Narrow heels not necessarily box; secondly, a thoughtful, steady master; thirdly, a farrier who will carefully shorten the toe, lower the heels, and pare the sole to a nicety, at the expiration of every three weeks; but this farrier must also be an artist sufficient to make a seated shoe of an equal thickness heel and toe (which latter may be slightly elevated), and he must secure the shoe by nailing all round the toe, and avoiding the inside heel, and even the quarter. I am convinced that a sound horse with narrow accompanied heels (if managed in the way I have just described) may be preserved free from the navicular disease to the latest period of life. by lameness. By taking all these precautions, with the continuance of gentle motion in a loose stable, the hoof How avoided. will become elastic, and its elasticity be preserved: the sole and bars, not acquiring an undue thickness, will be at all times susceptible of the natural impression from the coffin and navicular bones, and will yield under the superincumbent weight, and give room for the navicular bone and tendon not only to descend obliquely backwards, but also leave free space for the back action or pulley-like motion of the tendon against the bone at the instant the flexor perforans muscle, by its powerful contraction, lifts the foot again from the ground. Thus the partial pressure or contraction on this important joint being prevented, the general contraction of the hoof is rendered comparatively harmless. 25 SECOND PAPER; VETERINARIAN, VOL. III, p. 24. THE SYMPTOMS AND CURE OF NAVICULAR DISEASE [Read at the Veterinary Medical Society, December 4, 1829.] GENTLEMEN, In the month of December of last year, I had the honour of reading to this Society a paper explanatory of my views regarding the nature of the navicular disease, or chronic lameness in the fore feet of horses, together with the causes of that destructive malady. The method of treatment and cure is the object of the present paper for this evening's discussion. cognized by the This very prevalent complaint, commonly called The term, navicular joint groggy lameness, has been shewn to exist gene- lameness, rerally in the navicular joint; and I think I may profession. safely assert, that the term navicular lameness has now become as current among veterinary practitioners as coffin lameness used to be among the ancients. Although dissection generally affords satisfactory evidence of the seat of disease, yet it does not as uniformly serve us in tracing its causes, the investigation of which is generally involved in more obscurity, and consequently is too often speculative. But with respect to the probable causes of the disease in question, I think there is as much light elicited by the dissection of the morbid specimen as we could desire. Commencing with the ground surface of the horny frog, and unfolding, layer by layer, all parts, until we arrive at the carious surface of the navicular bone, there will be presented, at one view, that which not only fully explains all the phenomena of the disease, but suggests to us the method of cure, and even points to a rational mode of shoeing. I beg to observe, that in my former paper I undertook a sort of classification of contraction, or rather its division into two kinds; the one under the designation of simple or general contraction, such as the narrow-heeled foot with lengthened toe, so very prevalent, and obvious to the common observer; and which is frequently seen unaccompanied with lameness, and even sometimes remains harmless through a long life of hard work. The other I have called the occult or partial contraction, which is one of the most insidious diseases to which the horse is Specious ap- subject; and so specious is the exterior of such a foot, that none but a most experienced eye would discover the existence of any disease, unless attracted to it by an accompanying lameness; circularity, solidity, compactness of fibre, and an unusual appearance of strength, being its characteris pearances of some hoofs. tics. The heels are high, the sole strong, and the crust thick, particularly at the toe; but it sometimes loses its due proportion of obliquity, and becomes rather more upright than natural. There is, however, a more certain indication which usually presents itself; viz., a falling in of the inside quarter, or slight indentation about the middle of the crust towards the heel: this sometimes assumes the appearance of a stricture, in a slight degree, all round the crust, and occasionally two or three of these strictures or rings are apparent. Thus much may be observed without the removal of the shoe; but the protrusion of the frog within the foot (adverted to in my former paper), together with the morbid concavity of sole, may not be discoverable till the drawing-knife has been extensively employed, not only on the sole, but in excavating those channels or commissures on each side of the frog, between it and the bars. An inordi- Diminished nate growth of sole and other parts of the foot, by often concealed by a prominent presenting prominent surfaces, too often conceal exterior. from our view the encroachments and consequent diminution of the horny cavity. The outer surface of the sole of such a foot sometimes resists the drawing-knife like a stone, from its excessive hard ness. ge I contend, that the navicular joint disease is nerally, though not always, preceded by one of these contractions of the horny box. It may be the ge area of the hoof Occult contrac neral contraction first described, or this occult partial contraction. There will be found an ascent of the coffin bone within the hoof, occasioned by the contraction: it is the elevation of this larger foot bone which necessarily puts its small companion, the navicular bone, in jeopardy. I say, necessarily; because they are so closely knit together by ligaments, that the smaller bone bears the resemblance of a process to the larger. The occult contraction is chiefly to be dreaded from below up- for these obvious reasons: it occasions a more par tion of the hoof wards, the most serious encroachment. tial pressure, is frequently more rapid in its progress, and, by operating principally from below upwards, has a greater tendency to elevate the coffin and navicular bones. On the contrary, the simple or general contraction is a more lateral compression, and so slow in its encroachment, that it affords, perhaps, one of the most striking instances in the animal creation of Nature's resources, when contending against hostile agencies, if she is not too abruptly violated. This is completely verified in the contracted foot of an old hard-worked horse, free from lameness. Nature appears to have had time to adapt herself to the change, without inflammation being induced, in that degree, however, sufficient to occasion pain. The most obvious effect of contraction, whether of the simple or occult kind, appears to be absorption; |