THE HORSE. 



27 



the same degree augments the substance of 

 the heels, occasioning that swell of them 

 which has suggested the appellation ' bulb.' 

 The horny band itself is everywhere lamel- 

 lated upon its internal surface ; but these 

 broadened parts of it display lamellse of a 

 much bolder character, and consequently 

 render their union with the heels so much 

 the more intimate and enduring. The in- 

 ferior edge of the band is denticulated, and 

 the denticulations become so interlaced 

 with the lamellated fibres of the wall, that 

 their union is rendered, in the ordinary 

 state of the hoof, altogether imperceptible. 

 For drawing our attention to this part^we 

 are indebted to JVIr. Clark; and, insomuch 

 as he considers it to be a production of the 

 cutis (not having any connection with the 

 glandular circle that secretes the wall), and 

 to serve the purpose of * uniting the sensible 

 parts with the insensible,' I agree with him. 

 I find something very similar to this grow- 

 ing upon the human nail, issuing from the 

 superior edge of the terminating border of 

 the cutis, and continued from the cuticle, 

 which proceeds for some way upon the nail, 

 uniting it more closely and firmly with the 

 cutis, and protecting the latter from exter- 

 nal injury. This production is no more the 

 beginning of the nail itself than is the so- 

 called /roo'-band the commencement of the 

 wall : they are both distinct parts, though 

 but supplementary ones, and seem to be of 

 a nature partaking both of horn and cuti- 

 cle. It has no more important relation to 

 the frog, in my opinion, than it has to the 

 wall : it serves the same purpose to both, 

 — that of strapping up the heels of the 

 frog and binding them in closer and more 

 intimate connection with the neighboring 

 parts. Were I asked what other use it ap- 

 peared to have, I should say, that it was 

 formed to cover and protect from injury the 

 neW'for?ned horn of the hoof, guarding it in 

 its passage downward, until it has acquired 

 substance and hardness sujEficient to resist 

 external impressions of itself. 



"development of the hoof. 

 " During the early months of fcEtality, no 



horn or hoof is to be found. The foot is 

 covered with a substance, white, firm, and 

 elastic, resembling cartilage in its appear- 

 ance, but proving more of the nature of 

 cuticle on examination, which supplies the 

 place of hoof. At the coronet this substance 

 takes its origin from the cutis, being found 

 to be continuous with the cuticle ; but that 

 which covers the bottom of the foot is a 

 production firom the sensitive sole and frog. 

 Altogether, it possesses the general form 

 and appearance of the hoof, differing how- 

 ever in these particulars — that the sub- 

 stitute for the wall is comparatively thin in 

 its substance ; while that which grows from 

 the bottom of the foot is enormously thick, 

 and, instead of being shaped into sole and 

 frog, exuberates to a degree to constitute 

 club-footedness. About the same period 

 at which the pastern and coffin-bones take 

 on ossification, horn makes its appearance 

 underneath this cuticular wall, in the form 

 of plates descending from the coronet, ex- 

 hibiting with peculiar distinctness the lamel- 

 lated structure. The horny wall becomes 

 considerably advanced before we perceive 

 any change in the bottom of the foot. At 

 length, horn is detected forming underneath 

 the cuticular substance, which, increasing in 

 thickness, gradually represents sole and frog. 

 Not, however, in an undeveloped state^ for 

 even at birth these parts are yet concealed 

 by the exuberant cuticular covering, now 

 become loose in its texture, and shaggy and 

 ragged, in consequence of not receiving any 

 further supply from the parts that produced 

 it, and of being near its decadence ; for it 

 not long after falls off, disclosing sole and 

 frog both ready formed. 



"structure of the hoof. 

 " Horn is found to differ in its texture or 

 quality, not only in the many animals in 

 which it is met with, but in different parts, 

 and even in the same part of the body of 

 the same animal. That which composes 

 the hoof of the horse is a remarkable ex- 

 ample of this. How different is the horn 

 of the frog from the horn of the wall ; and 

 yet neither of them agree in texture with 



