This condition is commonly the result of a severe and jagged tread with the calkin, and takes the form of an ulcerous and excessively granulating wound. As time goes on the granulations become hard and horny-looking, and their fibrous tissue as hard and unyielding as tendon or cartilage.
These if treated in the early stages with repeated dressings of caustic, or, if very exuberant, the use of the knife, usually yield to treatment. If neglected until the condition depicted in the figure is arrived at, then treatment, as a rule, is of no avail. Neither is treatment of any use if any great loss of the coronary cushion has occurred.
D. FALSE QUARTER.
_Definition_.–False quarter is the term applied to that condition of the horn of the quarter in which, owing to disease or injury of the coronet, the wall is grown in a manner that is incomplete.
_Symptoms_.–This condition of the foot appears as a gap or shallow indentation, narrow or wide, in the thickness of the wall, with its length in the direction of the horn fibres. By this we do not mean that the sensitive laminae are bared and exposed. Horn of a sort there is, and with this the sensitive structures are covered. Running down the centre of the incomplete horn is usually a narrow fissure marking the line of separation in the papillary layer of the coronary cushion, which, as we shall later see, is responsible for the malformation.
On either side of the indentation, as if wishing to aid further than ordinarily it should in bearing the body-weight, the horn takes on an increased growth, and stands above the level of the horn surrounding it. It may, as perhaps it really is, be regarded as a form of hypertrophy, brought about by the increased work that the loss of substance in the region of the false quarter puts upon it.
So long as the sensitive structures are protected the animal remains sound. Sometimes, however, from the effects of concussion or of the body-weight, a fissure appears in the narrow veneer of horn that covers them. Into this, which, of course, is but a form of sand-crack, gravel and dirt penetrate, and so set up inflammatory changes in the keratogenous membrane. As a result suppuration ensues, and the animal is lame.
_Causes_.–False quarter may result from any disease of the foot that involves destruction of a portion of the coronary cushion. As we may see from a reference to Chapter III., it is from the papillae of this body that the horn tubules of the wall are secreted. Destruction of any portion of it necessarily results in a corresponding loss of horn in that position. The disease occasioning this more often than any other is perhaps quittor. It may also result from suppurating corn, from a severe tread or overreach, or from the effects of a slowly progressing suppurating coronitis.
_Treatment_.–A radical treatment of false quarter is not to be found. Once destruction of the secreting layer of the coronary cushion has occurred, the appearance of the fissure in the wall will always have to be reckoned with. A false quarter, therefore, not only renders the horse liable to occasional lameness, but also renders weaker that side of the hoof in which it occurs.
The only method of treatment that can be practised, therefore, is that of palliation. Seeing that the trouble the veterinary attendant will have to deal with is loss of a portion of the weight-bearing surface, his attention is immediately directed to the shoeing. As with sand-crack, so with false quarter, the frog and the bars must be called upon to take more of the body-weight than commonly they do with the ordinary shoe. The indication, then, is a bar shoe. At the same time, the bearing of the wall on the shoe on either side of the fissure should be eased by slightly paring it, and the hypertrophied horn on the outer surface of the wall removed with the rasp.
In cases where penetration of the sensitive structures has occurred, complicated with the formation of pus, the same treatment as for complicated crack is to be followed. The foot should be poulticed for several days with hot antiseptic dressings, and thorough cleansing of the infected parted brought about. Afterwards strong solutions of suitable antiseptics should be applied daily until such time as the horny covering has renewed itself. This done and the bar shoe applied, the fissure may be plugged with any effectual stopping. Either a mixture, such as Percival’s, of pitch 2 parts, tar 1 part, and resin 1 part, melted and mixed together, or one of the artificial hoof-horns may either be used with advantage.
E. ACCIDENTAL TEARING OFF OF THE ENTIRE HOOF.
_Causes_.–Seeing that this accident to, and consequent severe wounding of, the keratogenous membrane nearly always occurs in but one way, it is worthy of special mention. So far as we are able to ascertain, it is an accident peculiar to horses continually engaged in shunting operations either in pits or station-yards. At the moment the animal is released from the waggon he has been pulling, and should turn to the right or the left in order to allow it to pass him, the shoe either becomes wedged in between two converging rails, or is trapped by the wheel of the waggon. Either the approaching waggon with the added weight its impetus gives it then pushes the animal suddenly away, leaving a part of his foot still fixed to the rails, or the animal himself, feeling securely held, makes a sudden effort to release himself, and draws his foot cleanly out of the imprisoned horny box.
The author calls to mind a case in which entire removal of the horn of the foot of an ox occurred through the passing over it of the wheel of a heavily-laden cart. It is therefore quite conceivable that the same accident might occur to the horse. As a matter of fact, we find one case on record where one-half of the horny box was thus removed.[A]
[Footnote A: _Veterinary Record_, vol. xiii., p. 129.]
So far as we are able to gather, it is more a result of imprisonment of the shoe than of the foot. It appears, further, to be always a result of the animal being newly shod, and the clinches firmly secured; so much so that it would be probable, with imperfectly secured clinches, that the animal would draw the hoof from the clinches and the shoe rather than the foot from its horny covering.
Therefore, as the author of one of the cases we shall afterwards relate suggests, it should be proposed as a preventive that the shoe-nails of animals regularly engaged in work on the metals should not be clinched in the regulation manner, but should have their points merely screwed off, and the nails afterwards rasped level with the wall.
These cases are particularly interesting as illustrating the rapid manner in which a new hoof is afterwards formed, and the way in which the exposed sensitive laminae take their share in adding to, though not forming the bulk of, the horn of the wall.
From the cases we are able to record it will be seen that this accident need not be looked upon as fatal, nor the injury itself beyond hope of repair. Dependent largely upon the temperament of the animal, the amount of pain that is caused, and the way in which the animal bears it, recovery may be looked for. Even from the very commencement of the accident, however, the pain may be so acute and the animal so violent with it that slaughter becomes necessary.
_Treatment_.–This consists in applying an antiseptic and sedative dressing to the injured parts (for example, Carbolized Oil and Tincture of Opium, equal parts) and afterwards bandaging.
From the only data we are able to work on, it appears that this dressing should be repeated daily, the bandage being removed, each time, the foot well bathed in warm water, and the dressing and bandage afterwards replaced. On first sight, it would appear that once cleansed and bandaged the dressings might be left _in situ_ for several days. Seeing, however, that suppuration, if once set up, would add further to the intense pain the animal is already suffering, and considering the always constant exposure of the foot to infection, it is perhaps wise to persist in daily changing of the dressings.
At the same time, the general health of the animal should be attended to. Suitable febrifuges should be administered, either in the shape of a dose of physic, or salines and liq. ammonia. acetatis; and the pain, if appearing unbearable, allayed by doses of choral and hypodermic injections of morphia.
_Recorded Cases_.–1. ‘A short time ago I was called to see a horse which had had his hoof torn off in a railway “point.” When I arrived at the stable the injury had been done two hours, and the horse had been led from the railway to a loose-box nearly half-a-mile off. On going to this box I was surprised and horrified to find the poor animal mad with pain, rolling and dashing himself about. When on his back he would struggle and kick the walls with the injured foot, as though unconscious of pain. Not one moment was he still, and as I could see that the sensitive structures were much damaged by his violence, I obtained a gun and put him out of his pain.
‘The accident happened in this way. The horse was employed in shunting coal-waggons, and had just drawn four loaded trucks up to a point at which they diverged to the left, and the horse, being unhooked, ought to have turned to the right. Here, unfortunately, the near fore-foot became wedged in between two converging railway plates, one of which formed a part of the waggon-way, on which the trucks were running. The horse was a big animal, and freshly shod with heavy shoes, on which a toe-piece and calkins were used. The shoe was roughly but strongly nailed on with eight nails, the clinches of which were all firm. This shoe was fitted wide at the heels, and when the foot was fixed in the points (toe downwards) it protruded over the face of the rail. When the trucks reached it they pressed it down, and, the horse leaning forward, the hoof was drawn off like a glove. The hoof was almost as clean inside as if taken off by maceration–only towards the toe was a small portion of the coffin-bone and some torn laminae left inside the hoof.
‘As soon as possible after the accident, so I was told, the foot was bound up with tow and a bandage; then a sack was cut up and placed over all, and the horse slowly led to his loose-box. He “carried” the leg all the way, limping along on the three sound ones. Almost immediately after reaching the box he lay down, but only for a short time. The standing position was not long maintained–profuse perspiration set in, and the alternations of position became more rapid and violent, till plunging and rolling were added to the other signs of excruciating pain. I was also told that the groaning of the poor animal was almost constant, and at times so loud and prolonged as to amount to a shriek.
‘I have no experience of a similar case, and I should not have supposed that this accident would have caused such acute suffering and violent symptoms. I think I have heard of such cases making a complete recovery; but I feel sure that, in this case, I only anticipated death by, at most, a few hours.'[A]
[Footnote A: _Veterinary Record_, vol. iv., p. 127.]
2. ‘The case I am about to give you an account of, being one of rare occurrence, I thought would not prove uninteresting to the members of the Veterinary Medical Association. It is an instance of complete removal of the hoof by mechanical force.
‘Our patient was a brown mare, five years old, the property of Messrs. Crawshaw and Co., railway contractors on the Sheffield and Manchester line.
‘On June 20 the mare was, as usual, working on the line, drawing one of the waggons for the removal of soil from one place to another, and, as was the custom, the pace is generally increased at about the distance of from sixty to eighty yards from where the unloading takes place, in order to add to the velocity, so that the contents of the waggons might roll down so great a precipice. It was at this increased action, when the mare was being removed from the waggon, that she stepped between the ends of two iron rails, sufficiently apart to admit the foot only, when one end of the rail inserted itself between the sole and toe of the shoe, the other at the top and in front of the crust.
‘The mare, finding herself fixed, endeavoured to disengage herself, and, in doing so, got in front of the waggon, which, coming at a great pace, forced her down into the pit, leaving behind the off fore-hoof, which was only removed from its situation between the two rails by a large hammer, it being so firmly wedged in. The shoe and hoof were bent in a very peculiar manner, as the accompanying cuts will show, the inside heel being completely raised from above the level of the frog, not one of the nails being unclenched, or in the slightest degree having given way to so large an amount of force imposed upon them, although the toe of the shoe was raised from the sole by the rail being immediately under it (see Fig. 114). The mare had been shod the day before, and, having a good sound foot, the shoe was firmly put on.
‘Being a mile from home, she was with some difficulty made to travel that distance. On her arrival, my preceptor, Mr. Taylor, was immediately sent for, who found her, as I have before stated, with the off fore-foot hoofless.
‘Proceeding to examine the foot, he ascertained that it had bled considerably, which, however, was stopped by bandages to the foot and a ligature round the coronet. The laminae on one side and a small portion of the sensitive sole, though not to any great extent, were lacerated. The coffin-bone was not at all injured. The bleeding having nearly ceased, she was put into slings, the foot carefully washed with warm water, and immediately bound up with pledgets of tow saturated with the simple tincture of myrrh and tincture of opium, of each equal parts.
[Illustration: FIG. 114.–HOOF TORN FROM THE FOOT BY ACCIDENT.]
‘The dressing was ordered to be allowed to remain on all night, and on the following morning to be removed. The foot was then bathed, as before, in warm water, and the application of the tinctures repeated night and morning. The medicine internally given was castor oil, with tinct. opium, and this, in a diminished dose, was ordered the next morning. Blood was also abstracted from the jugular vein, to the amount of 6 quarts, so as to allay the inflammatory fever set up. The food consisted of bran and linseed, with small portions of hay and water. The mare being in a highly excited state, and suffering such severe pain, the opinion Mr. Taylor gave was that, should she get over the first four days (which appeared quite uncertain), he had no doubt of her ultimately getting well, and also that she would have a perfect hoof formed. It was now left for the owners’ consideration, whether they thought the mare worth her keep till such took place, the time mentioned by Mr. Taylor being four or five months. She was seen again the fourth day after the accident, and was then found to be perfectly tranquil and feeding well; her pulse, which at the first visit could not be counted, was now not more than 65 beats in the minute. On removing the dressings, the foot presented a very favourable appearance, the treatment therefore varied only in the application of a linseed-meal poultice over the former dressings of tinctures of opium and myrrh, confining the whole in a soft leather boot. Diet as before, in addition to which give a few oats. Should the bowels become constipated, repeat the castor oil without the opium.
‘_June_ 28.–The animal was again seen, and appeared to be going on very favourably. The poultices were directed to be discontinued, and the parts dressed every other day with sol. sulph. cupri, as the granulations were getting rather luxuriant.
‘_July_ 6.–To-day she was found to have gone on so well, having two days before been removed from the slings, that it was thought justifiable to turn her out, protecting the foot with a boot, and ordering the dressings to be repeated.
‘_July_ 23.–She was seen by me in the field, where I had the boot removed, and so much had she improved, that not less than 2 inches of crust, proceeding from the coronary ring, had been formed, and the foot looked remarkably healthy.
‘It will be seen that the accident occurred on June 20, a fortnight after which time I observed the horny crust to be forming from the coronet, and the insensitive laminae at the same time, in which on every visit an increase of growth was perceptible, and it soon attained a thickness exceeding that of the other hoof, but which at the same time presented a more upright appearance. It was not until three weeks after our first visit that any formation of new sole or frog was to be seen. Of the two the sole was the first, being secreted by the sensitive sole, the growth proceeding from the heels. In like manner the insensitive frog was being produced by the sensitive.
[Illustration: FIG. 115.–HOOF TORN FROM THE FOOT BY ACCIDENT.]
‘During the last week in October the mare, having her foot protected with a bar shoe plated at the bottom, and so formed as to open without necessity of removing the shoe, in order to facilitate the applications of the tinctures, was put to light work, which has since been gradually increased, and she now performs her usual labour equal to any other horse.
‘The growth of the wall or crust and insensitive laminae is not yet quite complete, nor is the sole, there being wanting about an inch of the horny substance of it, the entire completion of which I should rather doubt, as I mentioned in my former communication that the sensitive laminae and a small portion of the sole were lacerated, and it is in these parts that the imperfections exist.
‘The yet imperfectly-formed wall not admitting of the insertion of nails all around it, the shoe is held on partly by nails and partly by a strap attached to it bound round the coronet.'[A]
[Footnote A: _Veterinary Record_, vol. iv., p. 182 (B. Cartledge).]
3. ‘This case is related by Mr. A. Rogerson, F.R.C.V.S. It occurred to an animal regularly engaged in shunting, and happened through the corner of the shoe becoming “trapped” between a line of metal and the wheel of a truck. It is particularly interesting on account of the photograph accompanying it, and which we here reproduce in Fig. 115.
‘The photograph shows plainly the manner in which the holding of the “clinches” on the left side of the hoof has resulted in drawing it off from the foot. Had these clinches, as Mr. Rogerson suggests, been left unfastened, then the accident in all probability would not have occurred. The animal was destroyed.'[A]
[Footnote A: _Ibid_., vol. xiii., p. 2.]
CHAPTER IX
INFLAMMATORY AFFECTIONS OF THE KERATOGENOUS APPARATUS
A. ACUTE.
ACUTE LAMINITIS.
_Definition_.–The term ‘laminitis’ is used to indicate a spontaneous and diffuse inflammation of the whole of the sensitive structures of the foot, more particularly the sensitive laminae. Usually it occurs in the two front feet, often in all four, and occasionally in the hind alone.
_Causes_.–In dealing with the causes of laminitis, we will first dispose of those coming under the heading of _traumatic_. Correctly speaking, however, lesions of the laminae thus occurring do not present the same symptoms, nor run an identical course with the disease we now purpose describing, and for which we would prefer to entirely reserve the term ‘laminitis.’ The fact, however, that traumatic causes are detailed in other works on the same subject compels us to give them mention here.
Strictly traumatic causes giving rise to a limited inflammation of the sensitive laminae are violent blows upon the foot, either purely accidental, or self-inflicted by violent kicking.
A similar limited laminitis is to be found in the conditions we have described under ‘Nail-bound and Punctured Foot.’ It is met with also in the injuries resulting from tread and overreach, and in the tissue-changes accompanying corn.
The tenderness following upon excessive hammering in the forge, or of too long an application of the shoe in hot-fitting has also been described as laminitis.
With either of the conditions we have mentioned, it goes without saying that there is either a simple congestion or an actual inflammation, localized or general, of the laminae of the injured foot. In neither case, however, can the resulting mischief be closely compared with the lesions attending an attack of laminitis proper, a disease which appears to have an almost specific cause, and to run a course peculiarly its own.
The specific cause we have indicated as existing can, in the present state of our knowledge, be only vaguely described as a poisoned state of the blood-stream. This, as clinical evidence teaches us, may result from a variety of causes.
Among these, by far the most common is that state of the circulation induced by excessive feeding with too stimulating or too irritating a diet. In any case, where the use of old oats as a staple diet is departed from, and where the quantity and manner of using the substitute is left to the discretion of careless or unskilled attendants, trouble is likely to ensue. The food more prone, perhaps, than any other to bring about an attack is wheat improperly prepared–that is, uncooked or unground. So much so is this the case that one full meal of this provender to an animal unused to it is sufficient to lead to a train of symptoms often ending fatally.
Beans, peas, barley, rye, new maize, or even new oats, are all liable, if carelessly used, to have the same effect.
It is the laminitis following feeding on new oats that has caused us to apply to the food the adjective ‘irritating.’ Here, more often than not, the peristaltic action of the bowels is found to be abnormally in evidence, and the excessive use of the diet is always accompanied by a more or less fluid discharge of the intestinal contents.
In addition to the foods we have mentioned, many others might be enumerated, more especially the numerous ‘made-up’ feeding materials now on the market. Many are composed of substances that may be regarded as absolutely opposed to the correct feeding of a horse, and their use can only be followed by this and other evil results.
Another most fruitful cause of laminitis is a severe and continued inflammatory condition of the system elsewhere. It is the laminitis known to veterinary surgeons as ‘metastatic,’ and perhaps the two most notable examples of it are the laminitis following a prolonged attack of pneumonia, and the ‘Parturient Laminitis’ occurring as a concomitant of septic metritis.
Parturient laminitis it is that offers us the most striking illustration of the truth that a poisoned state of the blood-stream is a sure factor in the causation of an attack. From the direct evidence of our senses (namely, manual exploration of the infected womb, and the stench of the exuding discharge) we know that we have in the interior of the womb matter in a state of putrescence. From the experience of previous post-mortems we know, further, that the putrescent matter thus originating often gains the blood-stream, and forms foci of septic lesions elsewhere–liver or lung. When, therefore, during an attack of septic metritis a condition of laminitis supervenes, we are justified in attributing it to the escape of septic matter from the already infected uterus.
In the same category of laminitis from metastasis may also be placed the laminitis occurring as a result of an overdose of aloes. The enteritis thus set up is often followed by laminitis, and that of a serious type.
Prolonged and excessive work upon a hard road is also apt to induce an attack. When this occurs it in many cases resolves itself into a case of cruelty. (See reported case, No. 1, p. 279.)
Laminitis from this cause was frequent among coach and carriage horses in the pre-railroad period, and resulted from attempting to obtain from the animal a faster pace and a greater number of miles than he was physically capable of giving.
In our day, however, it is more often a result of gross feeding, combined with only that amount of work which the horse, if ordinarily fed, would be easily able to perform. An excellent example of this is the laminitis occurring in the Shire stallion when commencing his rounds of service in the spring and early summer. At this season these animals are constantly supplied with a more than sufficient supply of a highly stimulating and nutritious diet. In this case the blood is already in that state in which it is predisposed to the disease. Add to this the unwonted exercise–for during all the winter the animals are idle–and congestion of the venous apparatus of the extremities is not to be wondered at.
Passing from these, the more common, we may consider other and less frequent causes of the disease. Congestion of the laminal blood-vessels and consequent laminitis occurs when animals are made to maintain a standing position for prolonged periods, as, for instance, when making sea voyages. A long and painful disease of one foot, necessitating the whole of the weight being borne by the other, ends often in laminitis of the second member. It may thus occur as a sequel to quittor, complicated sand-crack, suppurating corn, and punctured wounds of the feet.
Laminitis has also been known to occur as a result of septic infection of the blood-stream consequent on the operation of castration. (See recorded case, No. 2, p. 281.)
A sudden lowering of the surface circulation at a time when the animal is excessively perspiring is also said to favour an attack, as also is the giving to drink of cold water to an animal just in from a long and tiring journey. Also, according to Zundel, ‘the influence of the season cannot be denied, and it is during the summer months that laminitis is more frequent, while it is rare in winter, as well as in the spring and autumn.’
Further, laminitis has been described as occurring when the animal is at grass, and when all causes–at any rate, active ones–have appeared to be absent. (See reported case, No. 3, p. 282.)
Regarding heredity, we may safely say that, as a cause of laminitis, it may be almost totally disregarded. That a bad form of foot, either a flat-foot or a foot with heels contracted, and already thus affected with a mild type of inflammation, did not offer a certain predisposition, we should not like to assert. There must, however, be an exciting cause–namely, a poisoned condition of the blood-stream. This latter cannot, of course, be in any way regarded as hereditary.
In short, the dietetic cause is by far the most common, and, in prosecuting inquiries as to the starting-point of an attack, the veterinarian’s attention should be directed in the main to that particular.
_Symptoms_.–Laminitis is always ushered in by a set of symptoms indicative of a high state of fever. The pulse is raised from the normal to as many as 80 or 90 a minute, muscular tremors are in evidence, the respirations are short and hurried, and the temperature rises to 105 deg., 106 deg., or 107 deg. F. The visible mucous membranes are injected, that of the eye, in addition to the hyperaemia, often tinged a dirty yellow. The mouth is dry and hot, the urine scanty, and the bowels frequently torpid. As yet, however, the walk is sound.
Called in during this early stage, the veterinarian is often puzzled as to the exact significance of the symptoms. Enteritis, lymphangitis, or pneumonia he knows to be often heralded in the same manner. In this connection, Zundel says: ‘Laminitis, in most instances, is preceded by certain general symptoms, such as are premonitory of the invasions of ordinary inflammatory diseases, but of an uncertain significance.’
So far we agree with him, but to what we have already said we would add that, even in this early stage, there is an additional symptom, unmentioned by Zundel, which often leads one to an exact diagnosis. The feet are in turn lifted a short distance from the ground, and almost immediately replaced. This movement (‘paddling,’ we may term it) is constant, the animal appearing to obtain ease in no one position for more than a few moments at a time.
Seen but a few hours later, when the swelling caused by the hyperaemia and outpouring of the inflammatory exudate has led to compression of the sensitive structures within the horny box, the symptoms presented admit of no misreading, save by the most casual and careless observer. The patient now stands as though fixed to the ground. The pulse is hard and frequent, the respirations tremendously increased in number, the body wet with a patchy perspiration, and the countenance indicative of the most acute suffering. Only with difficulty, and often only at the instigation of the whip, can the animal be induced to move. This he does by throwing his weight, so far as he is able, on to the heels of the feet affected, and putting the feet slowly forward in a shuffling and feeling manner. The feet themselves give to the hand a sensation of abnormal heat, percussion upon them with the hammer is followed by painful attempts at withdrawal, while any effort we may make to remove one foot from the ground is useless, so great an aversion does the animal show to placing a greater weight upon the opposite foot.
According as the front-feet alone, the hind-feet alone, or all four feet are affected, the symptoms will vary.
With all four feet diseased, the animal stands with the two front-feet extended in front of him, while the hind-limbs are at the same time propped as far beneath him as is possible. The horse is, in fact, standing upon the extreme hindermost portions of the feet.
Why the animal should thus distribute his weight is easily explained. Standing in the normal position, the body-weight is borne by the sensitive laminae, the sole, of course, sharing in the burden, but the laminae taking by far the greater part of the pressure thus exerted. With the vessels of the laminae gorged with blood, and the laminal connective tissue infiltrated with a profuse inflammatory exudate, the most excruciating pain is bound to result by reason of the compression of the diseased tissues within the non-yielding structures. In some little measure the suffering animal may afford himself relief by partly removing pressure from the fore-parts of the hoof. When placing the body-weight behind, the pressure, instead of falling upon the highly sensitive laminae, is directed to the follicular and fatty tissues of the plantar cushion: from there, with only a small portion of the sensitive sole intervening, to the horny frog, and from thence to the ground.
The same distribution of weight also places the foot in a position of greatest expansion, thus, by giving greater room to the diseased parts, again affording relief of pressure on the inflamed lamina, while it at the same time relieves of weight the foremost portions of the sensitive sole.
With the fore-feet alone attacked, the animal affects exactly the same position of standing as that just described. The fore-feet are again extended, and the hind propped far beneath him. The fore extended, in order to obtain the relief occasioned by standing on the heels; the hind in this case carried forward in order to take a greater share of the body-weight, and thus relieve the congested members in front.
With the hind only attacked, then the fore and the hind feet are more closely approximated than in the normal position. The reason, of course, is that the hind-feet are carried forward in order to be placed upon the heels, while the fore are taken backwards to relieve the hind of the body-weight.
In like manner the movements of the animal will vary with the feet affected. With only the front-feet diseased the animal is, comparatively speaking, comfortable. The hind-feet take the weight, and the animal stands for long periods together, resting alternately first one fore-foot and then the other, moving often in a circle of which his body is the radius, and his hind-limbs the centre. If urged to move forward, then immediately his countenance and movements manifest the pain to which he is put. Only with reluctance does he cause the fore-feet to take weight. They are shuffled forward quickly one after the other, so that weight may not be placed upon them for one instant longer than is necessary, and the hind-limbs immediately brought again with two short, awkward movements beneath the body. Progress thus takes place in a succession of movements ‘half hobble,’ ‘half jump.’
Painful though this may appear, progress is still more difficult when the hind-feet alone are diseased. Afraid that, in placing his fore-members freely forward, he will add to the pain in his hind, the walk takes place in a series of extremely short steps, with the feet more or less closely approximated. The gait is thus rendered extremely awkward, and Zundel, by saying that ‘the animal appears as if treading on sharp needles,’ most fitly describes it.
Movement with all four feet affected, though less awkward in appearance, is doubtless more painful than in either of the other conditions. Here the animal can hardly be induced to shift his position at all. Only by flogging, and that severe, can he be made to go forward. When so induced to move, the agonizing pain to which the patient is subjected may be gathered by noting his countenance and manner of progression.
With each movement forward, muscular tremors affect the limbs; each step is short, jerky, and convulsive; the respirations and pulse are almost immediately greatly quickened, and the lower lip is hung pendulous, and moved almost unconsciously up and down with a flapping noise against the upper. A patchy perspiration breaks out about the body and quarters, and the tail is outstretched and quivering. At the same time the lines of the face become drawn, the commissures of the lips pulled upwards, the eyes staring and haggard, the eyelids puckered, the nostrils extended, and the whole expression indicative of the intense and agonizing pain of the disease.
One can perhaps better give one’s client some vague idea of the patient’s suffering by likening the pain to the throbbing sensation of a festered finger-nail. Tell him that each hoof of the horse is similarly, or, if anything, more delicately, constructed, that in each foot the same process of ‘festering’ is going on, and that upon them the animal has perforce to stand.
As one might expect, the position of greatest ease is the decumbent. Strange to say, though, in many cases of laminitis the animal persists in maintaining a standing posture. Once down, however, one has sometimes the greatest difficulty in persuading him again to rise. The lying position is so long maintained that bedsores begin to make their appearance, and the animal rapidly loses flesh, not only by reason of the fever and the pain, but by giving to rest the time he should normally give to feeding.
Difficulty in rising is greatest when all four feet are affected; is _nearly_ as great when the hind-limbs only are in trouble, but is least when the disease exists alone in the two fore-feet.
THE COURSE OF THE DISEASE AND ITS PATHOLOGICAL ANATOMY.–As with most inflammations of any severity, so with this we may consider the pathological changes taking place in the foot under three headings: (a) The period of Congestion; (b) the period of Exudation; (c) the period of Suppuration.
(a) _Congestion_.–In the early stages of laminitis there is a state of engorgement of the vessels of the keratogenous apparatus generally, but more particularly the laminal portion of it. With the hoof removed at this stage the sensitive laminae are found to be swollen, dark red in colour, and affording a distinct feeling of increased thickness when pressed between the fingers, Incised, there escapes from the cut surface a large flow of dark venous-looking blood. At this stage haemorrhages of the laminal vessels occur. The escaping blood infiltrates the surrounding connective tissue, and in many cases destroys the union between the horny and sensitive laminae. This change is most noticeable in the region of the toe and the commencement of the quarters, the os pedis appearing as though pushed backwards by the escaping fluid collected between the wall and the bone. In severe cases, fortunately but rarely seen, the blood so escaping continues to infiltrate, and separate the tissues until it is seen to be freely oozing at the region of the coronet. (See reported case, No. 1, p. 279.)
(b) _Exudation_.–The period of exudation marks the outpouring of the inflammatory fluid. This, even more than the haemorrhages attending the stage of congestion, tends to destroy the intimacy between the sensitive and the horny laminae, leading finally to their complete separation at the region of the toe. Fig. 116 illustrates this state of affairs after laminitis has existed for a week. The sensitive and horny laminae are here shown to be distinctly separated from each other, a well-marked cavity existing between them, which cavity is greatest in extent at the toe of the os pedis. With the sensitive structures thus detached from the wall, it is evident that very much that formerly held the os pedis in normal position has been destroyed. What then happens is that the whole of the body-weight is placed upon the sole. Never intended to bear the strain thus imposed, it naturally sinks. With the sinking is a corresponding ‘dropping’ of the pedal bone–in fact, of the whole of the bony column. Seeing that the structures _above_ the hoof are still normally adherent to the bones, it follows that they must, as the os pedis sinks, be carried with it. As a consequence we get a marked depression at the coronet (see Fig. 117, _a_), which depression may be often noticed after the second or third week of a severe attack of the disease.
[Illustration: FIG. 116.–LONGITUDINAL SECTION OF A FOOT WITH LAMINITIS OF EIGHT DAYS’ STANDING. The separation between the sensitive structures and the hoof is indicated by a dark line. The cavity is filled with exudate. It will be noted that as yet there is little change in the position of the os pedis.]
Here, again, though to a greater extent than that caused by the haemorrhage alone, the os pedis appears to be pushed backwards, the space at the toe between the bone and the horny box being closely filled with the yellow, slightly blood-stained exudate. This condition is well depicted in Fig. 117.
[Illustration: FIG. 117.–LONGITUDINAL SECTION OF A FOOT WITH LAMINITIS OF FOURTEEN DAYS’ STANDING. _a_, The depression at the coronet caused by the dropping of the bony column within the horny-box: _b_, a portion of the sensitive sole pushed downwards and forwards by the descending os pedis.]
With the descent of the os pedis we get in many cases a penetration of the horny sole (see Fig. 117), leading always to serious displacement of the sensitive sole (see Fig. 117, _b_), and often to caries of the exposed bone.
The backward displacement of the os pedis may be accounted for in two ways. Firstly, the greater vascularity of the membrane covering its front leads to a greater outpouring of inflammatory fluid in that particular position. Here, therefore, loss of adhesion with the wall is greatest, while into the cavity so formed is poured a large quantity of a fluid that is practically incompressible. The os pedis _must_ be pushed backwards. Secondly, the manner in which the animal distributes his weight–namely, upon the heels–is calculated to aid in the bone’s backward movement, for with his feet in this position tension upon the extensor pedis is relaxed, while that upon the flexor perforans is greatly increased.
(c) _Suppuration_.–Should the animal survive the pain and exhausting calls made upon his system by the accompanying fever of the foregoing conditions, the case ends either in resolution or suppuration. When suppuration occurs it is found, as a rule, at the sole, leading to almost entire separation of the sensitive and horny structures. The pain, if possible, is even worse than in either of the foregoing stages, and relief for the suffering patient is only obtainable by the natural exit of the pus at the coronet, or by giving it escape with the knife at the sole. As a rule, suppuration in laminitis is rare, and then only occurs when the disease has been of some several days’ duration. It has been the author’s experience, however, to meet with it in a case but three days’ old. This particular animal had laminitis restricted to the hind-feet. The condition was diagnosed and pus liberated at the sole of one foot during the third day of the lameness. The animal was cast on the fourth day, and pus obtained from the sole of the opposite foot.
_Complications_.–In a moderate case, carefully treated, laminitis terminates at the end of three or four days in resolution. The general symptoms of fever gradually subside, the appetite returns, and the walk becomes easier. Cases thus terminating fortunately leave behind them no change of serious importance, either in the sensitive tissues or in the horny envelope. Should resolution, however, be longer delayed, then the case, although eventually terminating successfully so far as soundness in gait is concerned, leaves more or less evidence behind in the shape of rings about the wall and alterations in the build of the sole.
When the happy ending of rapid resolution is denied us, then, in addition to the condition we have described as suppuration, we may meet with one or other of the following complications:
_(a) Metastatic Pneumonia_.–This complication is not uncommon, and, when occurring, more often than not ends fatally. It may be accounted for indirectly by the greater work the lungs are called upon to perform in carrying out the increased number of respirations occasioned by the general fever and pain, and directly by the poisonous materials circulating in the blood-stream.
_(b) Metastatic Colic_.–This may be either a subacute obstruction of the bowel or an enteritis accompanied by an offensive purge.
A striking case of the former is related in the _Veterinary Journal_ (vol. xvi., p. 180) by H. Thompson, of Aspatria. Here no evacuation of the bowels occurred for three days, and the pains of laminitis were added to by the usual pains of intestinal obstruction.
The colic of enteritis is in some cases caused by the nature of the food, giving rise to laminitis. In our opinion, however, it is more often occasioned by the drastic action of the aloes nearly always resorted to in the treatment of the disorder. As does the pneumonia, the enteritis thus brought about nearly always has a fatal termination.
_(c) Gangrene of the Structures within the Hoof_.–This complication is the one most to be dreaded. It occurs as a result of the great pressure exerted by an excessive exudation, and doubtless affects first the laminae and softer structures. Once commenced, however, it rapidly extends to death of the other structures (ligament, tendon, and even bone), and gives a fatal ending to the case.
That gangrene of the tissues (“mortification” as our older writers called it) has occurred is soon made evident to the veterinarian by the symptoms shown by the patient. The agonizingly acute pains suddenly subside, the feet are placed firmly and squarely to the ground, and the animal walks with ease. Perhaps but the night before the patient is seen racked with excruciating pain; the morning sees the astounding change of apparent absolute recovery. Too well, however, the eye of the experienced veterinary surgeon sees that such is not the case. Even before proceeding to take a record of the other symptoms, he knows that it is but the commencement of the end. Methodically, however, he notes the other conditions. The pulse he finds small and imperceptible, save at the radial. The thermometer registers a subnormal temperature, the extremities are cold, and cold sweats bedew the body. To the same experienced eye the countenance of the animal is almost suggestive of what has occurred. The drawn and haggard expression, to which we have previously referred, becomes more marked, and the angles of the lips are drawn back in what has been described by some writers as a ‘sardonic’ grin.
We can best express what the whole look of the animal’s countenance indicates to us by saying that it gives us the impression that the animal himself knows that some serious change, and a change fatally inimical to his chances of life, has taken place in his feet.
It may be that in some odd cases, although it has not yet been our lot to meet with them, gangrene may terminate in the casting off of one or more hoofs. Needless to say, there can still be but one termination to the case.
_(d) Periostitis and Ostitis_.–This complication is referred to by other writers under the term of ‘Peditis.’ It signifies, of course, that the periosteum and the bone have become invaded by the inflammatory process. It is our opinion that these two conditions, even including an actual arthritis, always exist, even in an attack of laminitis that ends favourably. We do not claim, however, to be able to relate any means, save that of post-mortem examination, by which it may be singled out from the other changes occurring in the foot. The high fever and pain occasioned by the inroads of the inflammation into the other sensitive structures serves to effectually mask whatever evidence of it we might otherwise obtain. It may be sometimes only small in degree, but we feel confident that inflammation, at any rate of the _outer_ layer of the periosteum, is in laminitis constant even, we repeat, in a mild case.
[Illustration: FIG. 118.–SHOWING CHANGES IN THE OS PEDIS WITH LAMINITIS OF LONG STANDING, (_a_, Viewed from the front; _b_, viewed from the side.) The porous condition of the bone, which is here shown, is a result of a rarefying or rarefactive ostitis. This specimen also illustrated (what the photograph cannot show) an accompanying condition of condensation of bone, or osteoplastic ostitis. (For a fuller description of the changes occurring in these forms of ostitis, see Chapter XI.)]
When the case is a serious one we have ample evidence to show that ostitis exists, and exists in a severe form. The bones become vastly altered in shape, a process of absorption leads to the formation of large, irregular cavities within their substance, and what of the bone is left is rendered hard and ivory-like (condensed) near what was the original centre, while the edges and other portions show often a tendency to become brittle and porous.
Fig. 118 illustrates the effects of a severe ostitis in pedal bones removed from hoofs with laminitis of several weeks’ standing.
_(e) Chronic Laminitis_.–The most common complication–or, perhaps, rather we should term it ‘sequel’–to acute laminitis is the chronic form of the disease. For this condition we have reserved a separate section of our work. It will be found described in Section B 1 of this chapter.
_Diagnosis and Prognosis_.–One is almost tempted to state that the diagnosis of laminitis offers no difficulty. In the very early stages, however, it may, as we have already indicated, be mistaken for the oncoming of Enteritis, Lymphangitis, or even Pneumonia. The paddling of the feet may help us. If this is absent, however, nothing but a most careful examination, or, if necessary, the withholding of our opinion until the following visit will prevent a blunder being made.
Even when well established, laminitis has been mistaken for paralysis, for tetanus, for rheumatic affections of the loins, or even for some undiscovered affection of the muscles of the arms and chest. This latter is no doubt suggested to the uninitiated by the reluctance the animal shows to move the muscles _apparently_ of that region, and led the older writers to give to the disease its name of ‘Chest-founder.’ It is only fair to add, however, that these blunders in diagnosis are nearly always committed by persons without a veterinary training.
Thus warned, the veterinary surgeon of average ability should have no difficulty in establishing a distinction between the diseases we have enumerated as likely to be confounded with it, and the one this chapter is describing.
The prognosis in laminitis should, in our opinion, always be guarded. No advice given in a work of this description can be of any real use, for every case must be judged entirely on its merits. The severity of the symptoms, the cause of the attack, the complications, and the idiosyncrasies of the patient, have all to be taken into account. These the veterinarian must be left to judge for himself.
_Treatment_.–The treatment of acute laminitis in its early stage must be based upon the fact that we have to deal with a congested state of the circulatory apparatus of the whole of the keratogenous membrane. This fact was well enough known to the older veterinarians. It is not surprising, therefore, to learn that jugular phlebotomy was at once resorted to as the readiest means of relieving the overcharged vessels of their blood. As a matter of fact, bleeding from the jugular is still advocated by modern authorities. We cannot say, however, that we unhesitatingly recommend it. Mechanically, of course, the removal of a large quantity of blood is bound to result in a lowering of the pressure in the vessels. The effect, however, is but transient. Blood removed in this way is again quickly returned to the vessels so far as its fluid matter is concerned, and the pressure, removed for a time, is again as great as before. With the other and more vital constituents of the blood-stream–namely, the corpuscles–restoration is not so rapid. We have, in fact, a weakened state of the system, in which it is probable it will not so successfully combat the adverse conditions the disease may induce.
With these prefatory remarks, we may advise bleeding under certain conditions. The quantity removed must be moderate (7 to 8 pints), and the pulse and other conditions must show no signs of weakness or collapse.
Local bleeding, either from the toe or the coronet, is also advised. In the former situation the sole is thinned down until a sufficient flow is obtained, while at the coronet scarification is the method adopted. Bleeding locally, however, is far less effectual than the jugular operation. Neither must it be forgotten that wounds in these situations, more particularly at the toe, are extremely liable, especially with the existing poisoned state of the blood-current, to take on a septic character. What might possibly have remained a comparatively simple inflammation is induced by the operation itself to terminate in the more complicated and serious condition of suppuration.
Other means of combating the congested state of the membrane are principally those of local applications. With many veterinary surgeons warm poulticing is still largely advocated and practised. We do not believe in it. Warmth, as a means of removing local congestion, can only be successful when applied _widely_ round the congested area, and so dilating surrounding bloodvessels and lymphatics. Applied to the congested area itself, and to that alone, it is almost worse than useless.
With the foot, both around and below it, a surrounding area is denied us. The only vessels we are able to dilate with the warmth, and so enable them to carry off the fluid from the congested foot, are those in the limb above. That poulticing cannot be successfully there applied is self-evident. Apart from that, it is an open question whether poultices may not do actual harm in inducing suppuration in cases where, probably, it would not otherwise occur.
For these reasons we hold to the opinion that when a local application is determined on it should be a cold one. Various methods of applying cold are in vogue. Cold swabs are perhaps most in favour. They must, however, be _kept_ cold. When a suitable water-course, pond, or other expanse of shallow water is at hand, then the animal may be kept standing therein, or preferably walked about in it. When suitable apparatus is obtainable, a constant stream over each foot from a rubber hosepipe is most beneficial.
Astringent baths, containing solutions of alum, of copper sulphate, of iron sulphate, or of common salt, or composed of a mixture of two or more of the salts mentioned, may also be used with advantage. In addition to the fact that such solutions are for a time below the temperature of simple water, we have the advantage that they have also a more or less antiseptic property.
While on the subject of the relief of the congestion, we must not forget to mention a treatment which we ourselves have practised with considerable success–namely, that of forced exercise. It appears to have been first brought into prominence by Mr. Broad, of Bath, and the two terms ‘Forced Exercise and Rocker Shoes’ and ‘Broad’s Treatment’ have come to be synonymous.
The Broad shoe is a shoe with a web of quite twice the thickness of the animal’s ordinary shoe, and has this web gradually thinned from the toe backwards until at the heels the shoe is at its thinnest (see Fig. 119).
The excessive thickness of the shoe serves two purposes. It allows of the requisite amount of slope being given to the web, and so enables the animal readily to throw himself back on to his heels, a position in which, as we have already indicated, he obtains the greatest ease. It also minimizes to some extent the effects of concussion.
[Illustration: FIG. 119.–SEATED ROCKER BAR SHOE (BROAD’S) FOR TREATMENT OF LAMINITIS.]
With forced exercise, as practised by Mr. Broad, this shoe is first applied, and the animal afterwards made to walk upon soft ground, or even upon the roadway, for a half an hour to an hour and a half three times a day.
For our own part, we consider the shoe to be almost if not quite superfluous, so far as its influence upon the progress of the disease is concerned. We therefore dispense with it, and have the animal exercised in his ordinary shoes. To do this, the patient has sometimes to be severely flogged into taking the first few steps. After that progress gradually becomes easier.
It has been said to be cruel. In so far as we knowingly, and of set purpose, occasion the animal pain, cruel it undoubtedly is; but it is cruelty with an aim that is truly benevolent, and the object of our benevolence is the animal upon whom the cruelty is practised.
One word of advice is needed. The forced exercise must be commenced early. In the later stages, when the stage of congestion has passed from that to the acuter stages of the inflammation and the outpouring of the inflammatory exudate, then forced exercise cannot be safely commenced. The loss of adhesion between the pedal bone and the horny box, which we know to be then existent, negatives its advisability.
By many it is advised to always remove the shoes. From what we have already said, it will be seen that this is not our practice. But one argument in favour of so doing appears to us to carry weight, and that is that ‘dropping’ of the sole is probably prevented from becoming so marked. That condition, however, is entirely dependent upon the changes occurring within the horny box. It is bound to occur with the animal shod or unshod, and to reach a stage when only contact with the ground prevents its further descent. The complication then sometimes following–namely, penetration of the sole by the bone, is not prevented by having the shoes removed. It may, in fact, be thus rendered more likely.
Internal treatment consists in the exhibition of suitable febrifuges and the administration of a dose of aloes.
With regard to the wisdom of the latter proceeding, opinion seems to be divided. Personally, we hold an open mind concerning it. This much is certain: in many cases of laminitis–those cases which have their origin in overfeeding with an irritating food–there is already a strong predisposition to enteritis. The administration of aloes in this case is extremely apt to induce a fatal super-purgation. Aloes is, again, contra-indicated when the laminitis is a result of excessively long journeys, and the patient is already greatly exhausted. Neither can it be advocated in the laminitis occurring as a sequel to septic metritis or to pneumonia.
On the other hand, when the disease has occurred as a result of long standing in the stable and an overloaded condition of the bowels, or where one full meal of some constipating food, such as whole wheat, pea or bean meal, wheat or barley meal, has occasioned the attack, then a dose of aloes at the commencement of the treatment is productive of good.
Suitable febrifuges are found in potassium nitrate, potassium chlorate, sodium sulphate, or magnesium sulphate, either of which or a mixture of two or more of them, the animal will readily take in his drinking-water.
The administration of sedatives is also indicated. In this connection aconite will be found most useful. More especially in the early stages of the disease, when pain is excessive and the temperature high, will its good effects be noticed. This also the animal will often take in his drinking-water. We have been in the habit of so prescribing the B.P. tincture in 1/2-dram doses three times daily. By its use the temperature is rapidly lowered, the pulse reduced in number and in fulness, and the pain in some instances perceptibly diminished. With others hypodermic injections of morphia and atropine have given equally satisfactory results.
Needless to say, good nursing is a _sine qua non_. During the first stages of the fever a light and easily digested diet should be allowed–bran-mashes, roots and grass when obtainable, and a carefully regulated supply of water. The animal should be warmly clothed and the box well ventilated, even to the opening of the doors and windows. Only in this way is pneumonia as a sequel sometimes prevented. The patient’s comfort should be attended to in providing him with a suitable bed. Anything in the shape of long litter should be avoided. When nothing else is at hand, litter that has already been broken and shortened by previous use is best. With this the box floor should be thickly covered, and matting of the material prevented by constant turning. A good bed for the horse with laminitis is peat-moss mixed with short straw. This, without being dragged into irregular heaps, remains springy and elastic with but little attention. Better than all, however, especially with good weather, is an open crewyard. Here the animal has an abundance of fresh air, has a bed that is always soft, and has plenty of room in which to get up and down with some degree of ease.
Leaving the dietetic and medicinal, we may consider other treatments of laminitis that come more particularly under the heading of operative.
The first matter that here demands our attention is that of allowing the exudate to escape at the sole. If after the expiration of three or four days pain and other symptoms of distress continue, then it may be judged that the inflammatory exudate has made its appearance. Operative measures allowing of its escape, though not giving absolute ease, do undoubtedly relieve the more marked expressions of suffering, and should be at once determined on. To do this completely it is necessary to cast the animal. The sole is then thinned at the toe with the drawing-knife until the sensitive structures are reached. A flow of yellow and sometimes blood-stained discharge is immediately obtained, and the sole itself found to be underrun to a considerable extent. An opening sufficiently large to admit of free drainage (about the size of a half a crown-piece) is made, the wounds antiseptically dressed, and the hobbles removed.
If showing an inclination to do so, the animal should then be allowed to remain and rest. In one instance in which we so operated (a case of laminitis in the hind-feet alone), the relief given was at once manifested. For three days previously the animal had remained standing in agonizing pain. On the fourth he was cast, and the discharge–partly inflammatory exudate, and partly a sanious foetid pus–liberated. The hobbles were removed, and the animal allowed to remain down while our attention was drawn to another case. This attended to, we walked back to the field where, our first patient was lying. His breathing, but a short time before distressedly short and catching, was now so slow and deeply regular that for one brief moment the thought flashed across our mind that he was dead. He was in a _profound_ sleep.
Other operators sometimes give the exudate escape while making the grooves in what is now known as ‘Smith’s Operation.’
In this operation the hoof is so grooved as to allow of its expansion, so relieving the pressure on the sensitive structures within it. Incidentally, the inflammatory exudate is given exit.
[Illustration: FIG. 120.–DIAGRAM OF HOOF SHOWING THE POSITION OF THE THREE GROOVES MADE IN THE TREATMENT OF LAMINITIS.]
The animal is cast, the shoes removed, and three vertical grooves made in the wall. The first is cut down the centre of toe, extending from the coronet to the ground surface. The second is made to the right of this, and the third to the left, each following the direction of the horn fibres, and each distant about 2 inches from the first (see 1, 2, and 3, Fig. 120).
Each of the grooves must run completely from the coronary margin to the ground surface, and each should be carried through the substance of the horn until the horny laminae are reached. This done, the underneath surface of the foot is grooved at the white line (see curved groove 4, Fig. 121) in such a manner as to entirely isolate the two pieces of horn _a_ and _b_ from the remainder of the hoof.
Expansion of the horny box is thus brought about, while at the same time the semicircular groove at the toe is made deep enough to allow of the escape of the exudate.
If thought wise by the operator, the two pieces of horn _a_ and _b_ may be isolated, and the exudate given exit by making the fourth groove in the position of the dotted lines in Fig. 120–that is to say, at the lowermost portion of the sensitive structures. By this means the sole will be left intact.
[Illustration: FIG. 121.–LOWER SURFACE OF FOOT SHOWING POSITION OF THE GROOVES MADE IN THE TREATMENT OF LAMINITIS.]
Fuller instruction for making the grooves and the instruments required will be found described in Section C of Chapter X.
The animal should be afterwards shod, and the bearing on the portions _a_ and _b_ of the wall removed. Almost immediate relief is afforded the patient.
_Recorded Cases_.–1. ‘On the evening of September 28 last, I was called rather hurriedly to attend a posting-horse which had just arrived from a twenty-one miles’ journey, and was said to be “very ill.” I lost no time in proceeding to the spot, and found my patient “very ill” indeed. No need for long consideration as to diagnosis; the symptoms showed at once that I had an uncommonly severe case of acute founder before me. On examination I found the pulse was 120, the respirations 100, and the thermometer 106 deg. F. The poor brute could not move, the fore-legs were well out before, and the hind-legs thrown back behind; in fact, he was, as one might say, propping himself up with his four legs!
‘On examining his feet, I discovered what I had never either seen or heard of before–namely, _blood freely oozing out_ at the coronet of all four feet; if anything, the hind-feet were the worst, and, showing that this bloody discharge at coronets had commenced during progression and before he was stabled, the inside of the thighs were all shotted over with blood, which had been thrown up by his feet while he was trotting or walking. He was completely soaked all over with perspiration.
‘My prognosis could not well be otherwise than unsatisfactory. I resolved, however, to do all I could to relieve the poor suffering brute. As a matter of course, jugular phlebotomy was utterly impracticable; so, to relieve the pressure in the feet, I had him (after, with extreme difficulty, removing the shoes) bled, or rather opened, at all four toes, and hot poultices applied. On opening the off-side toe, in both hind and fore feet, I found an escape of very dark-coloured blood, with a great many bubbles of gas, thus showing that the destructive process was fairly established in the two bony extremities mentioned. The near fore and near hind feet showed no signs of gas-bubbles on being opened at the toe.
‘I gave a laxative in combination with a diffusible stimulant, and ordered doses of aconite and potassium iodide; I also applied strong sinapisms to each side, immediately behind the shoulders. After three hours I found my patient rather easier; respiration about 90, and temperature 104 deg.; willing to take a little water, and even attempted to take some hay. Ordered continued applications of hot water to the poultices at feet, and clothed him up for the night. Next morning there was little improvement; respirations over 80, and temperature 103.5 deg.. Continue same treatment. Second morning, horse apparently easier; temperature 102.5 deg., but very difficult respiration; laxative had operated during the night; ordered diffusible stimulants. About two hours and a half after my last visit, the horse turned round in his stall and dropped down dead!
‘_History of the Horse_.–He belonged to an extensive horse-hiring establishment; was purchased a short time before for L60–a long price for a post-horse–had recently suffered and been off work from some “severe cold”; was taken out, and did forty-seven miles of a journey the day _before_ I saw him; on forenoon of the day on which he was attacked he did two or three short turns, and then twenty-one miles of a journey in the afternoon, during which he became so ill as scarcely to be able to conclude the twenty-one miles; this was the last turn he was to do. He was a grand stepper, and no doubt was pushed a little during this final journey, as the driver intended, after a short rest, to finish off with the twenty-six miles between this and home. With the short turns on the second forenoon, this would have been over 100 miles in less than two days, with a horse just out of a _severe cold_.'[A]
[Footnote A: _Veterinary Journal_, vol. xvii., p. 314 (A.E. Macgillivray).]
2. ‘Whilst attending a patient on a farm on September 5 last my attention was called to a cart-horse, five years of age, that had been castrated in the standing position by a travelling castrator about ten days previously.
‘I found the animal presenting the following symptoms: Head down, blowing hard, very dull, and disinclined to move, temperature 105 deg. F., hard, rapid, slightly irregular pulse, membranes injected, appetite lost; scrotum, sheath, and penis tremendously swollen, castration wounds unhealthy, and exuding a thin, reddish-brown discharge of a most foetid odour.
‘The next day well-marked symptoms of laminitis were present. I finally ceased attending him about the middle of October, and at the end of that month he was turned out for the winter.'[A]
[Footnote A: _Veterinary Record_, vol. xiv., p. 649 (Charles A. Powell).]
3. ‘On July 8 an interesting case of laminitis came under my notice. The subject was a mare, eight years old, which had been running on the common here for some months, and was taken up on the night of July 2 by a boy, who did not observe anything amiss with her. The following morning, on the owner going to the stable, he found the animal in great pain, and at once sent for me. I discovered her to be suffering from laminitis, and saw her again in the evening, when she was much worse. The attack proved to be a most severe one.
‘The owner informed me that she had not been allowed any corn for two months, and that she had no distance to travel on the road from the common.
‘Though on such a poor pasture, the mare was very fat; she had never been unwell before this attack.
‘This is the first case I have seen of laminitis occurring when the animal was on grass.'[A]
[Footnote A: _Veterinary Journal_, vol. ix., p. 176 (W. Stanley Carless).]
B. CHRONIC.
1. CHRONIC LAMINITIS.
_Definition_.–A low and persisting type of inflammation of the sensitive structures of the foot, characterized by changes in the form of the hoof, and incurable pathological alterations within it.
_Causes_.–Chronic laminitis more often than not is a sequel to the acute form we have just described. With an attack of acute laminitis that defies treatment, and does not end in resolution in from ten days to a fortnight, then the chronic form may be expected.
The brittle horn, convex sole, and other changes we have described under Pumiced Foot may, however, be regarded as a chronic laminitis, and this condition, as we have already indicated in Chapter VI., may run a course slow and insidious from the onset.
_Symptoms_.–When the disease arises without previous acute symptoms, the first thing noticeable is an alteration in the gait. The animal begins to go feelingly, especially when first moved out from the stable. Our opinion is asked as to the cause of the lameness, and an inspection is made. With the changes in the form of the hoof as yet wanting, we have nothing to guide us, and other causes for the lameness suggest themselves, probably corns. Evidence of these is not forthcoming, and we in all probability withhold our opinion until a later visit. On the second or a subsequent call we are perhaps lucky enough to find our patient down. Diagnosis is then rendered easier. Made to rise, the animal stands in the attitude we have described as indicative of laminitis. We have him walked and trotted out. The symptoms of tenderness disappear, and the animal soon goes fairly sound. He is, in fact, workable–that is, by anyone who is careless as to the comfort of his beast.
When following an acute attack, we have the most marked symptoms of pain and distress, somewhat abating after the second or third week. The walk, however, is still painful, and, for a short time after rising from the ground, even difficult.
In short, in both cases we have the horse going on his heels, with a walk that is painful, and with symptoms of pain that are most apparent when moved on after a rest.
Later, the changes in the form of the hoof begin to appear. It seems to have lost its elasticity, and is seen to be dry and chippy, and to have become denuded of its varnish-like outer covering.
In addition, it is of largely altered shape. The toe, by reason of the animal walking on his heels, and by reason of an increased growth of horn, becomes elevated, so that the front of the wall, instead of forming an obtuse angle with the ground, comes to run very nearly horizontal with it. The horn of the heels, as compared with that of the toe, takes on an increased growth. The same thing we have already indicated as happening at the toe, though in lesser degree. Taken together, this increased growth of horn at the toe and at the heels has the result of lengthening the diameter of the foot from before backwards, the transverse diameter remaining more or less normal. The hoof thus loses its circular build, and comes to approach nearer an elongated oval.
[FIG. 122.–FOOT BADLY DEFORMED AS A RESULT OF CHRONIC LAMINITIS.]
At this stage, too, the pathological ‘ribbing’ of the hoof is observable. The outer surface of the wall becomes marked with a series of ridges encircling the hoof from heel to heel (see Fig. 81, which illustrates a moderate deformity of the hoof occurring after laminitis). In the badly laminitic hoof, however, this deformity is largely increased, until in some cases the shapeless mass can hardly be likened to a foot at all (see Fig. 122).
The inferior or solar surface of the foot also offers certain changes for our consideration. The first thing that strikes one is the convexity of the sole. This, as we have already pointed out, is due to descent of the os pedis, and the highest point of the convex portion is that immediately in front of the apex of the frog. Here the horn is sometimes found to be quite yielding to the finger, is excessively thin, and is more or less granular and inclined to break up under manipulation. As a consequence, any rough use of the drawing-knife, or an accidental wounding with sharp flints or stones, leads to exposure of the sensitive structures and local gangrene.
With the horn of the sole thus deteriorated by reason of excessive and continued pressure upon the parts secreting it, it is not surprising to find that, in many cases, actual penetration of it with the os pedis occurs. It is the anterior portion of the inferior margin of the bone that makes its appearance, and shows itself as a small semicircular white or dark gray line on the sole.
[Illustration: FIG. 123.–SOLAR ASPECT OF FOOT WITH CHRONIC LAMINITIS, SHOWING ITS ABNORMAL OVAL SHAPE FROM BEFORE BACKWARDS, AND THE EXCESS OF HORN GROWING FROM THE WHITE LINE IN THE REGION OF THE TOE.]
Exposure of the bone is soon followed by its necrosis, in which case the wound takes on an ulcerating character. From it there is a discharge of pus, black in colour and offensive in smell, and, protruding from the opening, are excessive granulations of the remains of the sensitive sole.
The ‘white line,’ so apparent when a normal foot is cleaned with the knife, can no longer be sharply distinguished from the surrounding horn, while in some cases the horn composing it takes on an abnormal growth at the toe (see Fig. 123). This adds still further to the abnormal lengthening of the antero-posterior diameter of the foot already mentioned.
In other cases horn in this position is altogether wanting, and in its place is a well-defined cavity, into which the blade of a knife can be readily passed. This cavity is bounded in front by the original wall of the hoof, and is here lined by a degenerated and hypertrophied growth of the horny laminae. Posteriorly the cavity is bounded by the front of the os pedis, and is lined by a thin growth of horn secreted by the keratogenous membrane covering the bone. Superiorly the cavity is quite narrow, and extends to near the lower surface of the coronary cushion, while inferiorly, at its open portion, it is often 1/2 inch to 1 inch wide. Laterally it extends on each side of the toe to the commencement of the quarters.
[Illustration: FIG. 124.–LONGITUDINAL SECTION OF A FOOT WITH LAMINITIS OF THREE WEEKS’ STANDING. On the anterior face of the cavity, in front of the os pedis, are thickened horny laminae. Due to the sinking of the bony column, the os pedis has perforated the horny sole.]
Exploration with a director, or with the blade of a scalpel, removes from the opening a dry detritus. This is composed of the solid constituents of the escaped blood, the dried remains of the inflammatory exudate, and broken-down fragments of cheesy-looking horn. The size to which the cavity may sometimes extend is illustrated in Fig. 124. The thickened horny laminae forming the anterior boundary of the cavity are here depicted, together with commencing perforation of the horny sole by the os pedis. It is this cavity which, when opened at the bottom and discharging its mealy-looking contents, is known as seedy-toe, for a further description of which see p. 293.
The lameness occurring with chronic laminitis does not always persist. As time goes on the sensitive structures accommodate themselves to the altered form and conditions of the horny box. In certain situations–namely, where pressure is greatest–the softer structures become atrophied, and sometimes even wholly destroyed; while in other positions the changes in form of the hoof tend to increase in size of its interior, with a consequent diminution of pressure upon, and increased growth of the structures within it.
_Pathological Anatomy_.–In detailing the changes to be observed in chronic laminitis, we take up the description where we left it when dealing with the pathological anatomy of the acute form. The alterations to be met with are best observed by taking a foot so diseased and making of it two sections–one longitudinal, from before backwards; the other horizontal, and in such a position as to cut the os pedis through at its centre.
These sections will expose to view the cavity formed by the pouring out of the exudate, and its full extent may be noticed by examining the sections alternately. Taking the horizontal section first, it will be seen that the hollow space extends wholly round the toe, and as far back as the commencement of the quarters. In the latter position one is able to observe laminae still in their normal positions and condition. At the toe, however, the horny and secretive laminae are widely separated, and the space between them filled with a yellow, semi-solid material, the remains of the inflammatory exudate and new horn secreted by the keratogenous membrane. The laminae, both horny and sensitive, are greatly enlarged. This is a hypertrophy, resulting from the continued effects of the inflammation, and leads in time to the formation of laminae quite three or four times their normal size. It is this hypertrophy of the laminae and the pressure of the exudate that causes the bulging and increased growth of the horn at the toe (see Fig. 125), and contributes towards the oval formation of the foot we have mentioned before.
[Illustration: FIG. 125.–LONGITUDINAL SECTION OF A FOOT WITH LAMINITIS OF SEVERAL YEARS’ DURATION.]
In the longitudinal section the first thing noticeable is the change in position of the bones, more especially in that of the os pedis. The circumstances we have mentioned before–pressure of the exudate upon it in front and tension of the perforans on it behind–have caused it to assume a more upright position than is normal, so much so that in a bad case the front of the bone becomes quite vertical. This vicious direction the other bones of the digit follow (see Fig. 125).
Consequent upon the displacement of the bone, the plantar cushion, by reason of the continued pressure thus put upon it, becomes atrophied, while its hinder half is, as it were, squeezed into taking up a position more posterior and higher in the digit than normally it should. The horn-secreting papillae covering its inferior face thus become directed backwards sooner than downwards, in which way we account in some measure for the noticeable increase of horn at the heels.
_Treatment_.–Chronic laminitis is incurable. Treatment must therefore be directed towards the palliation of such conditions as are present, with the object of rendering the the animal better able to perform work. When perforation of the sole has occurred, with the attendant formation of pus and necrosis of the os pedis, it is doubtful whether treatment of any kind is advisable. There are on record cases of this description, where careful curetting of the exposed and necrotic portions and the after application of antiseptic dressings, held in position by a plate shoe or a leather sole, has been followed by good results, and the animal restored for a time to labour. In our opinion, however, early slaughter is the most economical course to adopt, and certainly the wisest advice to give to the ordinary client.
When perforation of the sole is absent, and when serious alteration in the shape of the horny box has not occurred, then the most simple treatment is to put the animal straight away to slow work, with the feet protected by suitable shoes.
Here, again, the most useful shoe is the Rocker Bar (Fig. 119). The broad web and deep seating gives ample protection to the convex sole, and with the ease in distributing his weight that this shoe affords the animal is able to perform slow work on soft lands with some degree of comfort.
Should the growth of the horn at the toe and at the heels be unduly excessive, then our attention may be directed towards reducing it to some approach to the normal. This is accomplished by removing with the rasp and the knife those portions indicated by the dotted lines in Fig. 127. Here it will be seen that the bulk of the horn removed is that protruding at the toe. After this the animal should again be suitably shod. In this connection it should be noted that the fact of the animal walking largely on the heels tends to a forward displacement of the shoe. This must be prevented by providing each heel of the shoe with a clip, after the manner shown in Fig. 128; or, in the case of a bar shoe, supplying it with a clip at the centre of the bar.
[Illustration: FIG. 126.–DIAGRAM ILLUSTRATING THE ABNORMAL GROWTH OF HORN AT THE TOE AND HEELS OF THE FOOT WITH CHRONIC LAMINITIS.]
[Illustration: FIG. 127.–THE SAME FOOT AS IN FIG. 126. The dotted lines show the excess of horn removed preparatory to shoeing.]
Among other treatments to be noted we may mention one or two to be found chiefly in Continental works on this subject.
The method of Gross consists in thinning down with a rasp about 1-1/2 inches of the horn of the wall immediately below the coronet, the thinned portion extending from heel to heel. The groove made is filled with basilicon ointment,[A] and the coronet stimulated with a cantharides ointment, In this way there is induced to grow from the coronet a new wall of nearly normal dimensions.
[Footnote A: Basilicon ointment is made by heating together resin 8 parts, beeswax 8 parts, olive oil 8 parts, and lard 6 parts. Allow to cool without stirring.]
By other operators (Bayer, Imminger, Meyer, and Gunther) this treatment has been modified by enlarging upon it and removing the whole of the adventitious horn.
[Illustration: FIG. 128.–THE SHOE WITH HEEL-CLIP.]
This is done by means of the drawing-knife and the rasp, the ugly-looking pumiced foot being carefully cut and trimmed until, so far as outward appearances are concerned, it is perfectly normal. This done, the whole foot is treated with a suitable hoof ointment, and a shoe applied that affords protection to the sole without imposing pressure upon it. The shoe indicated is either an ordinary shoe with an unusually broad and well-seated web, or the seated Rocker Bar of Broad. With either it is well to additionally protect the sole by means of a leather or rubber pad and tar stopping, or by using the Huflederkitt described on p. 148. In every case the nails must be kept well back in order to avoid the weakened and degenerated horn at the toe, and to take advantage of the greater growth of horn at the heels.
The wisdom of thus removing the whole of the adventitious horn may be questioned. Although a foot of a nearly normal shape is obtained, it must be remembered that the grave alterations within it are unchanged, and that in certain positions the operation must have carried us nearer the sensitive structures than is advisable.
All other treatments failing, the operation of neurectomy has been advised. This we do not think wise. One would imagine that, with degenerative processes already going on in the foot, the tendency to gelatinous degeneration, always to be looked for in neurectomy, would be increased. This, as a matter of fact, is the case, and is borne out by the statements of those who have tried this method of treatment. In many cases the lameness even is not got rid of. Even where it is, the operation is afterwards followed by a great tendency to stumble, by sloughing of the hoof, or by a marked increase in the adventitious horn, and a consequent greater deformity of the foot.
Sooner than risk neurectomy, it seems to us wiser to give a trial to the operation advocated by M.G. Joly, namely, that of ligaturing one of the digital arteries on each affected foot. This operation is performed in the same position as is the higher operation of plantar neurectomy, and may be either internal or external. The vessel is exposed, and a double ligature, preferably of silk, placed on it. The artery is then divided between the two ligatures. The immediate effect of the operation is to cause a considerable diminution in the arterial pressure, and so lessen the intensity of the ostitis in the os pedis. Its consequences are not so serious as those of neurectomy, and it decongests tissues which neurectomy congests.
In cases related by M. Joly this operation, practised both in conjunction with removal of the excess of horn and without it, has resulted in a marked improvement in the gait, the animal going to work one month after the treatment, and remaining sound for some time afterwards.
2. SEEDY-TOE.
_Definition_.–A defect in the horn of the wall, usually at the toe, but occurring elsewhere, resulting in loss of its substance in either its internal or external layers (see Figs. 129, 130, and 131).
_Causes_.–The most common factor in the causation of this defect is undoubtedly disease of the sensitive laminae. We have, in fact, just given an excellent example of the formation of a seedy-toe in the sections of this chapter devoted to laminitis (see pp. 265 and 286). The cavity here formed by the outpouring of the inflammatory exudate and the separation of the sensitive and horny laminae persists. It becomes filled with the dried remains of the exudate and perverted secretions from the horny and sensitive laminae (see p. 287). As yet, however, the cavity is closed below, and its existence only surmised. Later, with successive visits to the forge, the layer of solar horn forming its floor is cut away, and the cavity exposed to view. Its mealy-looking contents are removed, and the case reported by the smith.
Although occurring in this way with an acute attack of laminitis, it must be remembered that seedy-toe may arise without previous noticeable cause. The first intimation the owner has is a report from the forge that seedy-toe is in existence. To refer to cases so arising a probable cause is far from easy. At one time it was believed to be due to parasitic infection of the horn. Others have blamed the pressure of the toe-clip, excessive hammering of the wall, or pressure from nails too large or driven too close. Others, again, say that seedy-toe may result from a prick in the forge, from hot-fitting of the shoe, from standing on a dry and sandy soil, or from the use of high calkins on the front shoes. In these cases–cases with an insidious onset–we are inclined to the opinion that the disease of the horn commences from below, and that the sensitive laminae become implicated later. Holding this view, one must account for the commencing disease of the horn by giving, as causes, firstly, those factors (as, for instance, alternate excessive dampness and dryness) leading to disintegration of the horn tubules; secondly, the penetrating into and between the degenerated tubules of parasitic matter from the ground; and, thirdly, the final breaking up of the horn, and spread of the lesion under the invasion thus started.
[Illustration: FIG. 129.–DIAGRAM ILLUSTRATING POSITION OF SEEDY-TOE (INTERNAL). 1, The horn of the wall; 2, the horn of the sole; 3, the cavity of the seedy-toe; 4, the os pedis; 5, the keratogenous membrane.]
_Symptoms_.–Lameness sometimes attends seedy-toe, and sometimes does not. This is an important point to be carried in mind by the veterinary surgeon who is accustomed in his practice to have many animals pass through his hands for examination as to soundness. An animal with advanced seedy-toe–a condition constituting serious unsoundness–may walk and trot absolutely sound, and may give no indication, either in the shape of the wall or the condition of the sole, that anything abnormal is in existence. Later, however, after the veterinary surgeon has passed him, the purchaser lodges the complaint that the horse has a bad seedy-toe, which, so he is told, must have been there for some time. In this case, culpable though he may appear, there is every excuse for the veterinary surgeon.
Once the cavity is opened at the toe in the neighbourhood of the white line, then diagnosis is easy. A blunt piece of wood, the farrier’s knife, or a director may be easily passed into it, sometimes as far up as the coronary cushion (see Fig. 129). Issuing from the opening is seen occasionally a little inspissated pus; more often, however, the dry, mealy-looking detritus to which we have before referred. This form of the disease we may term ‘Internal Seedy-Toe.’ for, plainly enough, it has had its origin in chronic inflammatory changes in the keratogenous membrane.
[Illustration: FIG. 130.–EXTERNAL SEEDY-TOE COMMENCING AT THE PLANTAR BORDER OF THE WALL.]
[Illustration: FIG. 131.–EXTERNAL SEEDY-TOE COMMENCING ON THE ANTERIOR FACE OF THE WALL.]
Disease of the horn and loss of its substance may, however, also commence from without. A report on this condition, under the title of ‘External Seedy-Toe,’ is to be found in vol. xxix. of the _Veterinary Journal_, from which we borrow Figs. 130 and 131.
In Fig. 130 it will be seen that the disease commences at the plantar surface of the toe, and extends upwards and inwards. The same condition may also appear anywhere between the coronet and the ground, gradually extending into the substance of the wall, as shown in Fig. 131. According to the writer, Colonel Nunn, the progress of the disease in this latter case appears to be faster in a downward than in an upward direction. This, however, is more apparent than real, as the rate of growth of the horn downwards detracts from the progress of the disease upwards, although it spreads over the horn at the same rate.
Before concluding the symptoms, we may again allude to the fact that, although usually occurring at the toe, the same condition may be met with in other positions–namely, at either of the quarters. In appearance and in other respects it is identical with that occurring at the toe.
When the animal is lame and the existence of seedy-toe is surmised, or when the cause of the lameness is altogether obscure, a little information may perhaps be gathered from noting the wear of the shoe. If the animal has been going lame for any length of time as a result of disease in the sensitive laminae, then the shoe will be greatly thinned at the heels, and the toe but little worn.
_Treatment_.–As with diseased structures elsewhere, the most rational treatment, when possible, is that of excision. The entire portion of the wall forming the anterior boundary of the cavity is thinned down with the rasp and afterwards removed with the knife, wholly exposing the hypertrophied, but usually soft layer of horn covering the sensitive structures. These hypertrophied portions are also removed, and every particle of the dust-like detritus cleaned away. After-treatment consists in dressing the parts with a good hoof ointment, protecting them, if necessary, with a pad of tow and a stout bandage. It may be that the removal of a large portion of the wall may for some time throw the animal out of work. Acting on Colonel Fred Smith’s suggestion, this may be avoided by having made a thin plate of sheet-iron, slightly larger in circumference than the portion of horn removed, and shaped to follow the contour of the foot. This made, it is sunk flush with the wall by hot-fitting it, and kept in position by several small steel screws fixed into the sound horn, just as in the treatment for sand-crack (see p. 174). This will serve the useful purpose of maintaining in position any dressing that may be thought necessary, of acting as a support to the horn left on each side of the portion removed, and of keeping the exposed structures free from dirt and grit.
Practical points to be remembered in fitting plates of this description to the feet are: The plate must never quite reach the shoe, or it will participate in the concussion of progression, and so loosen the screws that hold it in place. For the same reason, that portion of the sole adjoining the piece of horn removed must have its bearing on the shoe relieved. The screws holding the plate should be oiled to prevent rusting, and should take an oblique direction in order to obtain as great a hold as possible on the wall.
When excision is deemed unwise or unnecessary, treatment should be directed towards maintaining the cavity in a state of asepsis. To this end it should be thoroughly cleaned of its contents, and afterwards dressed with medicated tow. The ordinary tar and grease stopping is as suitable as any. This, together with the tow, is tightly plugged into the opening and kept in position by a wide-webbed shoe. Instead of the tar stopping and the tow, there may be used with advantage the artificial hoof-horn of Defay (see p. 152). Before using this the cavity should again be thoroughly cleaned out, and should in addition be mopped out with ether. The latter injunction is important, as unless the grease is thus first removed, the composition will fail to adhere to the horn. With the cavity thus cleaned and prepared, the artificial horn, melted ready to hand, is poured into it and allowed to set.
In every case, no matter what else the treatment, the bearing of the horn adjacent to the lesion should be removed from the shoe.
Whether practising the method of plugging the cavity or that of excision of the wall external to it, attempts to quickly obtain a new growth of horn from the coronet should be made. To further that, frequent stimulant applications should be used. Ointment of Biniodide of Mercury 1 in 8, of Cantharides 1 in 8, or the ordinary Oil of Cantharides, either will serve.
3. KERAPHYLLOCELE.
_Definition_.–By this term is indicated an enlargement forming on the inner surface of the wall. In shape and extent these enlargements vary. Usually they are rounded and extend from the coronary cushion to the sole, sometimes only as thick as an ordinary goose-quill, at other times reaching the size of one’s finger. Often they are irregular in formation and flattened from side to side.
[Illustration: FIG. 132.–A PORTION OF THE HORN OF THE WALL AT THE TOE REMOVED IN ORDER TO SHOW A KERAPHYLLOCELE ON ITS INNER SURFACE.]
_Causes_.–Keraphyllocele is very often a sequel to the changes occurring at the toe in laminitis. Probably, however, the most common cause is an injury upon, or a crack through, the wall. It may thus occur from excessive hammering of the foot, from violent kicking against a wall or the stable fittings, and from the injury to the coronet known as ‘tread.’ It may also occur as a sequel to complicated sand-crack, and to chronic corn.
That fissures in the wall are undoubtedly a cause has been placed on record by the late Professor Walley, who noticed the appearance of these horny growths following upon the operation of grooving the wall.[A]
[Footnote A: _Journal of Comparative Pathology and Therapeutics_, vol. iii, p. 170.]
This gentleman had a large Clydesdale horse under his care for a bad sand-crack in front of the near hind-foot, and, as the lameness was extreme, he adopted his usual method of treatment–viz., rest, fomentations, poulticing, and the making of the V-shaped section through the wall, and subsequently the application of an appropriate bar shoe to the foot, and repeated blisters to the coronet. In a short time the lameness passed off, and the horse was put to work. A few days later the animal met with an accident, and was killed.
On examining a section of the hoof it was found that a vertical horny ridge corresponding to the external fissure had been formed on the internal surface of the wall, and that a well-marked cicatrix extended upwards through the structure of the hoof at the part forming the cutigeral groove; furthermore, _a similar ingrowth had been taking place in the line of the oblique incisions made for the relief of the sand-crack_.
This case has an important bearing on the operation of grooving the wall, which operation we have several times in this work advocated for the relief of other diseases. It teaches us that the incisions should not be carried so completely through the horn as to interfere with and irritate the sensitive laminae, and so set up the chronic inflammatory condition leading to hypertrophy of the horn.
From the position on the os pedis of the indentation made in it by the keraphyllocele (see Fig. 133) it has been argued that pressure of the toe-clip is a cause of the new growth. This, we should say, cannot be a very strong factor in the causation, for, while we admit that the continual pressure of the clip, and the heavy hammering that sometimes fits it into position, is likely to set up a chronic inflammatory condition of the sensitive laminae in that region, we must still point out that the rarity of keraphyllocele, as compared with the fact that clips are on every shoe, does not allow of the argument carrying any great weight.
_Symptoms_.–Except under certain conditions this defect is difficult of detection. As a rule, lameness is not produced by it. In making that statement we are led largely by the conclusion arrived at by Professor Walley. This observer noted the fact that ingrowths of horn such as we are describing nearly always take place in false quarter, or after a sand-crack has been repaired, and that they commonly occur after the operation of grooving the wall in the manner we have just shown.
Now, we know that quite often under these circumstances the horse goes perfectly sound. Thus, while we know that in all probability keraphyllocele is in existence, we have ocular demonstration that the animal is quite unaffected by it.
In some cases, however, lameness is present. During the early stages of the growth’s formation it is but slight, increasing as the keraphyllocele enlarges. Should this be the case, other symptoms present themselves. The coronet is hot, and tender to the touch, sometimes even perceptibly swollen, and percussion over the wail is met with flinching on the part of the animal. In other cases one is led to suspect the condition by the prominence of the horn of the wall of the toe. This is distinctly ridge-like from the coronet to the ground, while on either side of it the quarters appear to have sunk to less than their normal dimensions. We believe this to be an illusion, as a ridge of any size at the toe readily gives one the impression of atrophy behind it, without this latter condition being actually present.
Should this ridge-like formation and the accompanying symptoms of pain and lameness occur after repair of a sand-crack, then keraphyllocele may, with tolerable certainty, be diagnosed. When these outward signs are wanting, however, and the true nature of our case is a matter of mere conjecture, a positive diagnosis may still be made at a later stage–that is, when the abnormal growth of horn reaches the sole. In this case either there is met with when paring the sole a small portion of horn, circular in form, distinctly harder than normal, and indenting in a semicircular fashion the front of the white line at the toe, or solution of continuity between the tumour and the edge of the sole and the os pedis takes place, and the lameness resulting from the ingress of dirt and grit thus allowed draws attention to the case.
_Pathological Anatomy_.–With the sensitive structures removed from the hoof by maceration or other means, these growths are at once apparent. They may occur in any position, but are usually seen at the toe, and they may extend from the coronary cushion to the sole, or they may occupy only the lower or the upper half of the wall. In places the tumour (or ‘horny pillar’ as the Germans term it) is roughened by offshoots from it, and does not always exhibit the smooth surface depicted in Fig. 132. Commonly, the horn composing the new growth is hard and dense. Sometimes, however, it is soft to the knife, and is then found to be itself fistulous in character, a distinct cavity running up its centre, from which issues a black and offensive pus.
In a few cases the sensitive laminae in the immediate neighbourhood are found to be enlarged, but in the majority of cases atrophy is the condition to be observed. Not only are the sensitive structures found to be shrunken and absorbed, but the atrophy and absorption extends even to the bone itself (see Fig. 133). This latter is a result of the continued pressure of the horny growth, in a well-marked case ending in a sharply-defined groove in the os pedis in which the keraphyllocele rests. The fact that the softer structures, and even the bone, thus accommodate themselves to the altered conditions is, no doubt, the reason that lameness in many of these cases is absent.
_Treatment_.–It is doubtful whether anything satisfactory can be recommended. When we have suspected this condition ourselves, it has been our practice to groove the hoof on either side of the toe, after the manner illustrated in Fig. 120, and, at the same time, point-firing the coronet and applying a smart cantharides blister. Certainly, after this operation, lameness has often disappeared–whether, however, as a result of the treatment adopted or by reason of the structures within accommodating themselves to the condition, we would not care to say.
[Illustration: FIG. 133.–OS PEDIS SHOWING THE GROOVE IN IT CAUSED BY ATROPHY AND ABSORPTION INDUCED BY PRESSURE OF A KERAPHYLLOCELE.]
Other writers advocate the removal of that portion of the wall to which the tumour is attached, after the manner described on p. 182, and illustrated in Fig. 98. This, however, should be a last resource, and should be adopted only when weighty reasons, such as excessive and otherwise incurable lameness, appear to demand it.
4. KERATOMA.
In our nomenclature the terms ‘Keratoma’ and ‘Keraphyllocele’ are both used to indicate the condition we have just described. There are some, however, who reserve the term ‘Keratoma’ for horny tumours occurring only on the sole, and for that reason we draw special attention to the word here. Keratoma may thus be used to describe what we have called keraphyllocele directly that growth makes its appearance at the sole, and is there able to be cut with the knife. Similar hard and condensed growths may, however, make their appearance on the sole in other positions quite removed from the white line, plainly being secreted by the villous tissue of the sensitive sole, and having no connection whatever with the sensitive laminae. They appear as circular patches, varying in size from a shilling to a two-shilling piece. Compared with the surrounding horn, they stand out white and glistening, while in structure they are dense and hard, and offer a certain amount of resistance to the knife. They are of quite minor importance, and, beyond keeping them well pared down, need no attention. Keratoma probably offers us the best analogy we have to corn of the human subject.
5. THRUSH.
_Definition_.–A disease of the frog characterized by a discharge from it of a black and offensive pus, and accompanied by more or less wasting of the organ.
_Causes_.–The primary cause of this affection is doubtless the infection of the horn, and later the sensitive structures, with matter from the ground. Those factors, therefore, leading to deterioration of the horn, and so exposing it to infection, may be considered here. Such will be changes from excessive dampness to dryness, or _vice versa_; work upon hard and stony roads; prolonged standing in the accumulated wet and filth of insanitary stables, or long standing upon a bedding which, although dry, is of unsuitable material.
In this latter connection may be mentioned the harm resulting from the use of certain varieties of moss litter. This we find pointed out by J. Roalfe Cox, F.R.C.V.S.[A] Tenderness in the foot was first noticed, and, on examination, the horn of the sole and of the frog was found to be peculiarly softened. It afforded a yielding sensation to the finger, not unlike that which is imparted by indiarubber, and on cutting the altered horn it was almost as easily sliced as cheese-rind. The outer surface being in this way slightly pared off, the deeper substance of the horn was discoloured by a pinkish stain. The horn of the frog was in many instances found detaching from the vascular surface, which was very disposed to take on a diseased action, somewhat allied to canker, and became extremely difficult to treat.
[Footnote A: _Veterinary Journal_, vol. xvi., p. 243.]
Conditions such as these, although not constituting the disease itself, certainly lay the frog open to infection, especially if afterwards the animal is called upon to work in the mud of the streets of a large town, or to stand in a badly drained and damp stable.
A further cause of thrush is to be found in the condition of the frog, brought about by contraction of the heels (see p. 118). We have already seen that one of the most prominent factors in the causation of contraction is the removal of the frog from the ground by shoeing, with its consequent diminution in size and deterioration in quality of horn. This leads to fissures in the horny covering, and favours infection of the sensitive structures beneath. Thrush is, in fact, nearly always present in the later stages of contracted foot.
By some thrush is believed to be but the commencement of canker. With this, however, we do not hold. We believe both to be due to specific causes as yet undiscovered, but that the cause of thrush is not the one operating in canker. In arriving at this conclusion we are guided by clinical evidence. The two conditions are quite dissimilar, even in appearance, and, while one is readily amenable to treatment, the other is just as obstinately resistant.
_Symptoms_.–The symptoms of thrush are always very evident. Probably the first thing that draws one’s attention to it is the stench of the puriform discharge. The foot is then picked up and the characteristic putrescent matter found to be accumulated in the median, and often in the lateral, lacunae. The organ is wasted and fissured, the horn in the depths of the lacunae softened and easily detachable, and portions of the sensitive frog often laid bare.
With a bad thrush lameness is present, the frog itself is tender to pressure, and often there is considerable heat and tenderness of the heels and the coronet immediately above. More especially is this noticeable after a journey.
It is, perhaps, more common in the hind-feet than in the fore, and more often met with in heavy draught animals than in nags. The hind-feet are, of course, more open to infection by reason of their being constantly called upon to stand in the animal discharges in the rear of stable standings, while it is a well-known fact that heavy animals have their stables kept far less clean, and their feet less assiduously cared for, than do animals of a lighter type.
In a nag-horse with thrush of both fore-feet lameness becomes sometimes very great. The gait when first moved out from the stable is feeling and suggestive of corns, while progress on a road with loose stones is sometimes positively dangerous to the driver.
_Treatment_.–When this condition has arisen, as it often does, from want of counter-pressure of the frog with the ground, this pressure must be restored after the manner described when dealing with the treatment of contracted foot (see p. 125) either by the use of tip or bar shoes, or by suitable pads and stopping.
So far as direct treatment of the lesion itself is concerned, the first step is to carefully trim away all diseased horn and freely open up the lacunae in which the discharge has accumulated. Good results are then often arrived at by poulticing, afterwards followed up by suitable antiseptic dressings. With us a favourite one is the Sol. Hydrarg. Perchlor. of Tuson, used without dilution. Others use a dry dressing, and dust with Calomel, with a mixture of Sulphate of Copper, Sulphate of Zinc and Alum, or with Subacetate of Copper and Tannin.
With restoration, so far as is possible, of the frog functions, and with careful dressing, a cure is nearly always obtained.
6. CANKER.
_Definition_.–Under this unscientific, yet expressive term, is indicated a chronic diseased condition of the keratogenous membrane, commencing always at the frog, and slowly extending to the sole and wall, characterized by a loss of normal function of the horn secreting cells, and the discharge of a serous exudate in the place of normal horn.
_Causes_.–The exact cause of canker has still to be discovered. Therefore, before expressing an opinion as to what the _probable_ cause may be, we may state here that such opinion can only be based upon clinical observation. Such being the case, we are almost duty bound to give the views of older authors before those of more modern writers.
From the mass of material ready to hand we may select the following as serving our purpose.
The earliest opinion appears to have been that canker, as the name indicates, was of a cancerous or cancroid nature. This was also believed by Hurtrel D’Arboval, who looked upon canker as carcinoma of the recticular structure of the foot. The same theory we find enunciated in the _Veterinary Journal_ so late as 1890. Although the word ‘cancer’ or ‘carcinoma’ is not there used, the author employs the terms ‘Papilloma’ and ‘Epithelioma’ with the evident intention of expressing his belief in the malignant nature of the disease.
Another early opinion was that the disease was a _spreading ulcer_, gradually extending and changing the tissues which it invaded.
A further early theory, and one which if not still believed in, has died a hard death, is the constitutional theory. This was believed in by nearly all the older writers, and is mentioned so late as 1872 by the late Professor Williams. In his ‘Principles and Practice of Veterinary Surgery,’ he says: ‘Canker is a constitutional disease due to a cachexia or habit of body, grossness of constitution, and lymphatic temperament.’ This, we believe, is credited to-day by some, and yet, quite 100 years before the date of the 1872 edition of Williams’s work–in 1756, to be exact–we find a veterinary writer when talking of grease (a disease, by-the-by, very closely allied to canker) exclaiming against this habit of referring everything which we do not rightly understand to some ill-humour of the body. The wisdom his words contain justifies us in giving them mention here. ‘It is a very foolish and absurd Notion,’ he says, ‘to imagine a Horse full of Humours when he happens to be troubled with the Grease. But such Shallow Reasoning will always abound while Peoples’ Judgments are always superficial. Therefore, to convince such unthinking Folks, let them take a thick Stick and beat a Horse soundly upon his Legs so that they bruise them in several Places, after which they will swell, I dare say, and yet be in no danger of Greasing. Now, pray, what were these offending Humours doing before the Bruises given by the Stick?’
At the present day it is safe to assert that neither the ulcerative, the cancerous, nor the constitutional theory is believed in widely, and, among the mass of contrary opinions as to the cause of this disease, we may find that even quite early many of the older writers had discarded them.
Quoting from Zundel, we may say that Dupuy in 1827 considered canker as a hypertrophy of the fibres of the hoof, admitting at the same time that these fibres were softened by an altered secretion; while Mercier in 1841 stated that canker was nothing more than a chronic inflammation of the reticular tissue of the foot, characterized by diseased secretions of this apparatus.
Saving that they make no mention of a likely specific cause, these last two statements express all that we believe to-day. As early as 1851, however, the existence of a specific cause was hinted at by Blaine in his ‘Veterinary Art.’ We find him here describing canker as a _fungoid_ excrescence, exuding a thin and offensive discharge, which _inoculates_ the soft parts within its reach, particularly the sensitive frog and sole, and destroys their connections with the horny covering.
The use of the word ‘fungoid,’ and particularly that of ‘inoculate,’ is suggestive enough, and is evidence sufficient that either Blaine or his editor recognised, simply through clinical observation, the working of a special cause.
Four years later, Bouley is found holding the opinion that canker was closely allied to tetter, thus recognising for it a local specific cause. The same observer also pointed out that the secretion of the keratogenous membrane instead of being suspended was greatly increased, taking care to explain, as did Dupuy, that the products of the secretion were perverted and had lost their normal ability to become transformed into compact horn.
In 1864 this slowly growing recognition of a specific cause received further impetus from the statements of Megnier. This observer claimed to have discovered in the cankerous secretions the existence of a vegetable parasite (namely, a cryptogam, as in favus), which he termed the keraphyton, or parasitic plant of the horn.
Modern research, though failing to substitute anything more definite, has not confirmed this. The exact and exciting cause of canker is therefore still an open question, and a matter for research. We may, however, sum the matter up by briefly discussing the causes, so far as clinical observation teaches us. This we shall do under two headings–namely, _Predisposing_ and _Exciting_.
_Predisposing Causes_.–Starting with the assumption that the disease is due to local infection, we may relate as predisposing causes anything having a prejudicial effect upon the horn, disintegrating it, and so laying the tissues beneath open to attack. The most prominent in this connection is certainly a continued dampness of the material on which the animal has to stand. Particularly is this the case when the material is also excessively foul and dirty, contaminated with the animal discharges, and presumably swarming with the lower forms of animal and plant life. We shall therefore find bad cases of canker in stables where the “sets” are irregular, or where no paving at all is attempted, where the drainage is defective, and where darkness and want of proper ventilation favours organismal growth. The fact that with modern drainage and a general hygienic improvement in stabling, canker has to a large extent died out, supports this contention.
Again, as with thrush, anything removing the counter-pressure of the frog with the ground and throwing that organ out of play, may be looked upon as a predisposing cause. The atrophy of the frog thus occurring, the deterioration in the quality of its horn and the fissures in its surface lay it specially open to infection. That one of the principal factors in the treatment of canker is a restoration of ground-pressure to the frog and the sole is sufficient proof of this.