■"HE COFFIN-BONE. 299 



the unshod horse is always so. The practice of cutting much of 

 it away in shoeing, is therefore highly improper. 



The rough and detached parts should be cut off at each shoe- 

 ing, and the substance of the frog itself, so as to bring it just 

 above or within the level of the slice. It will then, in the de- 

 scent of the sole, when the weight of the horse is thrown upon 

 it in the putting down of the foot, descend likewise, and pressing 

 upon the ground, do its duty ; while it will be defended from the 

 wear, and bruise, and injury that it would receive if it came upon 

 the ground with the first and full sliock of the weight. This will 

 be the proper guide to the smith in shoeing, and to the proprietor 

 in the direction which he gives. 



THE COFFIN-BONE. 



The Ulterior part of the foot must now be considered. The 

 lower pastern, a small portion of which (see d, Fig. 37) is con- 

 tained in the horny box, has been already described, p. 267 — Be- 

 neath it, and altogether inclosed in the hoof, is the coffin-bone, or 

 proper bone of the foot, (see /, Fig. 37, and d, Fig. 38). It is 

 fitted to, and fills the fore part of the hoof, occupying about half 

 of it. It is of a light and spongy structure (see d, Fig. 38), and 

 filled with numerous minute foramina (holes or pores). Through 

 these pass the blood-vessels and nerves of the foot, which are ne- 

 cessarily numerous, considering the important and various secre 

 tions there carrying on, and the circulation through the foot which 

 could not possibly be kept up if these vessels did not run through 

 the substance of the bone. Considering the manner in which 

 this bone is inclosed in the horny box, and yet the important sur- 

 faces around and below it that are to be nourished with blood, the 

 circulation which is thus carried on within the very body of the 

 bone is one of the most beautiful provisions of nature that is to 

 be found in the whole frame. No inconvenience can arise from 

 occasional or constant pressure, but the bone allows free passage 

 to the blood, and protects it from every possible obstruction. 



Its shape and position within the foot will be seen by inspect- 

 ing Fig. 37. 



On the front and sides of the coffin-bone are laminae or leaves 

 — cartilaginous fleshy plates — running down between the horny 

 leaves of the crust. The substance which connects these leave 

 with the coffin-bone is highly elastic — and necessarily so — as 

 while the horse is at rest, his whole weight is supported by them. 

 This has been proved by experiment. The sole, bars, and frog 

 were removed from the foot of a horse, and yet as he stood, the 

 coffin-hone did not in the slightest degree descend. But when 

 th« .horse is moving, both sets of leaves — those of the coffin-bone 



