A corn is an injury to the living horn of the foot. It is very common in horses’ feet, and a great number of cases of lameness are due to this trouble. Corns always appear in that part of the foot included in the angle between the bar and the wall of the foot at the heel.
In corns the sensitive laminae of the foot are bruised, the capillary blood vessels are ruptured, and a small amount of blood escapes permeating the horn in the immediate neighborhood, and staining it a dark red color. Of corns three kinds have been recognized: the suppurative, the moist and the dry corns. This division is based on the severity of the result which follows the primary cause.
The fore feet are almost exclusively subject to this disease, and I cannot remember of ever having seen a case of corns in the hind feet. In talking about corns with a veterinarian having a large practice, I asked him if he ever saw a case of corns in the hind feet. Meditating for a while, he answered, “I never did, sir.” This is not intended to disclaim the existence of corns in the hind feet. There probably are cases, but they are very rare. This fact should suggest something to a casual observer. Why are not the hind feet subject to corns as much as the fore feet? There are three reasons why they are not. First, the hind feet support less of the heft of the body; second, they receive more moisture and are not dried to the same extent as the fore feet; and third, the heel of the fore foot during progression is first placed on the ground, wherefore it receives more concussion than the heel of the hind foot, in which the toe strikes the ground first. These facts should give the clue of the causes of corns.
I do not believe there ever was a writer on this subject who did not attribute the cause of this disease to bad shoeing, and I would not be surprised to some day encounter a work which will settle the whole question of diseases in horses by the sweeping assertion that from toothache to glanders they are all caused by bad shoeing. I make the assertion that there is not a horseshoer in the United States so ignorant that he will nail a shoe to a foot with the shoe on the inside of the wall, but no horseshoer is responsible for the position of the shoe three onths after the shoe has been put on. It is true that there are ignorant horseshoers, but they are not as stupd as some of the writers claim, and it becomes tiresome to read so many unjust criticisms from would-be wiseacres about the ignorance of horseshoeing, for if their statements were in substance true, the world would begin to suspect that all these mechanics were fugitives from some insane asylums. We ought to grant them the sense of ordinary men, and I have found in my practice that if I employ a workman who is doing poor work, the customer will generally make remarks at once, and I hold that the horseshoers are just as sensible, as a class, as any other class of workmen. The horseshoers of the United States should be exculpated from such absurd charges. These charges are mostly made by veterinarians who have never learned the ABC of horseshoeing. I claim that corns are not caused by shoeing, for if they were, every horse that is shod would have them. Neither are they caused by shoes that are claimed to have been on too long, for if that were the case every farm horse would have corns, while it is a fact that farm horses are less subject to corns than other horses. Further, if shoes, good or bad, are the cause, why are the hind feet not equally affected? I have often shod farm horses in the fall and the owner has brought the same horses to my shop in the spring to have the shoes pulled off. I have watched such cases for many years, but failed to find any trace of corns, while horses that had never been shod would have corns. It often happens to horseshoers that horses are brought to be shod where the old shoes have been on so long that the shoes will be found imbedded somewhere in the sole, but there will be no corns, either at the time of the shoeing or later. The reason that the shoe cannot be the cause of corns is this: when a shoe has become imbedded in the foot in such a manner that it will hurt, the horse will at once go lame. The owner’s attention is called to it, and the first thing done is to remove the shoe, and the worst that could have happened is a light bruise, which will heal as soon as the cause is removed.
If there should be a horseshoer so ignorant (and I do not believe there is one) as to set the shoes inside of the wall, I will venture the assertion that the owner of the horse would not allow it. We will, therefore, be safe in dismissing that charge, and the damage done by the shoes, after they have been on for three months, should be credited to the owner of the animal so neglected.
In Sweden corns are called “stone bruise,” but I claim that stones are not the cause of corns either; for if a stone gets wedged in between the wall and the sensitive laminae so as to cause pain the horse will show it at once by limping on the injured foot. The foot will then be examined and the cause of the lameness discovered. The stone will then be removed, which also removes the cause, and effects the cure.
Corns are produced by something more obscure than stones and shoes, otherwise they would be more easily cured. Corns on the human foot are different from corns in horses; but there are cases where the corns in the horse assume the character of a callousness, and they cannot be cured, because the friction cannot be removed. Now then you may ask, what are corns? Corns are the result of a bruise, caused by the friction of the coffin and navicular bones against the sensitive laminae of the foot. The next question is, what causes this friction? First, hard driving on hard roads; second, contraction of the hoof, which causes the sensitive laminae to press against the sharp edges of the coffin and the navicular bones, bruising the sensitive laminae and resulting in corns. All talk of shoeing to cure corns is, therefore, vain. The fore foot being ore exposed to dryness, and receiving more of the heft of the animal, is more susceptible to corns. The center of gravity going at the inner side of the foot is the reason why corns, in most cases, are found on the inner side of the foot.