Verrucae or Warts are of very common occurrence, and consist in a local enlargement or overgrowth of all the constituents of the skin. The horse is particularly liable to them; they appear in different positions, and frequently in parts which come in contact with the harness; but they are of still more frequent occurrence in parts of the skin which are absolutely free from all risk of pressure or friction, and this fact suggests that neither of these causes can have much to do with their production. On the eyelids, about the lips, on the inferior parts of the abdomen and the sheath, warts are common, and these parts are free from contact with the harness or pressure of any kind. Warts are of different forms, sometimes being diffused and scarcely raised above the surface, involving large portions of the skin. Another form is the ordinary pedunculated wart, which hangs from a pedicle or narrow neck; and there is also a lobulated form which projects from the skin and generally presents a red and sometimes bleeding surface.

Treatment of warts is essentially of a surgical character; the means adopted for their removal are various. The most summary method of removing them is by the use of the knife; a ligature in the case of pedunculated warts is also employed, and caustics are used for warts in any shape or in any position. A favourite compound is arsenic mixed into a paste with honey. The wart which is to be removed is scraped in the centre until slight bleeding occurs; to this spot the arsenical paste is applied, and the inflammation which follows ends in the sloughing of the whole growth; but unless the caustic preparation is employed very carefully, the destructive action of the arsenic will extend beyond the wart and serious loss of structure is likely to happen. When warts occur in positions where caustics could not safely be used, it is the practice of some to take the affected animal to a slaughter-house and dress the warts with the blood of a recently-killed animal. Two or three applications of this treatment are said to cause the growths to shrink and ultimately to fall off.