The quantity of horn to be removed in order to leave the proper degree of thickness will vary with different feet. From the strong foot a great deal must be taken. From the concave foot the horn may be removed until the sole will yield to a moderate pressure. From the flat foot little need be pared; while the pumiced foot will spare nothing but the ragged parts.
The paring being nearly completed, the knife and the rasp of the smith must be a little watched, or he will reduce the crust to a level with the sole, and thus endanger the bruising of the sole by its pressure on the edge of the seating. The crust should be reduced to a perfect level all round, but left a little higher than the sole.
The heels will require very considerable attention. From the stress which is thrown on the inner heel, and from the weakness of the quarter there, it usually wears considerably faster than the outer one; and if an equal portion of horn were pared from it, it would be left lower than the outer heel. The smith should, therefore, accommodate his paring to the comparative wear of the heels, and be very careful to leave them precisely level.
If the reader will recollect what we have said of the intention and action of the bars, he will readily perceive that the smith should be checked in his almost universal fondness for opening the heels, or, more truly, removing that which is the main impediment to contraction. That portion of the heels between the inflection of the bar and the frog should scarcely be touched, at least nothing but the ragged and detached parts should be cut away. The foot may not look so pretty, but it will last longer without contraction.
The bar likewise should be left fully prominent, not only at its first inflection, but as it runs down the side of the frog. The heel of our shoe is designed to rest partly on the heel of the foot, and partly on the bar, for reasons that have been already stated. If the bar is weak, the growth of it should be encouraged, and it should be scarcely touched at the shoeing until it has attained a level with the crust. We recal to the recollection of our readers the observation which we have before made, that the destruction of the bars not only leads to contraction by removing a powerful impediment to it, but by adding a still more powerful cause in the slanting direction which is given to the bearing at the heels, when the bar does not contribute to the support of the weight.
It will also be apparent that the horn between the crust and the bar should be carefully pared out. Every horseman has observed the relief which is given to the animal lame with corns when this angle is well thinned; a relief, however, which is but temporary, for when the horn grows again and the shoe presses upon it, the torture of the animal is renewed.
The degree of paring to which the frog must be subjected will depend on its prominence, and on the shape of the foot. The principle has already been stated, that it must be left so far projecting and prominent, that it shall be just within and above the lower surface of the shoe, it will then descend with the sole sufficiently to discharge the functions which we have attributed to it. If it be lower it will be bruised and injured; if it be higher it cannot come in contact with the ground, and thus be enabled to do its duty. The ragged parts must be removed, and especially those occasioned by thrush, but the degree of paring must depend entirely on this principle.
It appears, then, that the office of the smith requires some skill and judgment in order to be properly discharged; and the horse proprietor will find it his interest occasionally to visit the forge and complain of the careless, or idle, or obstinate, and reward, by some trifling gratuity, the expert and diligent. He should likewise remember that a great deal more depends on the paring out of the foot than on the construction of the shoe; that few shoes, except they press upon the sole, or are made outrageously bad, will lame the horse; but that he may be very easily lamed from ignorant and improper paring out of the foot.
The putting on of the Shoe.—The foot being thus prepared, the smith looks about for a shoe. He should select one that as nearly as possible fits the foot, or may be altered to the foot. He will sometimes care little about this, for he can easily alter the foot to the shoe. The toe-knife is a very convenient instrument for him, and plenty of horn can be struck off with it, or removed by the rasp, to make the foot as small as the shoe; while he cares little, although by this destructive method the crust is materially thinned where it should receive the nail, and the danger of puncture is increased, and the danger of pressure upon the sole is increased, and a foot so artificially diminished in size will soon grow over the shoe, to the hazard of considerable or permanent lameness.
While choosing the shoe we must once more refer to the shape of our pattern shoe; the web is of equal thickness from toe to heel. A shoe, thinner at the heel than at the toe, by letting down the heel too low, is apt to produce sprain of the flexor tendon, and a shoe thicker at the heels than at the toe is fit only to elevate the frog, to the destruction of its function, and to its own certain disease, and also to press upon and to batter and to bruise that part of the foot which is soonest and most destructively injured.