Chapter 16

FAULTY CONFORMATION

Under this heading we shall deal with such formations of the feet as depart sufficiently from the normal to render them serious. Faulty conformation may be either congenital or acquired, and acquired gradually as the result of slowly operating causes, or suddenly as the sequel to previous acute disease. Whether congenital or acquired, serious in its nature or comparatively of no account, the veterinary surgeon will often find that the matter of conformation is one which will have a direct bearing on many of his 'foot' cases, and, furthermore, that it is one upon which he will often be called to give advice.

A. WEAK HEELS.

_Definition_.--That condition of the wall in which, owing to the softness of the horn and the oblique direction of the horn fibres, the heels are unable properly to bear the body-weight, and, as a consequence, curve in beneath the sole. We give the condition first mention, not because of its greater importance, but for the reason that it is frequently the forerunner of the condition to be next described--namely, contracted feet.

_Symptoms_.--The extreme point of the heel is not affected unless the foot has been greatly neglected, and the condition allowed to develop. Where, however, the foot has been uncared for, curving in of the wall takes place to an alarming degree, and the heels curl underneath the foot to such an extent as to grow over the sole and the bars. By the pressure they exert on the sole corns result, and the animal is lamed.

_Causes_.--In the main this defect is hereditary. It is seen commonly in connection with flat-foot, and where the horn of the wall is thin and shelly.

_Treatment_.--In the case of weak or 'turned in' heels no suitable bearing is offered for the shoe in the posterior half of the foot. Any attempt to induce the heels to bear weight is immediately followed by their bending in. It follows from this that the best shoe to be used here is one in which the bearing is confined to the anterior half of the wall, the heels being relieved by being sufficiently pared. As might be expected, this bearing on the anterior half only of the foot is insufficient; pressure must be given the frog. This latter end is best gained by a bar shoe (Fig. 68). With it the anterior portions of the wall, the whole of the bars, and the whole of the frog may be in contact, and the heels only so pared as to take no bearing at all. A few such shoeings sees the defect remedied. In every instance paring of the sole should be discouraged, as it serves but to increase the deformity.

B. CONTRACTED FOOT.

_(a)_ GENERAL CONTRACTION--CONTRACTED HEELS.

_Definition_. By the term contracted foot, otherwise known as hoof-bound, is indicated a condition in which the foot, more especially the posterior half of it, is, or becomes, narrower from side to side than is normal.

It must be borne in mind, however, that certain breeds of horses have normally a foot which nearer approaches the oval than the circular in form, and that a narrow foot is not necessarily a contracted foot.

The contraction may be bilateral when affecting both heels of the same foot and extending to the quarters, or unilateral when the inside or outside heel only is affected.

In some cases contraction is confined to one foot, while in others it may be noticed equally bad in both. It is a matter of common knowledge that contraction is usually seen in the fore-feet, while the hind seldom or never suffer from it, a fact which, to our minds, seems difficult of adequate explanation. Zundel explains this by stating that contraction is principally _observed_ in the fore-feet, by reason of the fact that when lameness arises from it alteration in action will more readily be detected in front than behind. Percival, on the other hand, suggests that the greater expansive powers of the hind-foot, by reason of the impetus of its action, is able to overcome any influence operating towards contraction. It may be, however, that given a cause for contraction, such as the removal of the frog's counter-pressure with the ground by faulty shoeing or excessive paring, the fore-feet, by reason of their being called upon to bear the greater part of the body-weight, are the first to suffer.

Flat feet with weak heels are those most frequently affected, and, as we have already intimated, the condition may exist with or without other disease of the foot.

Depending upon its degree, contracted foot may vary from a simple abnormality, non-inflammatory and painless, to a condition in which it becomes a veritable disease, giving rise to a bad form of lameness, and bringing about a withered and sometimes discharging and cankerous affection of the frog.

_Symptoms_.--In its early stages contraction is difficult of detection, and where both feet are affected may for some time go unsuspected. With only one foot undergoing change, the early stages may the more readily be marked, for in this case comparison with the other and sound foot will at once reveal the alteration in shape. If lameness in the suspected foot is present, then any lingering doubt will be quickly dispelled.

When far advanced, contraction offers signs that cannot well be missed. The converging of the heels narrows the V-shaped indentation in the sole for the reception of the frog. As a consequence of this, the frog itself becomes atrophied by reason of the _continual_ pressure exerted upon it by the ingrowing horn of the wall and the bars. The median and lateral lacunæ of this organ, from being fairly broad and open channels, become pressed into mere crack-like openings (see the commencing of this condition in Fig. 80, and a badly wasted frog in Fig. 74A). As the case goes on, the lateral branches of the frog entirely disappear, and all that is left of the organ is a remnant of its body or cushion, now wedged in tightly between the bars. Following upon the disappearance of the frog, we find that the bars are in contact, or, in some cases, actually overlapping each other at their posterior extremities.

At this stage, perhaps, the whole condition has become aggravated by a foul discharge from the place originally occupied by the frog, and the foot, especially in the region of the heels, has become hot and tender--really a form of local and subacute laminitis.

The long-continued inflammation, although only of a low type, renders the horn of the hoof hard and dry, and only with difficulty will the ordinary foot instruments cut it. This in its turn leads to cracks and fissures in various places, but more especially in the bars and what is left of the frog. Often, too, cracks will appear in the horn of the quarters, and a troublesome and incurable form of sand-crack results.

An animal with contraction advanced as far as this, especially if confined to one foot, goes unmistakably lame. With both feet affected, he ordinarily starts out from the stable in a manner that is commonly called 'groggy.' In other words, the gait is uncertain, and feeling; and stumbling is frequent. Anyone who has had the misfortune to drive an animal with feet in this condition knows full well that every little irregularity in the road at once makes itself felt to the feet, and that the animal, as time goes on, learns to carefully avoid any suspicious-looking group of stones he may see. To drive an animal like this is to keep one's self continually on tenter-hooks, for, sooner or later, the inevitable happens, and the animal comes down.

Up to now we have described the changes of form in the hoof as seen when the contracted foot is viewed from the solar surface. With those changes as evident as we have depicted them, there will be no difficulty in detecting the alterations in the form of the wall.

In addition to a narrowing from side to side there will be noticed an abnormal straightness of the quarters, with a turning in, more or less sudden, of the heels. This effect is given in these cases by the smith maintaining the shoe of a length and width that should normally fit a foot of that particular animal's size and substance. This is probably done with the idea of deceiving anyone examining the solar surface. Viewed from this position, the width of the shoe at the heels gives the impression that it is attached to a foot of normal breadth. This deception is heightened if at the same time has been practised the process of 'opening up the heels.' That expression indicates that the bars have been removed, and the lateral lacunæ of the frog made to continue the concavity of the sole. The arch of the latter is thus made to appear of much greater extent than it really is, and the heels, by reason of their being abruptly cut off when removing the bars, also convey the false impression of being wide apart.

The practitioner unversed in the tricks of the forge will best guard against this by viewing the foot, while on the ground, from behind. From that position he will be able to detect the lowness of the quarters, and the projecting portion of the shoe, that the hoof, by reason of its sudden bending inwards, does not touch.

The 'feeling' manner of the gait before alluded to, together with the disinclination to put the foot firmly and squarely forward, will sometimes lead the examiner to over-look the contraction, and diagnose his case as one of shoulder lameness. In many cases, too, such consequent conditions as 'thrushy frogs' and 'suppurating corns' are often treated with utter disregard of the contraction that has really brought them about. But above all, the disease most likely to be confounded with simple contraction is navicular disease. More than probable it is that many cases of so-called 'navicular' have in reality been nothing more than contraction brought about by one or other of the causes we shall afterwards enumerate--cases where a due attention to the prime cause of the mischief would, in all likelihood, have remedied the lameness.

_Changes in the Internal Structures_.--It follows as a matter of course that the changes we have described in the form of the hoof itself carry with them alterations in the bones and sensitive structures beneath it. The tissues, as a whole, become atrophied. The os pedis becomes deformed, loses its circular shape, and gradually becomes more or less oval in contour. At the same time, its structure becomes more compact, the cribriform appearance of its anterior and lateral faces more or less destroyed, and the few remaining openings apparently increased in size. This atrophy of the os pedis is best noted at the wings.

In the plantar cushion the effects of the atrophy are noted in the smallness of the organ, in its becoming whiter in colour than normal, and more resistant to pressure.

The coronary cushion is also affected in the same way, where the changes are noted most in its posterior portions.

A further effect of the narrowing of the heels, and their consequent tendency to drop downwards, is the exertion of a continual pressure on the sensitive sole. In course of time, and especially in flat feet, this leads to the appearance of corns.

The navicular bone and bursa and the tendon of the perforans also suffer from the effects of compression. The movement of the tendon is restricted, and arterial supply to the adjacent structures rendered deficient. The tissues of the bone and bursa are insufficiently nourished, and the secretion of synovia lessened. In this way it is conceivable that navicular disease may follow the condition of simple contracted heels.

In common with the other structures, the lateral cartilages also suffer from the continual pressure. Their blood-supply is lessened, their functions interfered with, and side-bones result.

_Causes_.--Upon the causation of contraction a very great deal has been written, both by early veterinarians and by those of the present day. Many and widely differing opinions have been advanced, but a careful résumé of only a few will lead one to certain fixed conclusions.

We may consider the causes of contraction under two headings--predisposing and exciting.

_Predisposing Causes of Contraction_.--Among these we will first mention heredity, although it is possible it should not be deemed of so great account as it is by some. That the shape of certain feet, especially those with low heels and abnormally sloping walls, predisposes to contraction no one will deny. So long, however, as the animal goes unshod, so long does the foot maintain a normal condition of the heels. In other words, it is not until the tendency to contraction already there is aggravated by careless shoeing and the effects of work that it operates to any noticeable extent.

The degree of contraction will also be very largely governed by the amount of the development of the frog. With a frog of good size, low down, and taking part in the pressure of the foot on the ground, contraction will be prevented. On the other hand, an ill-developed frog, one wasted by long-continued and spreading thrush, or one robbed of its normal function by excessive paring in the forge, is a common starting-point of the condition we are considering. We have already referred to this in Chapter III., when considering the experiments of Lungwitz in this connection. What we have to bear in mind in these experiments is that the application of a pad to the frog, in such a manner that effective ground-pressure is obtained, results always in a marked expansion of the heels, and that, with counter-pressure with the ground absent, expansion occurs to little or no extent. This is proof positive of the enormous part the frog plays in maintaining an open and elastic condition of the heels--a fact so insisted on by Coleman.

It is worthy of mention, however, that loss of the frog's function does not operate to nearly so serious an extent in horses with high, upright heels as in those with the heels low and excessively sloping.

In illustrating this, Mr. Dollar, in his work on shoeing, mentions the case of a pair of trotting horses of similar age, size, and weight, each having weak fore-heels. In one case the hoofs were flat, in the other upright. The horse with the flat hoofs suffered from contraction, while the other did not.

The reason appears to be that in the animal with upright hoofs the proportion of body-weight borne by the heels is considerably less than in those with the hoofs flat and sloping.

Certain conditions of the horn-producing membranes also predispose to contraction. For example, in horses reared on marshy soils, and afterwards transferred to standing in town stables, we find that a dry and brittle condition of the horn supervenes. This we may regard as a low form of laminitis, brought about by the heat of the material upon which the animal is standing, and the congestion of the feet engendered by his enforced standing for long periods in one position, as opposed to the more or less continuous exercise when at pasture. With the hoof in this condition it loses by evaporation the moisture that normally it should contain, and, as we might expect, a certain degree of contraction of its structure is the inevitable result.

We thus see that contraction brought about in this way is not so much caused by the heat of the stable, as it is by the decreased ability of the horn to retain its own moisture.

On the other hand, it cannot be denied that excessive warmth and dryness combined tend also to an undue abstraction of moisture, even from the horn of the healthy foot; and this explains in great measure how it is that lameness, as a rule, and especially that proceeding from contracted heels, is far more frequent and of greater intensity in the hot, dry months of summer, than in the cooler and more humid atmosphere of winter. It is interesting to note, too, that an alternation of humidity and dryness is far more liable to injure the quality of the horn and tend to its contraction than the long-continued effects of dryness alone. A common illustration of this is to be found in the effects of the ordinary poultice. Everyone knows that when, after a few days' application, they are discontinued, we get as a result an abnormally dry and brittle state of the horn. This is doubtless due to the poultice removing the thin, varnish-like, and protective pellicle known as the periople, and thereby allowing the process of evaporation to act on the water normally contained in the hoof.

_Exciting Causes of Contraction_.--Among these, first place must undoubtedly be given to shoeing. This does not necessarily imply shoeing more than ordinarily faulty, nor a faulty preparation of the foot, but shoeing as it is generally practised. No ordinary shoe, except a few devised for the purpose, such as the Charlier or the tip, allows the frog to come in contact with the ground. This we take to be the main factor in the causation of contracted heels, especially with a predisposition already present in the foot itself. In the words of Lungwitz: 'Regarded from this point of view, there is no greater evil than shoeing. It abolishes the necessary counter-pressure, and thus interferes with expansion. Bars, sole, and frog cannot perform the functions that naturally belong to them as they would do without the shoe.'

In addition to the evil of the shoe itself, errors of practice in the forge contribute to the causation of contraction. Taking first the preparation of the foot, we find that often the heels are lowered far too much, and the toe allowed to remain too long. This can have but one effect--that of throwing a greater proportion of the animal's weight upon the heels than properly they should bear, with, what we now know to be the consequence of that, a corresponding pushing inwards and downwards of the horn; in other words, contraction.

Excessive paring of the bars, to which we have already partly alluded, is also an active agent in bringing about an inward growth of the horn of the heels and quarters. The bar, or inflexion of the wall at the heel, by means of its close contact with the frog, communicates the outward movements of that organ to the wall of the hoof. With the bar removed, the outward movements of the frog under pressure are naturally rendered of no account, and a proper and intermittent expansion of the wall denied it. The same evil follows, though to a less extent, excessive paring of the sole.

The shape of the bearing surface of the shoe is often to be blamed. Where this is concave--'seated'--and the 'seating' is carried back to the heels, it is easy to see that, when weight is on the foot, there is an ever-present tendency for the bearing edge of the wall to slide down towards the inner edge of the shoe. This tendency, operating on both the inner and outer wall simultaneously, must strongly favour contraction.

A further wrong practice is that of continuing the nailing too far towards the heels. In our opinion this is not now often met with. When it occurs its effect is, of course, to prevent those movements of expansion of the wall which we now know to be normal and most marked at the heels.

It may be remarked of the build of the shoe, or of errors in the preparation of the foot, that neither are of much moment. Neither are they. But when one stays to consider that errors of this description are practised not only once, but each time the horse goes to the forge, and that with some of them--those relating to the build of the shoe--the injury thereby brought about is inflicted not only once, but every day that particular shoe is worn, then it is not to be wondered at that, sooner or later, ill consequences more or less grave result.

_Prognosis_.--This will depend to a very large extent upon the conformation of the limb, and upon the previous duration of the contraction. Contraction of long standing, where atrophy of the sub-lying, soft structures and the pedal bone may be expected, will prove obstinate to treatment. Especially will this be so if the lateral cartilages have become ossified. Neither may we look for much benefit from treatment if the contraction has occurred in animals with an oblique foot axis and flat hoofs.

On the other hand, if the case is comparatively recent, if the limb is straight and the form of the hoof is upright, and if matters are uncomplicated by side-bones, or other serious alteration in the internal structures, then treatment may be rewarded with some measure of success.

_Treatment_.--The greater part of the treatment of contracted foot will almost suggest itself as a corollary of the causes we have enumerated. The normal width of the heels may be renewed, and development of the wasted frog brought about by one of three methods:

1. By restoring the pressure from below to the frog.

2. By the use of an expansion shoe.

3. By operative measures upon the horn of the wall.

1. _By Restoring the Pressure from Below to the Frog_.

This may be accomplished as follows:

_(a) By Shoeing with Tips_.--This method is advocated by Percival, by A.A. Holcombe, D.V.S., Inspector. Bureau of Animal Industry, U.S.A., by Dollar in his work on horseshoeing, and by many others.

Though requiring more care than in fitting the ordinary shoe, the application of a tip is simple. In reality, the tip is just an ordinary shoe shortened by truncating the heels.

Before applying the tip, the horn of the wall at the toe should be shortened sufficiently to prevent any undue obliquity of the hoof, and the foot should be so prepared as to allow the heels of the tip to sink flush with the bearing edge of the wall behind it.

When the foot does not allow of the removal of much horn at the toe, what is termed a 'thinned' tip is to be preferred. Its shape is sufficiently shown by the accompanying figure (Fig. 65).

With the tip the posterior half of the foot is allowed to come into contact with the ground, and the object we are striving for--namely, frog pressure, and greater facilities for alternate expansion and contraction of the heels--is thus brought about.

_(b) By Shoeing with the Charlier_.--The results brought about by the use of a tip may be arrived at by the application of a Charlier or preplantar shoe, or by a modified Charlier or Charlier tip.

Briefly described, a Charlier is a shoe that allows the sole and the frog to come to the ground exactly as in the unshod foot. This is accomplished by running a groove round the inferior edge of the hoof by removing a portion of the bearing edge of the wall with a specially devised drawing-knife. Into this groove is fitted a narrow and somewhat deep shoe, made, preferably, of a mixture of iron and steel, and forged in such a manner that its front or outer surface follows the outer slope of the wall.

The Charlier should have the inner edge of its upper surface very slightly bevelled, in order to prevent any pressure on the sensitive sole, and should be provided with from four to six nail-holes. These latter should be small in size and conical in shape. The nails themselves should be small, and have a conical head and neck, to fit into the nail-hole of the shoe.

The modified Charlier, or Charlier tip, perhaps the better of the two for the purpose we are describing, is really a shortened Charlier, and bears the same relation to the Charlier proper as the tip does to the ordinary shoe. It is let into the solar surface of the foot in exactly the same manner as its larger fellow, but it does not extend backwards beyond the commencement of the quarters. By its use greater opportunity for expansion is given to the heels than is done by the Charlier with heels of full length.

We do not here intend to deal at any length with the arguments for and against the Charlier as regards its adoption for general use. These will be found fully set out in any good work on shoeing.

The point that it is correct in theory it would be idle to attempt to evade; but that it is generally practicable, or that it offers any very pronounced advantages, as compared with the disadvantages urged against it, over the shoes in ordinary use, the limited favour it has drawn to itself, since its introduction in 1865, seems sufficiently to deny.

_(c) By the Use of a Bar Shoe_.--Where the frog is not excessively wasted benefit will be derived from the use of a bar shoe.

The transverse portion at the back, termed the 'bar,' and which gives the shoe its name, is instrumental in bringing about from below that counter-pressure on the frog that we now know to be so necessary a factor in remedying contraction. When the frog, by wasting or disease, is so deficient as to be unable to reach the 'bar,' this shoe must be supplemented by a leather or rubber sole.

In the event of corn or sand-crack existing with the contraction, the shoe known as a 'three-quarter bar' is preferable (see Fig. 103). The break here made in the contour of the shoe allows of dressing the corn, and, in the case of sand-crack, removes the bearing from that portion of the wall. _(d) By the Use of a Bar Pad and a Heelless or 'Half' Shoe_.--The bar pad consists of a shape of rubber composition firmly fixed to a leather foundation, which shape of rubber takes the place of the 'bar' of the bar shoe.

For habitual use in such cases as prove obstinate to treatment, or where a complete cure was never from the commencement expected, the bar pad is undoubtedly one of the most useful inventions to our hand. The animal's 'going' is improved, the tender frog is protected from injury by loose stones, and greater comfort given to both the horse and the driver.

_(e) By the Use of a Frog Pad and a Shoe of Ordinary Shape_.--The shape of rubber on this pad is designed to cover the frog only. Its shape and mode of application is sufficiently shown in the accompanying illustrations.

_(f) By turning out to Grass_.--Where the expense of keep is no object, a return of contracted feet to the normal may be brought about by removing the shoes and turning the animal out to pasture, thus giving the feet the advantages to be derived from a more or less continuous operation of the normal movements of expansion and contraction. In this case the treatment must extend from three to four, or possibly six months.

2. _By the Use of Some Form of Expansion Shoe_.

[Footnote A: The inventor of this shoe uses the word 'grip' to denote what, in describing other expansion shoes, we term the 'clip' (H.C.R.).]

_(a) Smith's_.--For many years past continental writers have been practising this method. So far as we know, however, Lieutenant-Colonel Fred Smith was the first English veterinarian to use a shoe of his own devising, and to report on its effects. This shoe we will, therefore, give first mention.

The above figure, with its accompanying letterpress, sufficiently explains the nature of the shoe. In fitting the shoe, care must be taken to have the hinges (_f, f_) far enough back, or the shoe will have a tendency to spring at the heels, and the grips _(e, e)_, which catch on the bars, will have a difficulty in biting. This trouble will be avoided by having the hinges about 1-1/2 to 2 inches from the heels.

After the shoe has been firmly nailed to the foot, the travelling nut _b_ is driven forward on the screw _a_ so as to cause the grips to just catch on the inside of the bars of the foot. According to the inventor, the amount of pressure to be exerted must be learned by experience, and he says:

'I screw up very gradually until I see the cleft of the frog just beginning to open. I now trot the horse up, and if he goes sound it is certain that the pressure I have exercised will not give rise to trouble. The animal is sent to work to assist in the expansion of the foot. On examining the shoe next day, the grip is found to be quite loose, the foot has enlarged, and the nut is turned once more until the grip on the bars is tightened, the horse being again trotted to ascertain that no injurious pressure is exerted.

'Every day or two I repeat this process, making measurements in all cases before widening the heels. The increase in width of the foot which results is astonishing, 1/4 to 3/8 inch during the first week may be safely predicted, and in a month to six weeks it is impossible to recognise in the large healthy frog and wide heels, the shrivelled-up organ of a short time before.'[A]

[Footnote A: _Journal of Comparative Pathology and Therapeutics_, vol. v., p. 98.]

It is pointed out by the writer of the above (and his observations, doubtless, apply to the use of all other expansion shoes in which the bars are gripped and forcibly expanded) that the whole secret of success lies in avoiding injurious pressure by exerting too great an expansion at one operation. After each manipulation of the expanding apparatus the horse should trot sound and the frog remain cool. Should the foot become hot, and lameness supervene, then tension should at once be relaxed.

_Recorded Cases of the Use of the Shoe_.--The inventor of the shoe relates two cases of contracted foot treated by these means in which the heels of one, after thirty-nine days' treatment, had increased in width to the extent of 1 inch, and the heels of the other, after twenty-four days', had enlarged 5/8 inch. Of the first case he gives the drawings in Fig. 74.

A represents the foot before treatment; B the same foot after nine days' treatment, when the heels had widened 3/4 inch; and C the same foot at the end of the thirty-nine days' treatment, at which date the frog was an excellent-looking one, and the foot had increased an inch in width.[A]

[Footnote A: _Journal of Comparative Pathology and Therapeutics_, vol. v., p. 100]

In 1893, at a meeting of the Midland Counties Veterinary Medical Association, the late Mr. Olver said he had applied this shoe to a valuable hunter that had gone so lame that he could scarcely put his foot to the ground. After a fortnight's application, and by the assistance of the double screw in the shoe, the heel was forced out. Then the horse was put to work with the shoe on, and he had hunted the whole of the last season in a perfectly sound condition.[A]

[Footnote A: _Veterinary Record_, vol. vi., p. 143]

F.D. McLaren, M.R.C.V.S., writes:[A] 'I resolved to try one of Captain Smith's shoes in a case where the hoof was badly contracted, and where the frog had entirely disappeared, there being also slight lameness. The roof rapidly expanded, and every other day the nut was moved on a bit to keep the cross-piece tight. I then had the cross-piece bent downwards a little _to prevent the nut pressing on the rapidly-growing frog_.[B] After another fortnight or so, I had a shoe made with clips resting against the inside of the bars,[C] and the next time he was shod these were also dispensed with. It is now a year ago since the animal recovered his frog, and he still has the largest frog in the stable, and the hoof shows no sign of contraction.'

[Footnote A: _Ibid_., vol. vi., p. 183]

[Footnote B: The italics are mine (H.C.R.).]

[Footnote C: The expanding shoe itself was here evidently dispensed with, and an ordinary shoe with bar-clips used in its stead (H.C.R.).]

_(b) De Fay's_.--Among other shoes of the expansion class may be mentioned that of De Fay. Like the preceding, it is a shoe with a flat bearing surface, and provided with bar-clips. It is, however, _un_ hinged. The requisite degree of periodic expansion is in this case arrived at by a forcible widening of the heels of the shoe, accomplished by bending the substance of which it is made, and for this purpose the instrument illustrated in Fig. 75 is employed.

The foot is first properly trimmed by levelling the heels and thinning the sole on each side of the frog. The shoe is then fixed by nails in the ordinary manner, taking care that the last nails come not too far back, and that the clips rest evenly and firmly on the inside of the bars.

The dilator, hoof-spreader, or vice, as it is variously called, is then applied, its two jaws (_a_ and _b_) fitting against the inner edge of the shoe at the heels. Careful note is taken of the width of the hoof as measured on the graduated scale (_e_, _e_), and the double screw (_g_, _h_) revolved by means of the wrench (k), until the opening of the jaws thus obtained registers an expansion of 1/12 to 1/8 inch.

The dilatation is repeated at intervals of from eight to ten days, until, at the expiration of a month or six weeks, the amount of total expansion of the heels registers nearly an inch. That the method requires the greatest care may be gathered from the reports of continental writers. They state that frequently the pain and consequent lameness keep the patient confined to the stable for several days.

Numerous and but slightly differing forms of the dilator are on the market. As in principle they are all essentially the same, and are to be found illustrated in any reliable instrument catalogue, they need no description here.

_(c) Hartmann's_.--A further useful expansion shoe is that of Hartmann's (Fig. 76), in that it may be adapted for either unilateral or bilateral contraction. This shoe is also provided with bar-clips, and forcibly expanded at the heels by means of a dilator. The expansion is governed by saw-cuts through the inner margin of the shoe directed towards its outer margin, and running only partially through the inner half of the web (see Fig. 76).

According as the contraction is confined to the inner or outer heel, the saw-cuts, one or two in number, are placed to the inner or outer side of the toe-clip. When the contraction is bilateral, the saw-cuts, one or more in number, are placed on each side of the toe-clip.

_(d) Broué's_.--This is one of the forms of so-called 'slipper' shoes (see Fig. 77). We have already indicated that the shape of the bearing surface of the ordinary shoe--by its 'seating' or sloping from outside to inside--is sometimes a cause of contraction. In the 'slipper' of Broué this bearing is reversed, and the slope is from inside to outside. In the original form of this shoe the slope to the outside was continued completely round the shoe. Experience taught that the strain this enforced upon the junction of the wall with the sole was injurious, and that the 'reversed seating,' if we may so term it, was best confined to the hinder portions of the shoe's branches.

The amount of slope should not be excessive. If it is, too rapid and too forcible an expansion takes place, and pain and severe lameness results. Dollar gives the requisite degree of incline by saying that the outer margin of the bearing surface of the shoe should be from 1/12 to 1/8 inch lower than the inner.

In the case of the Broué slipper, it is the animal's own weight that brings about the widening of the heels, the slope or outward incline of the slipper simply causing the inferior edge of the wall at the heels to spread itself outwards instead of sliding inwards on the bearing surface of the shoe.

_(e) Einsiedel's_.--Like the 'slipper' of Broué, the Einsiedel shoe depends for its effects upon the slope of the bearing surface.

It differs from the Broué in being provided with a 'bar-clip.' This, in addition to gripping the bars like the bar-clips of other expanding shoes, also assists, under the body-weight, in expanding the heels by the pronounced slope given to its upper surface. The expanding force exerted by the body-weight falls thus, through the medium of the bar-clip, clip, _partly_ upon the bars, instead of, as in the Broué, solely upon the wall. We say _partly_ advisedly, for, in addition to the slope upon the outer side of the bar-clips, the bearing surface of the heels of the shoe is _slightly_ sloped outwards also. The good office served by the bar-clip is the lessening of any tendency to strain upon the white line.

Those we have described by no means exhaust the number of expansion shoes that have been devised. There are numerous others, many of which are composed of three-hinged portions, the two hindermost of which are gradually separated by a toothed arrangement of their inner margins and a travelling bar, the disadvantage of which is that it is liable to work loose. In the majority of this class of shoe the hinges are placed far forward, one on each side of the toe. They there become exposed to excessive wear. In fact, against the bulk of this form of shoe it may be urged that they cannot be worn by the animal at work, that they are expensive, difficult to make, and easily put out of order.

3. _By Operations on the Horn of the Wall_.

_(a) Thinning the Wall in the Region of the Quarters_.--This is best done by means of an ordinary farrier's rasp. The thinning should lessen gradually from the heel for 2-1/2 to 3 inches in a forward direction. That portion of the wall next to the coronary border, about 1/2 inch in breadth, should not be touched. At this point the thinning should commence, should be at its greatest, and lessen gradually downwards until at the inferior margin of the wall the normal thickness of horn is left. The animal is then shod with a bar shoe and the hoof bound with a bandage soaked in a mixture of tar and grease, in order to keep the thinned portion of the wall from cracking. In this condition the animal may remain at light labour.

When possible, however, it is better to combine the thinning process thus described with turning out to grass. In this case the ordinary shoe is first removed, and the foot poulticed for twenty-four hours to render the horn soft. The foot is then prepared by slightly lowering the heels--leaving the frog untouched--and thinning the quarters in exactly the manner described above.

After this is done, the animal is shod with an ordinary tip, a sharp cantharides blister applied to the coronet, and then turned out in a damp pasture. In this case the object of the tip is to throw the weight on to the heels and quarters. The thinned horn yields to the pressure thus applied, and a hoof with heels of a wider pattern commences to grow down from the coronet. Two to three months' rest is necessary before the animal can again he put to work.[A]

[Footnote A: This is the treatment strongly advocated by A.A. Holcombe, D.V.S., Inspector, Bureau of Animal Industry, U.S.A.]

_(b) Thinning the Wall in the Region of the Toe_.--This is done with the idea that the tendency of the heels to expand under pressure of the body-weight is helped by the thinned portion at the toe allowing the heels to more readily open behind. Seeing that in the case of toe sand-crack the converse is argued--that contraction of the heels readily takes place and forces the sand-crack wider open--it is doubtful whether this method is of any utility in treating contracted heels.

_(c) Grooving the Wall Vertically or Horizontally, and Shoeing with a Bar Shoe_.--Marking the wall with a series of grooves, each running in a more or less vertical direction, was suggested to English veterinarians by Smith's operation for side-bones.

The manner of making the grooves, and the instruments necessary, will be found fully described in Section C of Chapter X.

That the method is followed by satisfactory results the undermentioned case will show:

'A mare, which I have had in my possession since she was a foal, has always had contracted feet, which were also unnaturally small.... Lately the mare has been going very "short," and at length her action was quite crippled. At times she was decidedly lame on the off fore-foot. At no time have I been able to detect any sign of structural disease. I thereupon concluded that the lameness was due to mechanical pressure on the sensitive structures, and I determined to try the effects of the above treatment. As this was my first experience of the process, I was careful to carry it out in all its details, as described by Professor Smith. After the bar shoes had been put on, the mare was very lame. I allowed her two days' rest, then commenced regular walking exercise, and she daily improved. After fourteen days there was no lameness, but still short action. I thereupon gave the mare another week's walking exercise, at the expiration of which I drove her a short turn of five miles, which she did quite well, and free from lameness. For three months I kept the saw-cuts open to the coronet, and continued the bar shoes, keeping the mare at exercise, and giving her occasionally a drive. She never liked the bar shoes, and I was glad when I could discontinue them, which I did in the fourth month. When shod with the usual shoes the complete success of the treatment was shown. I have now had her going with the ordinary shoes for the past two or three months, and the improvement in the shape of the feet is very marked; there is no lameness; the mare is free in movement, fast, and spirited, whereas previously she was quite the reverse, and almost unfit to drive.'[A]

[Footnote A: W.S. Adams, M.R.C.V.S., _Veterinary Journal_, vol. xxx., p. 19.]

This method, though but recently introduced to the English veterinary surgeon, is by no means new. According to Zundel, it was recently made known on the Continent by Weber, but was previously known and mentioned by Lagueriniere, Brognier, and Hurtrel d'Arboval.

When the grooving is in a horizontal direction, a single incision is sufficient. This is made 3/4 inch below the coronary margin of the wall, and parallel with it, extending from the point of the heel for 2 or 3 inches in a forward direction. As in the previous method, a bar shoe is applied, and the animal daily exercised. Thus separated from the fixed and contracted portion of the wall below, the more elastic coronet under pressure of the body-weight commences to bulge. The bulging is of such an extent as to cause the new growing hoof from the top to considerably overhang the contracted portion below, and cure of the condition results from the newly-expanded wall above growing down in a normal direction.

This consideration of contracted heels may be concluded by drawing attention to the advisability of always maintaining the horn of the wall in as soft and supple a condition as is natural by the application of suitable hoof dressings.

A useful one for the purpose is that made with lard, to which has been added a small quantity of wax or turpentine.

Especially should a dressing like this be used when the hoof is inclined to be hard and brittle, and where tendency to contraction has already been noticed.

The application of a hoof ointment is also particularly indicated where the foot is much exposed to dampness, where the animal is compelled to stand for long periods upon a dry bedding, or where the bedding is of a substance calculated to have a deleterious effect upon the horn.

This, in conjunction with correct shoeing, will probably serve to avoid the necessity for more drastic measures at a later time.

_(b)_ LOCAL OR CORONARY CONTRACTION.

_Definition_.--Contraction at the heels, confined to the horn immediately succeeding that occupied by the coronary cushion. Really, the condition is but a somewhat arbitrary subdivision of contracted hoof, as we have just described it in general. For that reason we shall give it but very brief mention.

_Symptoms_.--In this case the horn of the heels, instead of running down in a straight line from the coronary margin to the bearing surface of the wall, presents a more or less distinct concavity (See Fig. 79, _a_, _a_).

As is the case with contraction considered as a whole, this deformity may affect one or both heels; and during its first appearance, which is after the first few shoeings, the animal may go distinctly lame.

_Causes_.--Coronary contraction may occur in hoofs of normal shape immediately shoeing is commenced, and frog pressure with the ground removed. It is far more likely to ensue, however, if the hoof is flat, with the heels low, and the wall sloping. And with those predisposing circumstances it is that the horse goes lame, and not with the hoof of normal shape.

Seeing, then, that this condition is largely dependent upon the shape of the foot, we may, to some extent, regard it as hereditary. Seeing further, however, that it only appears when shoeing is commenced, we may in a greater degree also regard it as acquired. The lesson, therefore, that this and other forms of contraction should teach us is the carefulness with which the shoeing should be superintended in a large stud, or in any case where the animal is of more than ordinary value.

The explanation of the restricted nature of this form of contraction is simple enough. We have only to refer to the lessons taught by the experiments of Lungwitz, described in Chapter III., and the condition almost explains itself. We remember that, briefly, the coronary margin of the wall resembles a closed elastic ring, which yields and expands to local pressure, no matter how slight. We remember also that removal of the counter-pressure of the frog with the ground tended to contraction of the wall's solar edge when weight was applied. Connect these two facts with the experience that this form of contraction more often than not occurs in hoofs with sloping heels, and we arrive at the following:

1. The excessive slope of the heels tends to throw a more than usual part of the body-weight upon the posterior portion of the coronary margin of the wall, with a consequent expansion of that part of the coronary margin implicated.

2. That the shoeing, in removing the counter-pressure of the frog with the ground, is at the same time tending to bring about contraction of the lower portions of the wall at the heels and quarters.

3. That this tendency to contraction will at first appear in the thinner portion of the area of wall named--namely, in that immediately below the bulging coronary margin.

We thus get the appearance depicted in Fig. 79--a contraction _(a, a)_ of the heels in the horn below the coronary margin, with the coronary margin itself bulging above, and a hoof of apparently normal width below.

We say 'apparently' with a purpose, for, as actual measurements will show, the wall near the solar edge is really contracting, for reasons which we have just described connected with shoeing. Its 'appearance' of normal width is accounted for thus: The contraction at _a, a_ is caused by the dragging inwards of the coronary cushion brought about by the sinking downwards of the plantar cushion, with which body it will be remembered the coronary cushion is continuous. With the constant dragging in and down of the coronary cushion there is given, to the horn-secreting papillæ, studding both the lower third of its outer face and its lowermost surface, a distinct 'cant' outwards. Below the lowermost limit of the coronary cushion, then, by reason of the cant outwards of the coronary papillæ in the situations mentioned, the horn of the wall takes a more outward direction than normal, a fact which lessens in effect the contraction as a whole really going on. It is interesting, too, to note that by this outward cant of the wall below, and the bulging of the coronary margin above it, the contraction (_a, a_) is heightened in effect, and caused to appear greater than really it is.

From what we have said it follows that contraction of the heels, excepting the extreme coronary margin, is existent generally, and not confined solely to _a, a_.

We have, then, in this condition, as we indicated at the commencement, but a phase in the evolution of ordinary contracted heels, for, with the progress of the contraction already existing at _a, a_, and below those points, it is only fair to assume that with it falling in of the at present bulging coronary margin must sooner or later occur, that, though expanded when compared with the wall below it, it will be really contracted as compared with what it was once in that same foot.

We may therefore conclude this section by remarking that factors tending to contraction of the heels in general are equally potent in the causation of contracted coronet alone.

_Treatment_.--Exactly that described for contracted heels. Bearing in mind that contracted coronary margin is but the onset of contracted heels, and that its first exciting cause is that of removal of the ground-pressure upon the frog, the most careful attention must be paid to the shoeing. The use of bar shoes, ordinary frog pads, or heelless shoes and bar pads, are especially indicated, together with abundant exercise. By these means the normal movements of expansion will be brought into play, and the condition quickly remedied.

C. FLAT-FOOT.

_Definition_.--By this term is indicated a condition of the foot where the natural concavity of the sole is absent.

_Symptoms_.--In the flat-foot the inferior edge of the wall, the sole, and the frog, all lie more or less in the same plane. It is a condition observed far more frequently in fore than in hind limbs, and is seen in connection with low heels, more or less obliquity of the wall, and a tendency to contraction. The action of the animal with flat feet is heavy, a result partly of the build of the foot, and partly of the tenderness that soon comes on through the liability of the sole to constant bruising.

_Causes_.--Flat-foot is undoubtedly a congenital defect, and is seen commonly in horses of a heavy, lymphatic type, and especially in those bred and reared on low, marshy lands. It is thus a common condition of the fore-feet of the Lincolnshire shire.

As might be expected, a foot of this description is far more prone to suffer from the effects of shoeing than is the foot of normal shape, and regarded in this light shoeing may be looked upon as, if not an actual cause, certainly a means of aggravating the condition. Directly the shoe--or at any rate the ordinary shoe--is applied, mischief commences. The frog is raised from the ground, and the whole of the weight thrown on to the wall. The heels, already weak and inclined to turn in, are unable to bear the strain. They _turn in_, and contraction commences. This 'turning in' of the heels is favoured by the undue obliquity of the wall. At the same time, the sole being archless, a certain amount of elasticity is lost. The weight is thrown more on to the heels, and the os pedis slightly descends, rendering the flatness of the sole even more marked than before. With the loss of elasticity of the sole concussion makes itself more felt. The animal is easily lamed, bruised sole becomes frequent, and corns sooner or later make their appearance.

_Treatment_.--Flat-foot is incurable. All that can be done is to pay careful attention to the shoeing, and so prevent the condition from being aggravated. In trimming the foot the sole should not be touched; the frog, too, should be left alone, and the wall pared only so far as regards broken and jagged pieces.

The most suitable shoe is one _moderately_ seated. If the seating is excessive, and bearing allowed only on the wall, there is a tendency for the wall to be pushed outwards, and for the sole to drop still further. On the other hand, if the seating is insufficient, or the web of the shoe too wide, and too great a bearing thus given to the sole, then we get, first, an undue pressure upon the last-named portion of the foot a bruise, and, finally, lameness. The correct bearing should take in the whole of the wall and the whole of the white line, and should _just impinge_ upon the sole. Above all, the heels of the shoe should be of full length, otherwise, if the shoe is worn just a little too long, its heels are carried under the sole of the foot, and by pressure there produce a corn.

If, with these precautions in shoeing flat-foot, tenderness still persists, a sole of leather or gutta-percha must be used with the shoe.

D. PUMICED-FOOT, DROPPED SOLE, OR CONVEX SOLE.

_Definition_.--This term is applied to the foot when the shape of the sole is comparable to the bottom of a saucer. When least marked it is really an aggravated form of flat-foot.

_Symptoms_.--In pumiced-foot the sole projects beyond the level of the wall. The obliquity of the latter is more marked than in the previous condition, and progression, to a large extent, takes place upon the heels. In addition to its deformity, the horn is greatly altered in quality, and, as the name 'pumice' indicates, is more or less porous in appearance, bulging, and brittle.

_Causes_.--As a general rule, it may be taken that pumiced-foot is a sequel of previous disease, although in its least pronounced form it may occur as the result of accidental or other causes, such as those described in the causation of flat-foot.

Occurring in its most marked form, there is no gainsaying the fact that pumiced-foot is a sequel of either acute or subacute laminitis. As we shall see when we come to study that disease, the dropping of the sole is brought about by distinct and easily-understood morbid processes affecting the sensitive structures. Briefly, these morbid processes in laminitis may be described thus: The accumulated inflammatory exudate, and in some cases pus, weakens and destroys the union between the sensitive and insensitive laminæ. This separation, for reasons afterwards to be explained, is greatest in the region of the toe. The os pedis, loosened from its intimate attachment with the horny box, is dropped upon the sole, and the sole, unable to bear the weight, commences to bulge below.

The altered character of the horn is accounted for by the inflammatory changes in the sensitive laminæ and the papillæ of the keratogenous membrane generally, for it follows as a matter of course that these tissues, themselves in a diseased condition, must naturally produce a horn of a greatly altered and inferior quality.

When following the _subacute_ form of laminitis, the changes characterizing pumiced-foot are slow in making their appearance. The animal at first goes short, and the lameness thus indicated gradually becomes more severe, until the animal is no longer able to work. The feet become hot and dry, the hoof loses its circular form, and the growth of horn at the heels becomes excessive. At this stage the appearance of bulging at the sole begins to make itself seen. Later, the outer surface of the wall becomes 'ringed' or 'ribbed,' the rings being somewhat closely approximated in the region of the toe, and the distance between them gradually widening towards the heels. The wall too, especially in the region of the toe, instead of running in a straight line from the coronary margin to the shoe, becomes concave. It is this change, together with the appearance of the rings, that indicates the loosening of the attachment of the os pedis to the wall, and its afterwards backward and downward direction (see Fig. 124).

As a sequel of _acute_ laminitis, these changes make their appearance with more or less suddenness, and are generally complicated in that they owe their occurrence to the formation of pus within the horny box.

_Treatment_.--Pumiced-foot is always a serious condition. The animal is useless for work upon hard roads or town pavings, and is of only limited utility for slow work upon soft lands. The more serious form, that following acute laminitis, and complicated by the presence of pus, we may regard as beyond hope of treatment.

With the more simple form of the condition, we may do much to render greater the animal's usefulness. The same principles as were applied to the shoeing of flat feet will have to be observed here. Trimming or paring of any kind, save 'straightening up' of the wall, must be severely discountenanced. A broad-webbed shoe, one that will give a certain amount of cover to the sole, is indicated. As in the treatment of flat-foot, however, direct pressure upon the sole must be avoided, and the shoe 'seated.' The 'seating,' however, should not commence from the absolute outer margin of the shoe's upper surface. A _flat_ bearing should be given to the wall and the white line, and the seating commenced at the sole.

We have already remarked on the increased growth of horn at the heels. It is in this position, then, that will be found the greatest bearing surface for the shoe, and it is wise, in this case, to have the heels of the shoe kept flat. In other words, the 'seating' is not to be continued to the hindermost portion of the branches of the shoe. By this means there may be obtained at each heel a good solid bearing of from 2 to 3 inches, which would otherwise be lost.

Where the accompanying condition of the horn is bad enough to indicate it, a leather sole should be used, beneath which has been packed a compress of tow and grease, rendered more or less antiseptic by being mixed with tar.

Where the sole is exceedingly thin, and inclined to be easily wounded, and where the hoof, by its brittleness, has become chipped and ragged at the lower margin of the wall, it may perhaps be more advantageous to use, in place of the compress of tow, the _huflederkitt_ of Rotten. This is a leather-like, dark brown paste. When warmed in hot water, or by itself, it becomes soft and plastic, and may readily be pressed to the lower surface of the foot, so as to fill in all little cracks and irregularities, and furnish a complete covering to the sole and frog, and to the bearing surface of the wall. When cold it hardens, without losing the shape given to it, into a hard, leather-like substance.

Treated in this way, the animal with pumiced feet may yet be capable of earning his living at light labour or upon a farm.

E. 'RINGED' OR 'RIBBED' HOOF.

_Definition_.--A condition of the hoof in which the wall is marked by a series of well-defined ridges in the horn, each ridge running parallel with the coronary margin. They are known commonly as 'grass rings,' and may be easily distinguished from the more grave condition we have alluded to as following laminitis, by the mere fact that they do not, as do the laminitic rings, approximate each other in the region of the toe, but that they run round the foot, as we have already said, _parallel with each other_.

_Causes_.--This condition is purely a physiological, and not a pathological one, and the words of its more common name, 'grass rings,' sufficiently indicate one of the most common causes. Anything tending to an alternate increase and decrease in the secretion of horn from the coronet will bring it about. Thus, in an animal at grass, with, according to the weather conditions, an alternate moistness and dryness of the pasture, with its consequent influence on the horn secretion, these rings nearly always appear. The effects of repeated blisters to the coronet make themselves apparent in the same way, and testify to the efficacy of blisters in this region in any case where an increased growth of horn is deemed necessary. From this it is clear that the condition depends primarily upon the amount and condition of the blood supplied to the coronary cushion. Thus, fluctuations in temperature during a long-continued fever, or the effects of alternate heat and cold, or of healthy exercise alternated with comparative idleness, will each rib the foot in much the same manner.

_Treatment_.--The condition is so simple that we may almost regard it as normal. Consequently, treatment of any kind is superfluous. Where constitutional disturbance is exerting an influence upon either the quality or quantity of the blood directed to the part, then, of course, attention must be paid to the disease from which it is arising.

F. THE HOOF WITH BAD HORN.

(_a_) THE BRITTLE HOOF.

_Definition_.--As the name indicates, we have in this condition an abnormally dry state of the horn.

_Symptoms_.--These are obvious. The horn is hard, and when cut by the farrier's tools gives the impression of being baked hard and stony, the natural polish of the external layer is wanting, and there is present, usually, a tendency to contracted heels. With the dryness is a liability to fracture, especially at points where the shoe is attached by the nails. As a consequence, the shoes are easily cast, leading to splits in the direction of the horn fibres. These run dangerously near the sensitive structures, giving rise in many cases to lameness. Even where pronounced lameness is absent the action becomes short and 'groggy,' and the utmost care is required in the shoeing to keep the animal at work.

_Causes_.--To a very great extent the condition is hereditary, and is observed frequently in animals of the short, 'cobby' type. In ponies bred in the Welsh and New Forest droves the condition is not uncommon, especially in the smaller animals. Animals who have had their feet much in water--as, for instance, those bred and reared on marshy soils--and afterwards transferred to the constant dryness of stable bedding, are also particularly liable to this condition. It is noticed, too, following the excessive use of unsuitable hoof-dressings, more especially in cases where coat after coat of the dressing is applied without occasionally removing the previous applications.

_Treatment_.--As a prophylactic, a good hoof-dressing is indicated. It should not consist solely of grease, but should have mixed with it either wax, turpentine, or tar.

Above all, careful shoeing should be insisted on, and the owner of an animal with feet such as these will be well advised if he is recommended to have the shoeing superintended by one well competent to direct it rightly. The foot should be trimmed but lightly, always remembering that in a foot of this description the horn, in addition to being brittle, is generally abnormally thin. Jagged or partly broken pieces should be removed, and the bearing surface rendered as level as possible. The foot should be carefully examined before punching the nail-holes in the shoe, and the nail-holes afterwards placed so as to come opposite the soundest portions of horn. The nails themselves should be as thin as is consistent with durability, and should be driven as high up as possible.

On the least sign of undue wear the shoes should be removed, never, as is too often done, allowing them to remain on so long that a portion breaks away. If, with the laudable idea of not interfering with the horn more than is possible, this is practised, the portion of the shoe breaking off is bound to tear away with it more or less of the brittle horn to which it is attached.

Where the breaks in the horn are so large as to prevent a level bearing for the shoe being obtained, the interstices should be filled up with one or other of the preparations made for this purpose. One of the most suitable is that discovered by M. Defay. By its means sand-cracks or other fractures of the horn may be durably cemented up.

'Even pieces of iron may be securely joined together by its means. The only precaution for its successful application is the careful removal of all grease by spirits of sal-ammoniac, sulphide of carbon, or ether. M. Defay makes no secret of its composition, which is as follows: Take 1 part of coarsely-powdered gum-ammoniac, and 2 parts of gutta-percha, in pieces the size of a hazel-nut. Put them in a tin-lined vessel over a slow fire, and stir constantly until thoroughly mixed. Before the thick, resinous mass gets cold mould it into sticks like sealing-wax. The cement will keep for years, and when required for use it is only necessary to cut off a sufficient quantity, and remelt it immediately before application. We have frequently used this cement for the repair of seriously broken hoofs. It is so tenacious that it will retain the nails by which the shoe is attached without tearing away from the hoof.'[A]

[Footnote A: _Veterinary Journal_, vol. iii., p.71.]

Failing this, the bearing surface may be made level, and fractures repaired by using the _huflederkitt_ described in the treatment of pumiced sole.

(_b_) THE SPONGY HOOF.

_Definition_.--This is the opposite condition to the one we have just described, and is characterized by the soft and non-resistant qualities of the horn.

_Symptoms_.--Spongy hoof is quite common in animals that have large, flat, and spreading feet--in fact, the two appear to run very much together. It is a common defect in animals reared in marshy districts, and of a heavy, lymphatic type. The Lincolnshire Shire, for instance, has often feet of this description, and, the causative factors being in this case long-continued, render the feet extremely predisposed to canker. The horn is distinctly soft to the knife, and has an appearance more or less greasy. Animals with spongy feet are unfit for long journeys on hard roads. When compelled to travel thus, the feet become hot and tender, and lameness results. A mild form of laminitis, extending over a period of three or four days, often follows on this enforced travelling on a hard road, more especially in cases where the animal is 'heavy topped,' and the usual food of a highly stimulating nature. In fact, it has been the author's experience to meet with this condition several times in the case of shire stallions doing a long walk daily upon hard roads, with the weather hot and dry.

_Treatment_.--When a horse with spongy feet is shod for the first time, care must be taken to avoid excessive paring of the sole, for already the natural wear of the foot has been sufficient to keep the soft horn in a state of thinness. For the same reason hot fitting of the shoe must not be indulged in for too long a time. That common malpractice of the forge, 'opening up the heels,' must, in this case, be especially guarded against, or the excessive paring of the frog and partial removal of the bars that this operation consists in will lay the foot open to risk of contraction. To begin with, the heels are naturally weak, and, once the bars are removed, there is nothing to prevent them rapidly caving in towards the frog. Even when carefully shod, a foot of this class is readily prone to contract directly the animal is brought into the stable, and the horn commences to dry to excess. An ordinary light shoe should be used, and the nails should be light and thin. They should be driven carefully home, and the 'clinching' made as tight and secure as possible.

G. CLUB-FOOT.

_Definition_.--Under this name we indicate all cases in which the horn of the wall become straightened from above to below. It will, therefore, include all conformations varying from the so-called 'upright hoof,' in which the toe forms an angle of more than 60 degrees with the ground, to the badly 'clubbed' foot, in which the horn at the toe forms a right angle with the ground, or is even directed obliquely backwards and downwards, so that the coronary margin overhangs the solar edge of the wall.

_Symptoms_.--Even in its least pronounced form the condition is apparent at a glance, the alteration in the angle formed by the hoof with the ground striking the eye at once, and the heels, as compared with the toe, appearing much too high. When the condition is slight, the wall of the toe is about twice as high as that of the heels, while in the most marked form the toe and the heels may in height be nearly equal (see Fig. 83). When congenital, but little interference with the action is noticed. Such animals, by reason of their 'stiltiness,' are unfit for the saddle, but at ordinary work will perform their duties equally well with the animal of normal-shaped feet. When acquired as the result of overwork, of contracted tendons, or other causes, however, the gait becomes stumbling and uncertain. The body-weight is transferred from the heels to the anterior parts of the foot, and the shoe shows undue signs of wear at the toe.

_Causes_.--Upright hoof is undoubtedly hereditary, and is even seen as a natural conformation in the feet of asses and mules. When hereditary in the horse, however, it is certainly a defect, and is associated commonly with an upright limb, and a short, upright pastern (see Fig. 83).

Among other causes, we may enumerate sprains or wounds of the flexor tendons, or any disease of the limbs for a long time preventing extension of the fetlock-joint, such as sprains or injuries of the posterior ligaments of the limb, splints or ringbones so placed as to interfere with the movements of the flexor tendons, or, in the hind-limb, spavin, keeping for some months the fetlock in a state of flexion. In the very young animal the condition may be induced by an improper paring of the foot--cutting away too much at the toe, and allowing the heels to remain.

_Treatment_.--When the condition is congenital, no treatment at all is indicated. It might, in fact, be said that interference would tend rather to minimize than enhance the animal's usefulness; for, in this case, the club-shaped feet are in all probability due to faulty conformation above. In other words, the upright hoof is in this instance but a natural result of the animal's build, with which useful interference is impossible.

Where the upright hoof is a consequence of excessive paring of the toe, or insufficient removal of the heels, the condition may be remedied by directing attention to those particulars, and preventing their continuance. At the same time, a greater obliquity of the limb axis may be given by the use of a suitable shoe. The shoe indicated is a short one, with thin heels and a thick toe. In some cases the abnormality may be remedied by the use of a tip. Whatever method is adopted, care must be taken not to attempt too positive a change in the direction of the limb at one operation. The process must be gradual.

In cases where the abnormality has been brought about by wounds to the flexor tendons, the alteration in the direction of the limb is often so great as to produce 'knuckling over' of the fetlock. This, to a very great extent, may be remedied by the use of a shoe with calkins and an extended toe-piece (see Fig. 84).

With this shoe a certain amount of forced exercise is advisable, and at intervals of about two weeks the calkins should be somewhat lowered, until the heels are brought as close to the ground as is possible. In giving directions for this shoe to be made the veterinary surgeon must, when referring to the length of the toe-piece, be guided entirely by the condition of the case. Ordinarily, a suitable length is from 3 to 4 inches. It is necessary also to warn the owner that, by reason of the length projecting, the shoe is liable to be torn off.

Should the 'knuckling over' have become complicated by bony deposits round the seat of the original injury, then a favourable modification of the condition is not so likely to result.

The benefit to be derived from the shoe with an extended toe-piece in a case of excessive knuckling is admirably shown in a brief report of a case, under the title of 'Hooked Foot,' in vol. xiv. of the _Veterinary Record_, p. 716:

'An eighteen months' old filly showed a deformity of the third phalanx, resulting in her walking with the front face of the hoof on the ground. The flexors were apparently all right, and the bending back seemed to be due to contraction of the ligaments of the joint and the sheath of the perforans.

'On the ground of absence of contraction of the flexors, or atrophy and paralysis of the extensors, the surgeon considered the lesion curable by simple orthopædic measures. By means of an elongated toe-piece to the shoe and calkins, which were shortened every fifteen days, the filly was completely cured in seventy days.'

H. THE CROOKED FOOT.

(_a_) THE FOOT WITH UNEQUAL SIDES.

_Definition_.--The foot thus affected has one side of the wall higher than the other.

_Symptoms_.--This deformity is the better recognised when the foot on the floor is viewed from behind. In addition to the difference between the height of the inner and outer heel is seen at once a deviation in the normal direction of the horn. That of the higher side is distinctly more upright than that of the lower, and runs from above downwards and inwards towards the axis of the foot, while the horn of the lower side maintains its normal direction of downwards and outwards.

From what we have said before on contracted foot, this bending in of the wall of the upright side will at once be recognised as a form of contraction. It is, in fact, contraction confined to one-half of the foot only, and, as a result, the upright side of the crooked foot is prone to the troubles arising from that condition. Corns are frequent, and atrophy of that half of the frog on the affected side supervenes. With the inflammatory changes accompanying these conditions we find the horn of the affected side deteriorating in quality. It becomes dry and brittle, and extremely liable to sand-crack. At the same time, thrush of the contracted frog begins to make its appearance.

_Causes_.--More often than not this condition is a result of the conformation of the limb. According as the build above inclines the animal to 'turned in' or 'turned out' toes, so shall we have feet with a wall crooked inwards or crooked outwards; and it may be mentioned here that the evil results inflicted on the foot by ill-shaped limbs above will make themselves the more readily noticed when the animal comes to be shod for any length of time. So long as a natural wear of the foot is allowed, so long does it accommodate itself to the form of limb above. So soon, however, as the shoe is applied, and a more or less equal (and in this case harmful) wear by that means insisted on, so soon does this abnormal change in the height and direction of the horn fibres begin to make itself seen.

While arising in the majority of instances from faulty conformation of the limb, crooked feet may also be brought about by bad shoeing, or by unequal paring of the foot, and, in a few cases, from unequal wear of the foot in a state of nature.

_Treatment_.--Although it may be taken as a rule that lowering of the higher wall, even if persisted in at every shoeing, will do nothing towards remedying the primary cause (viz., the evil conformation of the limb), yet it will serve to keep the condition within reasonable limits. In this case, while removing so much of the wall as is deemed necessary, care must be taken to leave uncut the sole and the bar. Leaving these intact gives us two natural and very potent protections against the contraction already mentioned as impending.

Where, by reason of the thinness of the horn or other causes, sufficient paring to equalize the tread cannot be practised, then the same end may be arrived at by the use of special shoes. That branch of the shoe applied to the half of the foot with the lower wall should be thickened from above downwards. Or, on the same branch, may be turned up a calkin of sufficient height for the purpose. Of the two methods the first is preferable.

In any case, whether depending upon paring, or upon the use of a special shoe, the animal should be sent to the forge quite often, for it is only by a well-directed, and therefore constant, application of the principles here laid down that improvement may be brought about.

When marked contraction of one-half of the foot is present, it will be best treated with the expanding shoe of Hartmann, already described in the section of this chapter dealing with contracted heels (see Fig. 76).

(_b_) THE CURVED HOOF.

_Definition_.--The hoof with the wall of one side convex, and that of the opposite side concave. Fig. 85, showing the foot in section from side to side, gives an exact idea of this malformation.

_Causes_.--As was the case with the condition previously described, this abnormality finds its primary cause in an unequal distribution of weight due to vice of conformation in the limb above, causing one side of the hoof to be higher than the other. As a result of this, the wall that is inordinately increasing in height commences to bulge outwardly (Fig. 85, _a_), while the opposite (Fig. 85, _b_) becomes concave.

The same state of affairs may be occasioned in the forge by leaving one side of the foot too high, and subjecting the other to excessive paring for several consecutive shoeings.

_Treatment_.--In the main this condition may be regarded as a long-standing and aggravated form of the foot with unequal sides. We may say at once, therefore, that it is not so easily remedied as that simpler defect; that, although identical principles will be followed in its treatment, cure must be a matter of some considerable time.

Again, we must look to successive parings of the wall of the higher side to bring about a gradual return to the normal. At the same time, the tendency to contraction of that side is counteracted by shoeing wide, and, if necessary, giving to the upper surface of that branch of the shoe what we have termed elsewhere a 'reversed seating'--viz., an incline of its upper surface from within outwards.