; oil of origanum, two drams.

When the hair is cut as close as possible, the ointment is to be applied pretty thick to the injured part, in the morning, and the horse should be kept tied up without any litter till night. He should then be untied, that he may lie down, and a pitch plaster fastened to the part, with a proper bandage.

After the blister has done running, and the scabs begin to peel off, another may be applied, which will have a still better effect; and in young horses, will generally complete the cure. But if the spavin has been of long standing, a repetition of the blister rive or six times, will perhaps be requisite. Each application must be made at intervals of a fortnight or three weeks, lest the blemish of a sear, or baldness, remain on the part.

Spavins on old or full-aged horses, as they grow more inward, and run among the sinuosities of the joint, are, for the most part, incurable.

In such cases, the strongest caustic blisters must be applied, or the part immediately fired; but the best and safest way to preserve the use of the limb is, by long-repeated applications of the above-mentioned blistering ointment, for some months, if necessary. The horse, in the intervals, should be exercised moderately; and by degrees the hardness will be dissolved, and disappear.

If the spavin is deep, and runs so far into the joint that no applicatio; can reach it, all medicines will be unavailing. When the disease does not penetrate the joint, and the blistering method is found ineffectual, the swelling may be safely cauterized with a thin iron, forced pretty deeply into the sub-stance ; and it should afterwards be dressed according to the foregoing directions.