Chapter XXIII: Part 23

_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 laminae 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 laminae, 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 laminae 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.

If there is an escape of pure synovial fluid from a wound of the sole, without injury to the bone, a small pencil of corrosive sublimate should be introduced to the bottom of the wound and the foot dressed as directed above.

The other complications are to be treated as directed under their proper headings.

After healing of the wounds has been effected, lameness, with more or less swelling of the coronary region, may remain. In such cases the coronet should be blistered or even fired with the actual cautery, and the patient turned to pasture. If the lameness still persists, and is not due to a stiff joint, unnerving may be resorted to in many cases with very good results. If the joint is anchylosed, no treatment can relieve it, and the patient must either be put to very slow work or kept for breeding purposes only.

"_Prick in shoeing_" is an injury which should be considered under the head of punctured wounds of the foot. The nails by which the shoe is fastened to the hoof may produce an injury followed by inflammation and suppuration in two days, by penetrating the soft tissues directly or by being driven so deep that the inner layers of the horn of the wall are pressed against the soft tissues with such force as to crush them. In either case, unless the injury is at the toe, the animal generally goes lame soon after shoeing, when the first evidence of the trouble may be the discharge of pus at the coronet. If lameness follows close upon the setting of the shoes, without other appreciable cause, each nail should be lightly struck with a hammer, when the one at fault will be detected by the flinching of the animal.

Treatment consists in drawing the nail, and if the soft tissues have been penetrated or suppuration has commenced, the horn must be pared away until the diseased parts are exposed. The foot is now to be poulticed for a day or two, or until the lameness and suppuration have ceased. If the discharge of pus from the coronet is the first evidence of the disease, the offending nail must be found and removed, the horn pared out, and a weak solution of carbolic acid or compound cresol injected at the coronet until the fistulous tract has healed.

CONTRACTED HEELS, OR HOOFBOUND.

Contracted heels, or hoofbound, is a common disease among horses kept on hard floor in dry stables, and in such as are subject to much saddle work. It consists in an atrophy, or shrinking, of the tissues of the foot, whereby the lateral diameter of the heels is diminished. It affects the fore feet principally; but it is seen occasionally in the hind feet, where it is of less importance, for the reason that the hind foot first strikes the ground with the toe, and consequently less expansion of the heels is necessary than in the fore feet, where the weight is first received on the heels. Any interference with the expansibility of this part of the foot interferes with locomotion and ultimately gives rise to lameness. Usually but one foot is affected at a time, but when both are diseased the change is greater in one than in the other. Occasionally but one heel, and that the inner one, is contracted; in these cases there is less liable to be lameness and permanent impairment of the animal's usefulness. According to the opinion of some of the French veterinarians, hoofbound should be divided into two classes--total contraction, in which the whole foot is shrunken in size, and contraction of the heels, when the trouble extends only from the quarters backward. (Pl. XXXV, figs. 4 and 7.)

_Causes._--Animals raised in wet or marshy districts, when taken to towns and kept on dry floors, are liable to have contracted heels, not alone because the horn becomes dry, but because fever of the feet and wasting away of the soft tissues result from the change. Another common cause of contracted heels is to be found in faulty shoeing, such as rasping the wall, cutting away the frog, heels, and bars; high calks and the use of nails too near the heels. Contracted heels may happen as one of the results of other diseases of the foot; for instance, it often accompanies thrush, sidebones, ringbones, canker, navicular disease, corns, sprains of the flexor tendons, of the sesamoid and suspensory ligaments, and from excessive knuckling of the fetlock joint.

_Symptoms._--In contraction of the heels the foot has lost its circular shape, and the walls from the quarters backward approach to a straight line. The ground surface of the foot is now smaller than the coronary circumference; the frog is pinched between the inclosing heels, is much shrunken, and at times is affected with thrush. The sole is more concave than natural, the heels are higher, and the bars are long and nearly perpendicular. The whole hoof is dry and so hard that it can scarcely be cut; the parts toward the heels are scaly and often ridged like the horns of a ram, while fissures, more or less deep, may be seen at the quarters and heels following the direction of the horn fibers. (Plate XXXVI, fig. 10.) When the disease is well advanced lameness is present, while in the earlier stages there is only an uneasiness evinced by frequent shifting of the affected foot. Stumbling is common, especially on hard or rough roads. In most cases the animal comes out of the stable stiff and inclined to walk on the toe, but after exercise he may go free again. He wears his shoes off at the toe in a short time, no matter whether he works or remains in the stable. If the shoe is removed and the foot pared in old cases, a dry, mealy horn will be found where the sole and wall unite, extending upward in a narrow line toward the quarters.

_Treatment._--First of all, the preventive measures must be considered. The feet are to be kept moist and the horn from drying out by the use of damp sawdust or other bedding; by occasional poultices of boiled turnips, linseed meal, etc., and greasy hoof ointments to the sole and walls of the feet. The wall of the foot should be spared from the abuse of the rasp; the frog, heels, and bars are not to be mutilated with the knife, nor should calks be used on the shoe except when absolutely necessary. The shoes should be reset at least once a month to prevent the feet from becoming too long, and daily exercise must be insisted on.

As to curative measures, a diversity of opinion exists. A number of kinds of special shoes have been invented, having for an object the spreading of the heels, and perhaps any of these, if properly used, would eventually effect the desired result. But a serious objection to most of these shoes is that they are expensive and often difficult to make and apply. The method of treatment which I have adopted is not only attended with good results, but is inexpensive, if the loss of the patient's services for a time is not considered a part of the question. It consists, first, in the use of poultices or baths of cold water until the horn is thoroughly softened. The foot is now prepared for the shoe in the usual way, except that the heels are lowered a little and the frog remains untouched. A shoe, called a "tip," is made by cutting off both branches at the center of the foot and drawing the ends down to an edge. The tapering of the branches should begin at the toe, and the shoe should be of the usual width, with both the upper and lower surfaces flat. This tip is to be fastened on with six or eight small nails, all set well forward, two being in the toe. With a common foot rasp begin at the heels, close to the coronet, and cut away the horn of the wall until only a thin layer covers the soft tissues beneath. Cut forward until the new surface meets the old 2-1/2 or 3 inches from the heel. The same sloping shape is to be observed in cutting downward toward the bottom of the foot, at which point the wall is to retain its normal thickness. The foot is now blistered all round the coronet with Spanish-fly ointment; when this is well set, the patient is to be turned to pasture in a damp field or meadow. The blister should be repeated in three or four weeks, and, as a rule, the patient can be returned to work in two or three months.

The object of the tip is to throw the weight on the frog and heels, which are readily spread after the horn has been cut away on the sides of the wall. The internal structures of the foot at the heels, being relieved of excessive pressure, regain their normal condition if the disease is not of too long standing. The blister tends to relieve any inflammation which may be present, and stimulates a rapid growth of healthy horn, which, in most cases, ultimately forms a wide and normal heel. In old, chronic cases, with a shrunken frog and increased concavity of the sole, accompanied with excessive wasting of all the internal tissues of the foot, satisfactory results can not be expected and are rarely obtained. Still, much relief, if not an entire cure, may be effected by these measures.

When thrush is present as a complication, its cure must be sought by measures directed under that heading. If sidebones, ringbones, navicular disease, contracted tendons, or other diseases have been the cause of contracted heels, treatment will be useless until the cause is removed.

SAND CRACKS.

A sand crank is a fissure in the horn of the wall of the foot. These fissures are quite narrow, and, as a general rule, they follow the direction of the horny fibers. They may occur on any part of the wall, but ordinarily are only seen directly in front, when they are called toe cracks; or on the lateral parts of the walls, when they are known as quarter cracks. (Plate XXXVI.)

Toe cracks are most common in the hind feet, while quarter cracks nearly always affect the fore feet. The inside quarter is more liable to the injury than the outside, for the reason that this quarter is not only the thinner, but during locomotion receives a greater part of the weight of the body. A sand crack may be superficial, involving only the outer parts of the wall, or it may be deep, involving the whole thickness of the wall and the soft tissues beneath.

The toe crack is most likely to be complete--that is, extending from the coronary band to the sole--while the quarter crack is nearly always incomplete, at least when of comparatively recent origin. Sand cracks are most serious when they involve the coronary band in the injury. They may be complicated at any time by hemorrhage, inflammation of the laminae, suppuration, gangrene of the lateral cartilage and of the extensor tendon, caries of the coffin bone, or the growth of a horny tumor known as a keraphyllocele.

_Causes._--Relative dryness of the horn is the principal predisposing cause of sand cracks. Excessive dryness is perhaps not a more prolific cause of cracks in the horn than alternate changes from damp to dry. It is even claimed that these injuries are more common in animals working on wet roads than those working on roads that are rough and dry; at least these injuries are not common in mountainous countries. Animals used to running at pasture when transferred to stables with hard, dry floors are more liable to quarter cracks than those accustomed to stables. Small feet, with thick, hard hoofs, and feet which are excessively large, are more susceptible to sand cracks than those of better proportion. A predisposition to quarter cracks exists in contracted feet, and in those where the toe turns out or the inside quarter turns under.

Heavy shoes, large nails, and nails set too far back toward the heels, together with such diseases as canker, quittor, grease, and suppurative corns, must be included as occasional predisposing causes of sand cracks.

QUARTER-CRACK AND REMEDIES.]

FOUNDERED FEET.]

Fast work on hard roads, jumping, and blows on the coronet, together with calk wounds of the feet, are accidental causes of quarter cracks in particular. Toe cracks are more likely to be caused by heavy pulling on slippery roads and pavements or on steep hills.

_Symptoms._--The fissure in the horn is ofttimes the only evidence of the disease; even this may be accidentally or purposely hidden from casual view by mud, ointments, tar, wax, putty, gutta-percha, or by the long hairs of the coronet.

Sand cracks sometimes commence on the internal face of the wall, involving its whole thickness excepting a thin layer on the outer surface. In these cases the existence of the injury may be suspected from a slight depression, which begins near the coronary band and follows the direction of the horny fibers; but the trouble can only be positively diagnosed by paring away the outside layers of horn until the fissure is exposed. In toe cracks the walls of the fissure are in close apposition when the foot receives the weight of the body, but when the foot is raised from the ground the fissure opens. In quarter crack the opposition is true; the fissure closes when the weight is removed from the foot. As a rule, sand cracks begin at the coronary band, and as they become older they not only extend downward, but they also grow deeper. In old cases, particularly in toe cracks, the horn on the borders of the fissure loses its vitality and scales off, sometimes through the greater part of its thickness, leaving behind a rough and irregular channel extending from the coronet to the end of the toe.

In many cases of quarter crack, and in some cases of toe crack as well, if the edges remain close together, with but little motion, the fissure is dry; but in other cases a thin, offensive discharge issues from the crack and the ulcerated soft tissues, or a funguslike growth protrudes from the narrow opening.

When the cracks are deep and the motion of their edges considerable, so that the soft tissues are bruised and pinched with every movement, a constant inflammation of the parts is maintained and the lameness is severe.

Ordinarily the lameness of sand crack is slight when the patient walks, but it is greatly aggravated when he is made to trot, and the harder the road the worse he limps. Furthermore, the lameness is greater going downhill than up, for the reason that these conditions are favorable to an increased motion in the edges of the fissure. Lastly, more or less hemorrhage accompanies the inception of a sand crack when the whole thickness of the wall is involved. Subsequent hemorrhages may also take place from fast work, jumping, or a misstep.

_Treatment._--So far as preventive measures are concerned, but little can be done. The suppleness of the horn is to be maintained by the use of ointments, damp floor, bedding, etc. The shoe is to be proportioned to the weight and work of the animal; the nails holding it in place are to be of proper size and not driven too near the heels; sufficient calks and toe pieces must be added to the shoes of horses working on slippery roads; also, the evils of jumping, fast driving, etc., are to be avoided.

When a fissure has made its appearance, means are to be adopted which will prevent it from growing longer or deeper; this can only be done by arresting all motion in the edges. The best and simplest artificial appliance for holding the borders of a toe crack together is the Vachette clasp. These clasps and the instruments necessary for their application can be had of any prominent maker of veterinary instruments. (Pl. XXXVI.) These instruments comprise a cautery iron, with which two notches are burned in the wall, one on each side of the crack, and forceps with which the clasps are closed into place in the bottom of the notches and the edges of the fissure brought close together. The clasps, being made of stiff steel wire, are strong enough to prevent all motion in the borders of the crack. Before these clasps are applied the fissure should be thoroughly cleansed and dried, and if the injury is of recent origin the crack may be filled with a putty made of 2 parts of gutta-percha and 1 part of gum ammoniac. The number of clasps to be used is to be determined by the length of the crack, the amount of motion to be arrested, etc. Generally the clasps are from one-half to three-quarters of an inch apart. The clasps answer equally as well in quarter crack if the wall is sufficiently thick and not too dry and brittle to withstand the strain.

In the absence of these instruments and clasps a hole may be drilled through the horn across the fissure and the crack closed with a thin nail made of tough iron, neatly clinched at both ends. A plate of steel or brass is sometimes fitted to the parts and fastened on with short screws; while this appliance may prevent much gaping of the fissure, it does not entirely arrest motion of the edges, for the reason that the plate and screw can not be rendered immobile.

If, for any reason, the measures above fail or can not be used, recourse must be had to an operation. The horn is softened by the use of warm baths and poultices, the patient cast, and the walls of the fissure entirely removed with the knife. The horn removed is in the shape of the letter V, with the base at the coronet. Care must be taken not to injure the coronary band and the laminae. The wound is to be treated with mild stimulant dressings, such as compound cresol solution, a weak solution of carbolic acid, tincture of aloes, etc., oakum balls, and a roller bandage. After a few days the wound will be covered with a new, white horn, and only the oakum and bandages will be needed. As the new quarter grows out, the lameness disappears, and the patient may be shod with a bar shoe and returned to work.

In all cases of sand crack the growth of horn should be stimulated by cauterizing the coronary band or by the use of blisters. In simple quarter crack recovery will often take place if the coronet is blistered, the foot shod with a "tip," and the patient turned to pasture.

The shoe in toe crack should have a clip on each side of the fissure and should be thicker at the toe than at the heels. The foot should be lowered at the heels by paring, and spared at the toe, except directly under the fissure, where it is to be pared away until it sets free from the shoe.

When any of the complications referred to above arise, special measures must be resorted to. For the proper treatment of gangrene of the lateral cartilage and extensor tendon and caries of the coffin bone reference may be had to the articles on quittors. If the horny tumor, known as keraphyllocele, should develop, it is to be removed by the use of the knife. Since this tumor develops on the inside of the horny box and may involve other important organs of the foot in disease, its removal should only be undertaken by a skillful surgeon.

NAVICULAR DISEASE.

Navicular disease is an inflammation of the sesamoid sheath, induced by repeated bruising or laceration, and complicated in many cases by inflammation and caries of the navicular bone. In some instances the disease undoubtedly begins in the bone, and the sesamoid sheath becomes involved subsequently by an extension of the inflammatory process. (Plate XXXIV, fig. 5.)

The Thoroughbred horse is more commonly affected than any other, yet no class or breed of horses is entirely exempt. The mule, however, seems rarely, if ever, to suffer from it. For reasons which will appear when considering the causes of the disease, the hind feet are not liable to be affected. Usually but one fore foot suffers from the disease, but if both should be attacked the trouble has become chronic in the first before the second shows signs of the disease.

_Causes._--To comprehend fully how navicular disease may be caused by conditions and usages common to nearly all animals, it is necessary to recall the peculiar anatomy of the parts involved in the process and the functions which they perform in locomotion.

It must be remembered that the fore legs largely support the weight of the body when the animal is at rest, and that the faster he moves the greater is the shock which the fore feet must receive as the body is thrown forward by the propelling force of the hind legs. This shock could not be withstood by the tissues of the fore feet and legs were it not that it is largely dissipated by the elastic muscles which bind the shoulder to the body, the ease with which the arm closes on the shoulder blade, and the spring of the fetlock joint. Even these means, however, are not sufficient within themselves to protect the foot from injury; so nature has further supplemented them by placing the coffin joint on the hind part of the coffin bone instead of directly on top of it, whereby a large part of the shock of locomotion is dispersed before it can reach the vertical column represented by the cannon, knee, and arm bones. A still further provision is made by placing a soft, elastic pad--the frog and plantar cushion--at the heels to receive the sesamoid expansion of the flexor tendon as it is forced downward by the pressure of the coronet bone against the navicular. Extraordinary as these means may appear for the destruction of shock, and ample as they are when the animal is at a slow pace or unweighted by rider or load, they fail to relieve the parts completely from concussion and excessive pressure whenever the opposite conditions are present. The result, then, is that the coronet bone forces the navicular hard against the flexor tendon, which, in turn, presses firmly against the navicular as the force of the contracting muscles lifts the tendon into place. It is self-evident, then, that the more rapid the pace and the greater the load, the greater must these contending forces be, and the greater the liability to injury. For the same reason horses with excessive knee action are more liable to suffer from this disease than others, concussion of the foot and intense pressure on the tendon being common among such horses.

Besides the above-mentioned exciting causes must be considered those which predispose to the disease. Most prominent among these is heredity. It may be claimed, however, that an inherited predisposition to navicular disease consists not so much in a special susceptibility of the tissues which are involved in the process as in a vice of conformation which, as is well known, is liable to be transmitted from parent to offspring. The faults of conformation most likely to be followed by the development of navicular disease are an insufficient plantar cushion, a small frog, high heels, excessive knee action, and contracted heels. Finally, the environments of domestication and use, such as dry stables, heavy pulling, bad shoeing, punctured wounds, etc., all have their influence in developing this disease.

_Symptoms._--In the early stages of navicular disease the symptoms are generally very obscure. When the disease begins in inflammation of the navicular bone, the animal while at rest points the affected foot a time before any lameness is seen. While at work he apparently travels as well as ever, but when placed in the stable one foot is set out in front of the other, resting on the toe, with fetlock and knee flexed. After a time, if the case is closely watched, the animal takes a few lame steps while at work, but the lameness disappears as suddenly as it came, and the driver doubts whether the animal was really lame at all. Later the patient has a lame spell which may last during a greater part of the day, but the next morning it is gone; he leaves the stable all right, but goes lame again during the day. In times he has a severe attack of lameness, which may last for a week or more, when a remission takes place and it may be weeks or months before another attack supervenes. Finally, he becomes constantly lame, and the more he is used the greater the lameness.

In the lameness from navicular disease the affected leg always takes a short step, and the toe of the foot first strikes the ground; so the shoe is most worn at this point. If the patient is made to move backward, the foot is set down with exceeding great care, and the weight rests upon the affected leg but a moment. When exercised he often stumbles, and if the road is rough he may fall on his knees. If he is lame in both feet the gait is stilty, the shoulders seem stiff, and, if made to work, he sweats profusely from intense pain. Early in the development of the disease a careful examination will reveal some increased heat in the heels and frog, particularly after work; as the disease progresses this becomes more marked, until the whole foot is hot to the touch. At the same time there is an increased sensibility of the foot, for the patient flinches from the percussion of a hammer lightly applied to the frog and heels or from the pressure of the smith's pincers. The frog is generally shrunken, often of a pale-red color, and at times is affected with thrush. If the heels are pared away so that all the weight is received on the frog, or if the same result is attained by the application of a bar shoe, the animal is excessively lame. The muscles of the leg and shoulder shrink away and often tremble as the animal stands at rest. After months of lameness the foot is found to be shrunken in its diameter and apparently lengthened; the horn is dry and brittle and has lost its natural gloss, while circular ridges, developed most toward the heels, cover the upper part of the hoof. When both feet are affected the animal points first one foot then the other, and stands with the hind feet well forward beneath the body, so as to relieve the fore feet as much as possible from bearing weight. In old cases the wasting of the muscles and the knuckling at the fetlock become so great that the leg can not be straightened and locomotion can scarcely be performed. The disease generally makes a steady progress without inclining to recovery--the remission of symptoms in the earlier stages should not be interpreted as evidence that the process has terminated. The complications usually seen are ringbones, sidebones, thrush, contracted heels, quartercracks, and fractures of the navicular, coronet, and pastern bones.

_Treatment._--But few cases of navicular disease recover. In the early stages the wall of the heels should be rasped away, as directed in the treatment for contracted heels, until the horn is quite thin; the coronet should be well blistered with Spanish-fly ointment, and the patient turned to grass in a damp field or meadow. After three or four weeks the blister should be repeated. This treatment is to be continued for two or three months. Plane shoes are to be put on when the patient is returned to work. In chronic cases the animal should be put to slow, easy work. To relieve the pain, neurotomy may be performed--an operation in which the sense of feeling is destroyed in the foot by cutting out pieces of the nerve at the fetlock. This operation in nowise cures the disease, and, since it may be attended with serious results, can be advised only in certain favorable cases, to be determined by the veterinarian.

SIDEBONES.

A sidebone consists in a transformation of the lateral cartilages found on the wings of the coffin bone into bony matter by the deposition of lime salts. The disease is a common one, especially in heavy horses used for draft, in cavalry horses, cow ponies, and other saddle horses, and in runners and trotters.

Sidebones are peculiar to the fore feet, yet they occasionally develop in the hind feet, where they are of little importance since they cause no lameness. In many instances sidebones are of slow growth and, being unaccompanied with acute inflammation, they cause no lameness until such time as, by reason of their size, they interfere with the action of the joint. (Plate XXXIV, fig. 4.)

_Causes._--Sidebones often grow in heavy horses without any apparent injury, and their development has been attributed to the over-expansion of the cartilages caused by the great weight of the animal. Blows and other injuries to the cartilages may set up an inflammatory process which ends in the formation of these bony growths. High-heeled shoes, high calks, and long feet are always classed among the conditions which may excite the growth of sidebones. They are often seen in connection with contracted heels, ringbones, navicular disease, punctured wounds of the foot, quarter cracks, and occasionally as a sequel to founder.

_Symptoms._--In the earlier stages of the disease, if inflammation is present, the only evidence of the trouble to be detected is a little fever over the seat of the affected cartilage and a slight lameness. In the lameness of sidebones the toe of the foot first strikes the ground and the step is shorter than natural. The subject comes out of the stable stiff and sore, but the gait is more free after exercise.

Since the deposit of bony matter often begins in that part of the cartilage where it is attached to the coffin bone, the diseased process may exist for some time before the bony growth can be seen or felt. Later, however, the cartilage can be felt to have lost its elastic character, and by standing in front of the animal a prominence of the coronary region at the quarters can be seen. Occasionally these bones become so large as to bulge the hoof outward, and by pressing on the joint they so interfere with locomotion that the animal becomes entirely useless.

_Treatment._--So soon as the disease can be diagnosed active treatment should be adopted. Cold-water bandages are to be used for a few days to relieve the fever and soreness.

The improvement consequent on the use of these simple measures often leads to the belief that the disease has recovered; but with a return to work the lameness, fever, etc., reappears. For this reason the use of blisters, or, better still, the firing iron, should follow on the discontinuance of the cold bandages.

But in many instances no treatment will arrest the growth of these bony tumors, and as a palliative measure neurotomy must be resorted to. Generally this operation will so relieve the pain of locomotion that the patient may be used for slow work; but in animals used for fast driving or for saddle purposes, the operation is practically useless. Some years ago at Fort Leavenworth I unnerved a number of cavalry horses that were suffering from sidebones, and the records show that in less than seven months all were more lame than ever. Since a predisposition to develop sidebones may be inherited, animals suffering from this disease should not be used for breeding purposes unless the trouble is known to have originated from an accident.

RINGBONE.

A ringbone is the growth of a bony tumor on the ankle. This tumor is, in fact, not the disease, but simply the result of an inflammatory action set up in the periosteum and bone tissue proper of the pastern bones. (Plate XXXIV, fig. 1.) (See also p. 313.)

_Causes._--Injuries, such as blows, sprains, overwork in young, undeveloped animals, fast work on hard roads, jumping, etc., are among the principal exciting causes of ringbone. Horses most disposed to this disease are those with short, upright pasterns, for the reason that the shock of locomotion is but imperfectly dissipated in the fore legs of these animals. Improper shoeing, such as the use of high calks, a too great shortening of the toe and correspondingly high heels, predispose to this disease by increasing the concussion to the feet.

_Symptoms._--The first symptom of an actively developed ringbone is the appearance of a lameness more or less acute. If the bony tumor forms on the side or upper parts of the large pastern, its growth is generally unattended with acute inflammatory action, and consequently produces no lameness or evident fever. These are called "false" ringbones. But when the tumors form on the whole circumference of the ankle, or simply in front under the extensor tendon, or behind under the flexor tendons, or if they involve the joints between the two pastern bones, or between the small pastern and the coffin bone, the lameness is always severe. These constitute the true ringbone. Besides lameness, the ankle of the affected limb presents more or less heat, and in many instances a rather firm, though limited, swelling of the deeper tissues over the seat of the inflammatory process. The lameness of ringbone is characteristic in that the heel is first placed on the ground when the disease is in a fore leg, and the ankle is kept as rigid as possible. In the hind leg, however, the toe strikes the ground first, when the ringbone is high on the ankle, just as in health, but the ankle is maintained in a rigid position. If the bony growth is under the front tendon of the hind leg, or if it involves the coffin joint, the heel is brought to the ground first. In the early stages of the disease it is not always easy to diagnose ringbone, but when the deposits have reached some size they can be felt and seen as well.