Chapter 50

The list from which a selection may be made comprises wood tar, gas tar, petroleum, creosote, phenic acid; sulphates of iron, copper, and zinc; chlorid of zinc, bichlorid of mercury, calomel, caustic soda, nitrate of silver, chlorid of lime; carbolic, nitric, and sulphuric acids.

In practice I prefer to give the newly shod foot a bath for an hour or two in a solution of the sulphate of iron made by adding 2 ounces of the powdered sulphate to a gallon of cold water. When the foot is removed from the bath it is dressed with oakum balls dipped in a mixture made of Barbados tar 1 part, oil of turpentine 8 parts, to which is slowly added 2 parts of sulphuric acid, and the mixture well stirred and cooled. The diseased parts being well covered with the balls, a pad of oakum sufficiently thick to cause considerable pressure is placed over them, and all are held in place by pieces of heavy tin fitted to slip under the shoe. The whole foot is now incased in a boot or folded gunny sack and the patient turned into a loose, dry box. The dressings are to be changed daily or even twice a day at first. When they are removed, all pieces of new horny matter which are now firmly adherent must be rubbed off with the finger or a tent of oakum. As the secretion diminishes, dry powders, such as calomel, sulphates of iron, copper, etc., may prove of most advantage. The sulphates should not be used pure, but are to be mixed with powdered animal charcoal in the proportion of one of the former to eight or ten of the latter. When the soft tissues are all horned over, the dressings should be continued for a time, weak solutions being used to prevent a recurrence of the disease. If the patient is run down in condition, bitter tonics, such as gentian, may be given in 2-dram doses twice a day and a liberal diet of grain allowed.

CORNS.

A corn is an injury to the living horn of the foot, involving the soft tissues beneath, whereby the capillary blood vessels are ruptured and a small quantity of blood escapes which, by permeating the horn in the immediate neighborhood, stains it a dark color. If the injury is continuously repeated, the horn becomes altered in character and the soft tissues may suppurate or a horny tumor develop. Corns always appear in the sole in the angle between the bar and the outside wall of the hoof. In many cases the laminæ of the bar, of the wall, or of both, are involved at the same time.

Three kinds of corns are commonly recognized--the dry, the moist, and the suppurative--a division based solely on the character of the conditions which follow the primary injury.

The fore feet are almost exclusively the subjects of the disease, for two reasons: First, because they support a greater part of the body; secondly, because the heel of the fore foot during progression is first placed upon the ground, whereby it receives much more concussion than the heel of the hind foot, in which the toe first strikes the ground.

_Causes._--It may be said that all feet are exposed to corns, and that even the best feet may suffer from them when conditions necessary to the production of the peculiar injury are present. The heavier breeds of horses generally used for heavy work on rough roads and streets seem to be most liable to this trouble. Mules rarely have corns.

Among the causes and conditions which predispose to corns may be named high heels, which change the natural relative position of the bones of the foot and thereby increase the concussion to which these parts are subject; contracted heels, which in part destroy the elasticity of the foot, increase the pressure upon the soft tissues of the heel, and render lacerations more easy; long feet, which by removing the frog and heels too far from the ground deprive them of necessary moisture; this, in turn, reduces the elastic properties of the horn and diminishes the transverse diameter of the heels; weak feet, or those in which the horn of the wall is too thin to resist the tendency to spread, whereby the soft tissues are easily lacerated. Wide feet with low heels are always accompanied with a flat sole whose posterior wings either rest upon the ground or the shoe, and as a consequence are easily bruised; at the same time the arch of the sole is so broad and flat that it can not support the weight of the body, and in the displacement which happens when the foot is rested upon the ground the soft tissues are liable to become bruised or torn.

It is universally conceded that shoeing, either as a direct or predisposing cause, is most prolific in producing corns. One of the most serious as well as the most common of the errors in shoeing is to be found in the preparation of the foot. Instead of seeking to maintain the integrity of the arch, the first thing done is to weaken it by freely paring away the sole; nor does the mutilation end here, for the frog, which is nature's main support to the branches of the sole and the heels, is also largely cut away. This not only permits of an excessive downward movement of the contents of the horny box, but it at the same time removes the one great means by which concussion of the foot is destroyed. As adjuncts to the foregoing errors must be added the faults of construction in the shoe and in the way it is adjusted to the foot. An excess of concavity in the shoe, extending it too far back on the heels, high calks, thin heels which permit the shoe to spring, short heels with a calk set under the foot, and a shoe too light for the animal wearing it or for the work required of him, are all to be avoided as causes of corns. A shoe so set so as to press upon the sole or one that has been on so long that the hoof has overgrown it until the heels rest upon the sole and bars becomes a direct cause of corns. Indirectly the shoe becomes the cause of corns when small stones, hard, dry earth, or other objects collect between the sole and shoe. Lastly, a rapid gait and excessive knee action, especially on hard roads, predispose to this disease of the feet.

_Symptoms._--Ordinarily a corn induces sufficient pain to cause lameness. It may be intense, as seen in suppurative corn, or it may be but a slight soreness, such as that which accompanies dry corn. It is by no means unusual in chronic corns to see old horses apparently so accustomed to the slight pain which they suffer as not to limp at all. But they are generally very restless. They paw their bedding behind them at night and often refuse to lie down for a long rest. The lameness of this disease, however, can hardly be said to be characteristic, for the reason that it varies so greatly in intensity; but the position of the leg while the patient is at rest is generally the same in all cases. The foot is so advanced that it is relieved of all weight, and the fetlock is flexed until all pressure by the contents of the hoof is removed from the heels. In suppurative corn the lameness subsides or entirely disappears as soon as the abscess opens. When the injured tissues are much inflamed, as may happen in severe and recent cases, the heel of the affected side, or even the whole foot, is hot and tender to pressure. In dry corn and in most chronic cases all evidences of local fever are often wanting. It is in these cases that the patient goes well when newly shod, for the smith cuts away the sole over the seat of injury until all pressure by the shoe is removed and lowers the heels so that concussion is reduced to a minimum.

If a corn is suspected, the foot should be examined for increased sensibility of the inside heel. Tapping the heel of the shoe with a hammer and grasping the wall and bar between the jaws of pincers with moderate pressure will cause more or less flinching if the disease is present. For further evidence the shoe is removed and the heel cut away with the drawing knife. As the horn is pared out, not only the sole in the angle is found discolored, but in many instances the insensible laminæ of the bar and wall adjacent are also stained with the escaped blood. In moist and suppurative corns this discoloration is less marked than in dry corn and even may be entirely wanting. In these cases the horn is soft, often white, and stringy or mealy, as seen in pumiced sole resulting from founder. When the whole thickness of the sole is discolored and the horn dry and brittle it is generally evidence that the corn is an old one and that the exciting cause has existed continuously. A moist corn differs from the dry one in that the injury is more severe. The parts affected are more or less inflamed, and the horn of the sole in the angle is undermined by a citron-colored fluid, which often permeates the injured sole and laminæ, causing the horn to become somewhat spongy.

A suppurative corn differs from others in that the inflammation ends in suppuration. The pus collects at the point of injury and finally escapes by working its way between the sensitive and insensible laminæ to the top of the hoof, where an opening is made between the wall and coronary band at or near the heels. This is the most serious form of corns, for the reason that it may induce gangrene of the plantar cushion, cartilaginous quittor, or caries of the coffin bone.

_Treatment._--Since a diversity of opinion exists as to what measures must be adopted for the radical cure of corns, the author will advise the use of those which have proved most efficient in his hands.

As in all other troubles, the cause must be discovered, if possible, and removed. In the great majority of cases the shoeing is at fault. While sudden changes in the method of shoeing are not advisable, it may be said that all errors, either in the preparation of the foot, in the construction of the shoe, or in its application may very properly be corrected at any time. Circumstances may at times make it imperative that shoes be worn which are not free from objections; as, for instance, the shoe with a high calk; but in such cases it is considered that the injuries liable to result from the use of calks are less serious than those which are sure to happen for the want of them.

For a sound foot perfectly formed, a flat shoe, with heels less thick than the toe, and which rests evenly on the wall proper, is the best. In flat feet it is often necessary to concave the shoe as much as possible on the upper surface, so that the sole may not be pressed upon. If the heels are very low the heels of the shoe may be made thicker. If the foot is very broad and the wall light toward the heels, a bar shoe resting upon the frog will aid to prevent excessive tension upon the soft tissues when the foot receives the weight of the body. A piece of leather placed between the foot and shoe serves largely to destroy concussion, and its use is absolutely necessary on some animals to enable them to work.

Last among the preventive measures may be mentioned those which serve to maintain the suppleness of the hoof. The dead horn upon the surface of the sole not only retains moisture for a long time, but protects the living horn beneath from the effects of evaporation; for this reason the sole should be pared as little as possible. Stuffing the feet with flaxseed meal, wet clay, or other like substances, or damp dirt floors or damp bedding of tanbark, greasy hoof ointments, etc., are all means which may be used to keep the feet from becoming too dry and hard.

As to the curative measures which are to be adopted much will depend upon the extent of the injury. If the case is one of chronic dry corn, with but slight lameness, the foot should be poulticed for a day or two and the discolored horn pared out, care being taken not to injure the soft tissues. The heel on the affected side is to be lowered until all pressure is removed and, if the patient's labor is required, the foot must be shod with a bar shoe or with one having stiff heels. Care must be taken to reset the shoe before the foot has grown too long, else the shoe will no longer rest on the wall, but on the sole and bar.

I believe in cutting moist corns out. If there is inflammation, cold baths and poultices should be used; when the horn is well softened and the fever allayed, pare out the diseased horn, lightly cauterize the soft tissues beneath, and poultice the foot for two or three days. When the granulations look red, dress the wound with oakum balls saturated in a weak solution of tincture of aloes or spirits of camphor and apply a roller bandage. Change the dressing every two or three days until a firm, healthy layer of new horn covers the wound, when the shoe may be put on, as in dry corn, and the patient returned to work.

In suppurative corns the loosened horn must be removed, so that the pus may freely escape. If the pus has worked a passage to the coronary band and escapes from an opening between the band and hoof, an opening must be made on the sole, and cold baths made astringent with a little sulphate of iron or copper are to be used for a day or two. When the discharge becomes healthy, the fistulous tracts may be injected daily with a weak solution of bichlorid of mercury, nitrate of silver, etc., and the foot dressed as after operation for moist corns. When complications arise, the treatment must be varied to meet the indications; if gangrene of the lateral cartilage takes place it must be treated as directed under the head of cartilaginous quittor; if the velvety tissue is gangrenous, it must be cut away; if the coffin bone is necrosed, it must be scraped, and the resulting wounds treated on general principles. After any of the operations for corns have been performed, in which the soft tissues have been laid bare, it is best to protect the foot by a sole of soft leather set beneath the shoe when the animal is returned to work. Only in rare instances are the complications of corns so serious as to destroy the life or usefulness of the patient. It is the wide, flat foot with low heels and thin wall which is most liable to resist all efforts toward effecting a complete cure.

BRUISE OF THE FROG.

When the frog is severely bruised the injury is followed by suppuration beneath the horn, and at times by partial gangrene of the plantar cushion.

_Causes._--A bruise of the frog generally happens from stepping on a rough stone or other hard object. It is more liable to take place when trotting, running, or jumping than when at a slower pace. A stone wedged in the shoe and pressing on the frog or between the sides of the frog and the shoe, if it remains for a time, produces the same results. A cut through the horny frog with some sharp instrument or a punctured wound by a blunt-pointed instrument may also cause suppuration and gangrene of the plantar cushion. Broad, flat feet with low heels and a fleshy frog are most liable to these injuries.

_Symptoms._--Lameness, severe in proportion to the extent of the bruise and the consequent suppuration, is always an early symptom. When the animal moves, the toe only is placed to the ground or the foot is carried and the patient hobbles along on three legs. When he is at rest, the foot is set forward with the toe on the ground and the leg flexed at the fetlock joint. As soon as the pus finds its way to the surface the lameness improves. If the frog is examined early the injured spot may usually be found; later, if no opening exists, the pus may be discovered working its way toward the heels. The horn is loosened from the deeper tissues, and, if pared through, a thin, yellow, watery and offensive pus escapes. In other cases a ragged opening is found in the frog, leading down to a mass of dead, sloughing tissues, which are pale green in color if gangrene of the plantar cushion has set in. In rare cases the coffin bone may be involved in the injury and a small portion of it may become carious.

_Treatment._--If the injury is seen at once, the foot should be placed in a bath of cold water to prevent suppuration. If suppuration has already set in, the horn of the frog, and of the bars and branches of the sole, if necessary, is to be pared thin so that all possible pressure may be removed, and the foot poulticed. When the pus has loosened the horn, all the detached portions are to be cut away. If the pus is discharging from an opening near the hair, the whole frog, or one-half of it, will generally be found separated from the plantar cushion, and is to be removed with the knife. After a few days the gangrenous portion of the cushion will slough off from the effects of the poultice; under rare circumstances only should the dead parts be removed by surgical interference. When the slough is all detached, the remaining wound is to be treated with simple stimulating dressings, such as tincture of aloes or turpentine, oakum balls, and bandages as directed in punctured wounds. When the lameness has subsided, and a thin layer of new horn has covered the exposed parts, the foot may be shod. Cover the frog with a thick pad of oakum, held in place by pieces of tin fitted to slide under the shoe, and return to slow work. Where caries of the coffin bone, etc., follow the injury the treatment recommended for these complications in punctured wounds of the foot must be resorted to.

PUNCTURED WOUNDS OF THE FOOT.

Of all the injuries to which the foot of the horse is liable, none are more common than punctured wounds, and none are more serious than these may be when involving the more important organs within the hoof. A nail is the most common instrument by which the injury is inflicted, yet wounds may happen from glass, wire, knives, sharp pieces of rock, etc.

A wound of the foot is more serious when made by a blunt-pointed instrument than when the point is sharp, and the nearer the injury is to the center of the foot the more liable are disastrous results to follow. Wounds in the heel and in the posterior parts of the frog are attended with but little danger, unless they are so deep as to injure the lateral cartilages, when quittor may follow. Punctured wounds of the anterior parts of the sole are more dangerous, for the reason that the coffin bone may be injured, and the suppuration, even when the wound is not deep, tends to spread and always gives rise to intense suffering. The most serious of the punctured wounds are those which happen to the center of the foot, and which, in proportion to their depth, involve the plantar cushion, the plantar aponeurosis, the sesamoid sheath, the navicular bone, or the coffin joint.

Punctured wounds are more liable to be deep in flat or convex feet than in well-made feet, and as a rule, recovery is neither so rapid nor so certain. These wounds are less serious in animals used for heavy draft than in those required to do faster work; for the former may be useful, even if complete recovery is not effected. Lastly, punctured wounds of the fore feet are more serious than of the hind feet, for the reason that in the former the instrument is liable to enter the foot in a nearly perpendicular line, and, consequently, is more liable to injure the deeper structures of the foot; in the hind foot, the injury is generally near the heels and the wound oblique and less deep.

_Symptoms._--A nail or other sharp instrument may penetrate the frog and remain for several days without causing lameness; in fact, in many cases of punctured wound of the frog the first evidence of the injury is the finding of the nail or the appearance of an opening where the skin and frog unite, from which more or less pus escapes. Even when the sole is perforated, if the injury is not too deep, no lameness develops until suppuration is established. In all cases of foot lameness, especially if the cause is obscure, the foot should be examined for evidence of injury.

The lameness from punctured wounds, accompanied with suppuration, is generally severe, the patient often refusing to use the affected member at all. The pain being lancinating in character, he stands with the injured foot at rest or constantly moves it back and forth. In other cases the patient lies down most of the time with the feet outstretched; the breathing is rapid, the pulse fast, the temperature elevated, and the body covered with patches of sweat.

When the plantar aponeurosis is injured, the pus escapes with difficulty and the wound shows no signs of healing; the whole foot is hot and very painful. If the puncture involves the sesamoid sheath, the synovial fluid escapes. At first this fluid is pure, like joint water, but later becomes mixed with the products of suppuration and loses its clear, amber color. Suppuration generally extends up the course of the flexor tendon, an abscess forms in the hollow of the heel, and finally opens somewhere below the fetlock joint. The whole coronet is more or less swollen, the discharge is profuse and often mixed with blood, yet the suffering is greatly relieved from the moment the abscess opens.

If the puncture reaches the navicular bone the lameness is intense from the beginning; but the only certain way to determine the existence of this complication is by the use of the probe; and unless there is a free escape of synovia it must be used with the greatest of care, else the coffin joint may be opened. If the coffin joint has been penetrated, either by the offending instrument or by the process of suppuration, acute inflammation of the joint follows, accompanied with high fever, loss of appetite, etc. The ankle and coronet are now greatly swollen, and dropsy of the leg to the knee or hock, or even to the body, often follows. If the process of suppuration continues, small abscesses appear at intervals on different parts of the coronet, the patient rapidly loses flesh, and may die from intense suffering and blood poisoning. In other cases the suppuration soon disappears, and recovery is effected by the joint becoming stiff (anchylosis).

When the wound is forward, near the toe, and deep enough to injure the coffin bone, caries always results. The presence of the dead pieces of bone can be determined by the use of the probe; the bone feels rough and gritty. Furthermore, there is no disposition upon the part of the wound to heal.

Besides the complications above mentioned, others equally as serious may be met with. The tendons may soften and rupture, the hoof may slough off, quittors develop, or sidebones and ringbones grow. Finally, laminatis of the opposite foot may happen if the patient persists in standing, or lockjaw may cause early death.

_Treatment._--In all cases the horn around the seat of injury should be thinned down, a free opening made for the escape of the products of suppuration, and the foot placed in a poultice. If the injury is not serious, recovery takes place in a few days. When the wound is deeper it is better to put the foot into a cold bath or under a stream of cold water, as advised in the treatment for quittor.

If the bone is injured, cold baths, containing about 2 ounces each of sulphate of copper and sulphate of iron, may be used until the dead bone is well softened, when it should be removed by an operation. The animal must be cast for this operation. The sole is pared away until the diseased bone is exposed, when all the dead particles are to be removed with a drawing knife, and the wound dressed with 3 per cent compound cresol solution or a 5 per cent solution of carbolic acid, oakum balls, and a roller bandage.

Wounds of the bone which are made by a blunt-pointed instrument, like the square-pointed cut nail, in which a portion of the surface is driven into the deeper parts of the bone, always progress slowly, and should be operated upon as soon as the conditions are favorable. Even wounds of the navicular bone, accompanied with caries, may be operated on and the life of the patient saved; but the most skillful surgery is required and only the experienced operator should undertake their treatment.