=Overreach= is confined to fast horses; it happens to those which are good steppers. When tired, the feet are apt to be moved irregularly; thus, one foot is often in its place before the other has been lifted; the result is, that the inner part of the hind foot strikes the outer side of the fore coronet. A wound, and frequently a severe one, is the consequence. False quarter or quittor is likely to ensue; the treatment must be the same as was before described. No poultices are required; these only add to the weight of the injured limb, and augment the distress of the animal. No harsh measures should be allowed; the horse has enough to bear; a slough has to take place. This is a severe tax upon the strength; all the good food and prepared water the animal can consume will not now be thrown away; the treatment is materially shortened by the nourishment being sustaining of its kind, and liberal in quantity; but the injury should be treated only with the knife, and the chloride of zinc lotion described in the course of this article. CORNS. =Corns= are of four kinds--the old, the new, the sappy, and the suppurating; all are caused by bruises to the sensitive sole. The shoe is the passive agent in their production, when they occur in large, fleshy feet; the thick, unyielding, horny sole is the passive agent, when they are present in contracted feet. The coffin-bone, in both cases, is the active agent; the wings, or posterior portions of this bone, project backward nearly as far as the bars, or immediately over the seat of corn. When the horse is in motion, the coffin-bone can never remain still; it rises, or rather the wings are drawn upward by the flexor tendon, every time the foot is lifted from the earth, and sinks, because of the weight cast upon it, every time the foot touches the ground. The wings of the bone, thus in constant action, when the horny sole is weak, often descend upon the fleshy sole, and bruise that substance upon the iron shoe; what is called a corn is the consequence. In contracted feet, where the sole is high, thick, and resistant, the horny sole does not descend, even when the immense weight of the horse's body rests upon it. It remains firm and fixed during every action of the animal--not so, however, the coffin-bone, which is in continuous motion. The result, of course, is, the imposed burden forces the wings of the coffin-bone downward. The horny sole will not yield, and the fleshy sole is therefore bruised between the wings of the coffin-bone and the horn bottom of the hoof; a corn is thereby established. [Illustration: DIAGRAM Showing the position of the hindermost part of the coffin-bone when in a passive state; also portraying the shoe in the fleshy or flat foot. ] [Illustration: DIAGRAM Illustrating the relative positions of the wings of the coffin-bone, and the thick, concave, horny sole of the contracted foot when not in motion. ]