merly been used, I found many of them very long, with nine or ten nails in them, and these pretty close together, and chiefly at the heels; by which there was double the risk of laming the horses in shoeing, and double the tendency to impede their going, by the heels being bound, so as to prevent their spring."

I am, however, open to confess, that I think Mr. Bracy Clark's writings, which relate to the anatomical structure and functions of the horse's foot, will amply repay the student for his time in reading them repeatedly; but with regard to this gentleman's views of the pathology of that organ, I am completely at issue with him.

The points of difference between us I shall endeavour to explain, at a future opportunity, in another paper, which will embrace the general diseases and accidents to which the horse's foot is liable.

method of shoe

at the present

I have now a few observations to offer in illus- Evils of the tration of the baneful effects of iron and nails upon ing, as adopted the elastic foot of the horse. In the discussion day. which followed my two papers on the Nature of the Navicular Joint Disease, its Causes, Symptoms, and Treatment, it will be remembered by many gentlemen present, that I proved to demonstration a pathological fact, which was doubted by most of the members then present; by some most strenuously denied, and ocular demonstration demanded: of course, this mandate was instantly obeyed; and

on unsheathing the weapons several diseased, contracted feet appeared, and in contrasting them with healthy, open feet, I satisfactorily proved to a numerous meeting of this Society, an unnatural position or elevation of the coffin bone within the hoof. Assured of the frequency of the occurrence of this altered position of the foot bone in feet which had been shod, and particularly with those horses in which the ordinary precautions for preserving the elasticity of the horn, through caprice or neglect, had been omitted, I am led from these data to the following deductions: 1st, That the common method Instantaneous of affixing the shoe by nailing to both sides of the function of the hoof has an immediate tendency to destroy the equilibrium or just balance of the weight when conveyed to the hoof.

limitation of

elastic laminæ.

The five hundred elastic laminæ or plates which surround the coffin bone, in conjunction with a corresponding number of horny lamina lining the crust, are known to be the sustainers of the superincumbent weight in the unshod natural foot, by forming a sort of dove-tailed union of immense strength. These numerous elastic springs elongate under the impression of the weight in direct ratio to the momentum or force, and which is accompanied with a corresponding relaxation or yielding of the horny box throughout at the same instant; by which concussion to the foot is obviated, and the animal himself preserved from jar.

On the other hand, we will suppose a three

year old colt, and, to avoid extremes, instance the hackney size, three parts bred, with well-formed limbs, and sound hoofs of becoming size, neither too flat and low, nor too upright and strong, to be well shod in the ordinary way for the first time, and with a seated shoe of equal thickness toe and heels, secured by eight nails, four on each side or quarter, as usual. From the very first moment that this animal steps out of the forge upon the new surface interposed between his foot and the ground, his tread becomes uneven, although the foreign body which is appended to the foot is perfectly level. Now the elastic laminæ also sustain the weight in this fresh-shod colt, the impression of which has a tendency to elongate the lamina to the same extent; but no, the fetter is upon the foot, and the best formed shoe that the art of man can devise, if nailed to both sides and quarters of the hoof, according to the mode in general use, will, from that very hour, limit, though it cannot altogether deprive the lamina of their elongation. The lamina covering the anterior and lateral portion of the coffin bone, will, on the instant, suffer some deprivation of function, just barely sufficient to disturb the harmony of the mechanism. The horny sole, however, notwithstanding the rigidity Partial or imof the shoe and nails, will continue to descend in of sole. part, and will yield to the impression of weight and force united. It is this partial or imperfect

perfect descent

Freedom of expansion enjoyed by the unshod foot.

descent of the coffin bone and horny sole to which I am anxious to draw your attention.

It is quite obvious that the unshod horse in a state of nature exercises equally the whole five hundred laminæ or elastic springs; by their elongation the coffin bone descends within the crust, under the impression of weight, from which pressure on the horny sole its arch sinks, and spreads uniformly in all directions, toe as much as heel, whilst every portion of the coffin bone which is in contact with the wall or crust also assists in dilating the base of the foot, and expanding the toe as well as the heels. The weight being removed, all these parts, by virtue of their own elasticity, instantly return to their former position, in readiness for renewed action; and undoubtedly the elasticity of the crust, the flexibility of the sole, frog, and bars, together with the expanded form of foot, are mainly preserved by this mechanical up-and-down motion, which, it should be remembered, with a horse left in his natural state is almost perpetual.

From the moment the colt is shod and nailed in the general way, on both sides, just so much of the coffin bone as is embraced by the portion of crust or wall which has received the nails, is limited in its descent, and a corresponding number of the elastic laminæ have their action also curtailed; but daily experience shews their office is not altogether

Diminution of

horny lamina,

to their impair

ment of func

tion.

suspended, even by the most gross shoeing; but the iron and nails together prove the most rigid fetter, in proportion as each nail has its antagonist immediately opposite on the other quarter of the foot. The consequences of this innovation on nature are these: at no very distant period from sensible and the first shoeing, the sensible and horny lamina in direct ratio become contracted; but as they remain entire in their organization, no pain ensues, the sole gradually becomes preternaturally arched, and the capacity of the horny box is by so much diminished; ; but yet this is not generally attended with pain, Consequent for nature as gradually adapts herself by her own of the horny resources to the change; the coffin bone actually natural arch. grows to the altered shape of the hoof by absorption and deposit; and thus is the fetter repeated month after month; and perhaps years pass away before Capacity of the actual lameness is established, though in too many minished. instances the reverse is the case.

Every individual horse thus shod is exposed to one of the principal predisposing causes of lameness, by the tendency it has, in conjunction with other causes, to elevate the coffin bone within the hoof, from limiting the action of these highly elastic springs, and also favouring that protrusion of the frog within the foot, before described: the ravages which succeed to this state of the organ, should the navicular joint happen to be bruised in its sudden descent against these deformed and in

encroachment

sole, its preter

horny box di