A very expressive parallel for the inferior aspect of the plantar cushion would be a fore-shortened pair of scissors, whose handles were imperforate. The handles would correspond to the bulbs, the gap between them to the median lacuna, and the closed cutting blades to the pyramidal eminence.

Thus much, well known I have no doubt to the majority of the readers, I have gone over as a preliminary to the discussion of subjects which, as the sequel will show, are complex and controversial enough.

503 JERSEY AVENUE, Jersey City, N. J.

ART. VIII. ON THE AFFECTION COMMONLY TERMED" CORN" IN THE EQUINE FOOT.

BY JAMES HAMILL, D. V. S.,

CONSULTING SURGEON AND LECTURER ON THE ART OP SHOEING, AS APPLIED TO THE NORMAL AND PATHOLOGICAL Foot,

COLUMBIA VETERINARY COLLEGE.

MONG the numerous diseases of the horse's foot, that

A commonly denominated "CORN" is perhaps the most

troublesome, one of the most frequent, most persistent, least understood and worst treated affections that falls to the lot of the veterinary surgeon or his humble assistant, the shoeing smith. Should the student of the subject refer to veterinary literature from the earliest times to the present day, he will only find confusion worse confounded as to the etiology, pathology and treatment of Corn. The subject is generally passed over glibly in a short paragraph, glittering with generalities or paradoxes, to illustrate which I append one such extract from a deservedly well-known work; it reads as follows: "Corn is an extravasation of blood into the meshes of the horn fibre from a rupture of the

blood vessels which secrete the horn of the part, caused by external concussion or bruise, generally from improper shoeing." Now, a definition, to be a definition, should cover the whole subject to be defined; yet this definition fails to cover the case of the worst kind of corn we find; it defines only the very simplest variety. Blinding the reader to the dangers of a virulent disease, such a definition leads to an incalculable amount of damage to the horse, and on the grounds of humanity and science no effort should be spared to correct it.

To illustrate my meaning, I shall recount a typical case. A gentleman owns a valuable horse which begins to go a little lame; the animal is sent to the shoeing smith to have the foot examined; the examination reveals pain and inflammatory heat in one or both heels. The recesses formed by the inflection of the wall are pared out, and the well-known red-colored horn substance appears. "The horse has corns" is the dictum; then the stereotyped routine procedure for relieving "corn" is gone through with; the horse is a little better for a time, but it is not long before it has to be gone over again and again, only with this difference, that the relief is less and less and shorter and shorter with each repetition of the so-called curative procedure. The veterinary surgeon is now called in, gets the history of the case, and of course he must vary the treatment a little; the smith is ordered to pare out the part thoroughly, and to see if there is no pus. Probably the entire sole is thinned down, and perhaps, to please the whims of some new-fledged V. S., D. V. S., or even an M. R. C. V. S., the foot is put in either hot or cold water, rather according to the fancy of the one treating the animal than the requirements of the case; this is then followed by poulticing. If suppuration does not occur, two or three days of this treatment will generally relieve the animal. The veterinarian then orders the shoe to be eased or raised off the heel, the shoe to be tacked on, or driven very loosely; the animal walks apparently sound, and the doctor is, of course, complimented for his skill and ability. Complimented for what? For actually injuring the foot; perhaps for having inflicted almost irreparable damage!

To every observant student of the foot it must be clear that

this paring of the sole and digging down in the heel causes a permanent injury to the parts within, and that the springing of the shoe off the heel means so much friction, and friction in its turn is so much more wasting of the hoof or horn structure, and ultimately death to some other part, due to the unequal pressure which usually bears most heavily on the weakest and thinnest portion of the wall, viz., the delicate elastic quarter, the very part we should protect most, as here the fibro cartilage portions take their rise, and it is here that the natural process of transition is going on from the cartilage to the ospedis, which, if injured by any means, exhibits inflammatory reaction immediately, and, extending to the entire cartilage, provokes premature and excessive ossification, with all its accompanying evils. Then, through the same unequal pressure, which is also exerted on the plantar surface of the hoof, we get the shrunken, narrow, wasted, disproportioned, in short, generally deformed foot-a foot imperfectly fitted to support weight, and detrimental to the animal's powers of speed and endurance, not to say anything about beauty. If those interested in preventing cruelty to the horse, as Mr. Henry Bergh, for example, and the society over which he presides, only knew half the miseries the horse suffers through this pernicious system of treatment, I fancy that he would try to get a bill through the Legislature for the extermination of Horse Doctors.

Lovers of the horse are forever harping on the suffering of the "noble horse," through man's inhumanity, but' it is only the most trivial sufferings which they grapple with. But now comes the question: If this treatment is improper and injurious, what else can be done with a case of corn? I will say, better let it alone altogether, than treat it in this barbarous and unphilosophical manner. At any rate let us try first to learn what this pain in the heel, and the bloody infiltrated appearance of the horn is due to.

I admit that bad shoeing produces corns, and that any kind of shoeing will produce them; but such corns are generally of the mildest type, and can be easily eradicated. I deny, however, most decidedly, that shoeing is always a cause, and I claim that the assertions of those who say that unshod horses have no

corns is false, or only applies to those on pasture or working but very little, and that on soft roads I have seen horses that were never shod suffer from foot ailments, and among them corns occupied a prominent place. I am no radical advocate for any particular system of shoeing, and I am most ready to admit that no horse ever was, nor ever will be, properly shod with iron, and that no system of shoeing will give entire satisfaction in regard to the health of the foot, as long as circumstances compel us to use iron and steel as a protection to the hoof, as some of the natural functions of the hoof must be checked and others limited by such an unyielding appliance. But, does it follow, that because shod, all shod horses will have corns? Certainly not! Neither will all horses be free from corns! Then what is "corn"? It is not a "bruise"; it is not a rupture of blood vessels; neither is it horn rot, as some have described it. Nor is it caused by the impinging of the ospedis on the sensitive tissues lying between it and the horny sole, for in that case it would have to be looked for in different localities, at different ages of the horse. In the young foot the ospedis does not extend by its retrossal processes as far back as the situation of the "corn."

If it were a simple bruise, such as sometimes is produced through shoeing, the trouble would pass off gradually, as does also the change in color of the horn.

If it were a rupture of blood vessels, the shock to which it would be attributed must be something immense, and the extravation should occur very suddenly, for there is nothing in the anatomy of the parts and their general make-up, that predisposes to vascular rupture, even in the most energetic movements of the animal.

To go into the minute anatomy of the hoof would require a pretty large volume in itself; therefore, I can only say categorically, that rupture of the blood vessels supplying the horn cannot occur through any ordinary movement of the foot or limb, unless the union of the hoof with its foundation the ospedis,

* In the year 1875, during the performance at the great Roman hippodrome of P. T. Barnum, Esq., several animals that were used in the horse excercises of the ring, without shoes, suffered from laminitis of every grade.

through the elements of the keratogenic membrane, permitted of a rotatory movement.

There is no such rotation of the hoof on the organs within, and that disposes of the rupture theory.

The union of structures through the keratogenic membranethough elastic-is yet so strong and complete, that rupture of blood vessels is impossible, without a lesion of such extent that it would make itself felt immediately. Of course this has reference to the foot in health.

It is to the diseased condition of this laminal structure that we must look for the distant cause of the worst cases of "corn," as well as of another condition akin to corn, known to horsemen as "broken bar." If these structures were not diseased, how could the descent of the processes of the ospedis, or of the cartilages occur, which by pressure on the structure between them and the horny sole, are the factors immediately concerned in producing both affections?

The sole lying in the re-entering angle, between the bar and wall, could no more become affected by internal pressure than the anterior or middle portions, as long as the natural suspensory power was intact. This easily ascertainable fact appears to have been overlooked by nearly all English authorities on the foot.

In reality the pathological causation of corn differs from that producing laminitis, only in the locality at, and the extent to which the foot becomes affected.

As no one would claim that the shoe is always the cause of laminitis, as little could the shoe be blamed as the universal cause of corn. It will be observed that if we follow it from the start to its very worst termination, "corn" presents many analogies to laminitis. In the latter we have first the irritation, then the inflammation, which, if continued, destroys the adhesion of the horn to the vascular membrane. The suspensory power once lost, it can never be regained at that part, without a regeneration from above downward. By loss of the suspensory power, the ospedis descends on the villous tunie, or sensitive tissue. secreting the sole; this pressure being prejudicial, it causes a local death of the tissue, horn secretion stops, and the natural exfolia