_Corns_ are occasioned by the inflexible shoe pressing on that part of the sole, or possibly from friction of the bones upon its internal surface. They present the appearance of a red effused bruise, almost invariably situated on the heel of the sole of the inside quarter of the fore feet.—_See_ illustration, fig. 3, page 130.
When neglected, they occasion severe lameness, and go on to suppuration.
Broken knees are also frequently the result of neglected corns.
A horse that is habitually properly shod is never likely to have a corn. It arises entirely from want of attention and judgment in the smith. The groom, who should always stand by when a horse is shoeing, ought to be instructed to see that the farrier with his drawing-knife invariably pares out the sole at the seat of corn; it can be no injury whatever to the foot when properly done, and is the best preventive of corns. Also take proper care that the shoes are so put on that they cannot by possibility press upon the sole.
For prevention, keep the seat of corn well pared away, and dress with tar, unless in the suppurating state, when it requires poultices (page 160), and the ordinary treatment for that state, and full rest.
_Over-reach_ or _Tread_ proceeds from the shoe of one foot coming in contact with the soft or sensible part above the hoof of the other. As the parts likely to be affected round the coronet are full of vessels, the simplest remedial means are the safest—viz., water-dressing (page 160) in the first instance, and afterwards chloride of zinc lotion (one grain to the ounce of water), or glycerine.
_Broken Knees._—Most travellers on the road know what style of thing this is, so it is needless to describe it.
In bad cases, where the bones are exposed, and there is any appearance of synovia or joint-oil, place the horse in the nearest convenient stable, and leave him there to be attended to by a professional man as soon as possible. When the abrasion is merely superficial, take the animal quietly to his stable, if near.
In any event, wash the wound with warm water, which, if it be at all deep, should be done by squeezing the water _above_ the wound, and allowing it to run down, as this part of the leg is very delicate and sensitive, and rough handling with a cloth or sponge should be avoided.