28 



ANATOMY AND PHYSIOLOGY OF 



the sole. The horny substance of the wall 

 is resolvable into fibres, bearing a resem- 

 blance to thick or coarse hairs, wliich in the 

 entire hoof are so intimately matted and 

 glued together, as to have the appearance 

 and strength of solidity. By close and ac- 

 curate inspection these fibres may be seen 

 descending in parallel lines, taking the 

 obliquity of the wall, from the coronet to 

 the inferior or solar border ; they do not run 

 promiscuously, but are arranged in rows, 

 forming sorts of beds or strata, lying one 

 upon another — a disposition made manifest 

 in the foot of the foetus. A clean-cut trans- 

 verse section of the wall exhibits upon its 

 surface numerous minute, circular, whitish 

 spots, which grow larger and more distinct 

 towards the internal part, and through a 

 glass appear to be hollow or tubular. 

 These spots I take to be produced by sec- 

 tions of the horny tubes, apparently contain- 

 ing a whitish matter, a sort of pith, or pulp, 

 or gelatinous instillation which pervades 

 them from their origin from the villi of the 

 coronary circle ; the same as hairs derive 

 their unctuous matter from the bulbs pro- 

 ducing them, and (as this matter does the 

 hair) renders the horny fibre tough and 

 elastic — in fact, imbues it with the peculiar 

 attributes so well known to smiths by the 

 appellation of living' horn ; the epithet 

 " living " being here used to denote the ob- 

 vious differences the hoof of a living animal 

 evinces from one that has been long detached 

 from the body, or that is dead. We are too 

 apt to believe that the various agents known 

 to act upon the dead hoof or horn must 

 take similar effect on the living ; and upon 

 this erroneous belief we employ hot and 

 cold water, etc., etc., in treating disease of 

 the feet, forgetting that we have opposed to 

 our remedies the resisting or self-preserving 

 properties of living horn. 



" The sole, as well as the wall, is fibrous 

 in its structure ; but its fibres appear to be 

 of a finer quality, and, in course, are very 

 much shorter : they, however, take an ob- 

 lique direction, from behind forwards, fol- 

 lowing the same degree of slope as those 

 of the wall. They issue from the villi 



penetrating the superior surface. To the 

 fineness of its fibres, combined with the rel- 

 ative magnitude of the tubular canals, and 

 consequent proportions of horny and gela- 

 tinous substances, may be ascribed the 

 comparative softness and elasticity of the 

 sole. 



" The frog, however, displays these 

 qualities in such a remarkable degree as to 

 appear, in fact, to be composed of quite 

 another kind of horn ; though, on examina- 

 tion, we find it to evince the same fibrous 

 structure, the only perceivable differences 

 being the comparative fineness of the fibres 

 and their proportionably greater tubularity : 

 their direction is oblique, correspondent with 

 those of the wall. 



"production of the hoof. 



" The wall is produced by the coronary 

 substance, a sensitive and glandular part we 

 shall have occasion soon to examine. Its 

 villi, by some peculiar, mysterious, secretory 

 process, convert the blood circulating 

 through them into a soft pulpy gelatinous 

 matter, which by exposure becomes hard 

 horn, descending from the villous point that 

 produced it, in the form of a tubular fibre, 

 down to the sole. The fibres are united 

 together at their very origin, but their tubes 

 or canals diminish, the lower they descend ; 

 which accounts for the porous or honey- 

 comb-like structure of the interior of the 

 coronary border and the comparative solidity 

 of the parts below. The outer layers or 

 strata of fibres are found to be more com- 

 pact and of closer texture than the inner; 

 which arises, in part, from the villi produc- 

 ing them being removed to a greater dis- 

 tance, and to the comparative smallness of 

 their canals, and which, consequently, the 

 sooner become obliterated. The use of 

 Mr. Clark's coronary frog-band becomes 

 now more apparent, serving, as it evidently 

 does, to cover and protect these external 

 fibres until they grow sufficiently firm and 

 solid of themselves to bear exposure and 

 resist casualties. 



" The sensitive laminae make no addition 

 to the substance or thickness of the wall : 



