·viz., the pulpy substance, commonly called the fatty frog or elastic cushion, becomes in part absorbed. The cartilaginous or reticular portion, being a harder body, remains; therefore, it still retains its form in a condensed state, and is yet an elastic sub- Absorption of stance, although degenerated into a hard bed in stead of a soft one. Thus it is that that portion of the main back sinew of the leg, the flexor perforans tendon, where it forms the navicular joint, is no longer embedded in such an elastic medium as would defy all human ingenuity to imitate, which was the original and healthy condition of the fatty frog. The dilapidated state of this spring affects the elasticity of the posterior parts of the foot in other ways besides the resistance it opposes to the navicular bone in its descent; for I believe the fatty frog, as it is called, to be an organ which performs several important functions, as regards elasticity alone, and that there is an additional reason for the larger half of this elastic mass being placed posterior to the navicular joint, besides that of expanding the lateral cartilages from its continuity. For when we consider the extensive pulley-like motion between the tendon and the navicular bone, and that all the upper part of this pulley-like surface, from the oblique position in which the bone is placed, could not be benefitted by a spring immediately under it; and taking also into the account, the fatty frog. that the navicular bone, in its descent, must incline backward, in unison with the motion of the coffin bone, it follows, that a soft pillow was as much required at the back as at its base: and, indeed, a more extensive one, as the back part of this surface presents a larger space than the inferior. Notwithstanding all this difference between the soft bed and the hard one, still it cannot be denied that there are many thousand horses in this country so circumstanced, which travel perfectly free from lameness; though I much doubt if any one of them retains the full degree of elasticity in action which he originally possessed. But the absence of lameness is by no means a proof of the harmlessness of this antecedent disease; for the navicular joint of such a foot, although sound as adamant, and its surfaces polished like ivory, and duly lubricated with synovia, is in jeopardy, and only requires two or three more concurring circumstances to effect a lesion within its delicate organization; and this frequently happens instantaneously. Rigidity of foot I conceive that the rigidity of the posterior parts of the foot (the navicular joint not having suffered any injury) conveys to the animal the sensation, not of pain, but merely slight restraint or compression, which is attended with a corresponding want of confidence, that induces him to give an undue bias to the weight towards the toe or front of his foot; the lamina of the fore part of the coffin bone sustaining the burden, while the navicular bone and heels of the coffin economically receive only so much of the superincumbent weight as the degenerated harsh spring may be able to dispose of; and therefore a condition of the foot is produced which approaches to disease. Thus, I think, may be solved the greatest of all mysteries regarding excellence in the movement of this incomparably useful animal, viz. that a valuable horse, highly gifted with action, and in the prime of life and spirits, suddenly ceases to convey to the rider that indescribable pleasant sensation which had always before distinguished him from common horses; his action becomes li- Diminished elasticity withmited in his slow paces without any apparent cause; out lameness. and yet his mode of going might defy the competent veterinarian to pronounce him lame, although brought cool from the stable on the pavement; and the owner is the more perplexed, in proportion as he himself attempts to ascertain the cause. If the horse happens to be a fast trotter, he tries him for a spirt; and is impressed with the idea that he never performed his mile in less time in his life. If, instead of a trotting horse, it be an accomplished hunter, he returns from the chase, and exclaims in ecstacy, "We have gone the best pace without a check, and he has carried me brilliantly!" when, perhaps, on the preceding day, he had ridden him five or six miles, at a walk or slow trot, and re . turned thoroughly disgusted with him; for, instead of performing with his wonted grace and elegance in a firm, flat step, not only regardless of the weight of his rider above, but equally as independent of the stones below, he shuffled, broke frequently from the walk into a jog, dropped occasionally, and now and then dug his toe or pegged it against a stone, a failing before unknown with this faultless animal. Under these inauspicious circumstances, the style of his slow trot, to a by-stander, would appear only on a level with that of a sound horse possessing merely the ordinary degree of action, so that the owner would be the only person aware, from his knowledge of the previous merits of this animal, that he had lost any thing. Now, you will natuLoss of equili- rally ask, What has he lost? I answer, the equili brium or na ment of the su tural adjust- brium or natural adjustment of the superincumbent perincumbent weight, the lamina in front of the coffin bone sus weight. taining an undue proportion, whilst the function of the laminated structure of the bars and heels is limited, or partially suspended. Hundreds of horses, and even young ones, are annually sold in London as sound which have suffered this deterioration, in defiance of the most scrupulous examinations as to soundness. Now you will contend that, in the case I have proposed, of the horse being capable of trotting at the rate of twenty miles an hour, or being a weightcarrier up to the fleetest hounds, that he must pos sess elasticity:-granted; but the question is, not what he now has, but the degree of elasticity he once possessed; and we can judge of perfection only by comparison. Even a confirmed groggy horse, incurably lame, might be selected to accomplish one or other of the feats I have just mentioned; though I must acknowledge it would put in requisition the rare remains of one of Nature's masterpieces: still such a description of horse is to be found. It therefore appears, that an incipient defect of this kind may, under certain circumstances, alter the animal's action without occasioning lameness; and that a horse, either of breeding or of good mettle, when called into quick movement, has his energies so far excited as to be totally regardless of the rigidity of this spring; that is, supposing the navicular joint to be unimpaired. Gentlemen, I fear you will think me prolix, especially as the object of this paper is the treatment of disease; but I cannot forbear, since this is the precursor from which the foot is suffered still further to degenerate, oftentimes for many months, before the most attentive observer thinks of consulting us (being unconscious of any disease existing), where- The precursor by our skill is frequently baffled in the treatment of lameness. the other formidable malady, which sooner or later supervenes. Moreover, the public have never been sufficiently warned of this antecedent disease by any D to navicular |