400 THE COFFIX-BOXE. 



again to their natural state ! In this vie"vs% therefore, the horny frog is a 

 powerfal agent in opening the foot ; and the diminution of the substance 

 of the frog, and its elevation above the ground, ai^e both the cause and 

 the consequence of contraction — the cause, as being able no longer power- 

 fully to act in expanding the heels, and the consequence, as obeying a law of 

 nature, by which that which no longer discharges its natural function is 

 gradually removed. It is, however, the cover and defence of the internal 

 and sensible frog, which will be presently treated of ; enough, however, 

 has been said to show the absurdity of the common practice of unsparingly 

 cutting it away. In order to discharge, in any degree, some of the offices 

 which we have assigned to it, and fully to discharge even one of them, 

 it must come in occasional contact with the ground. In the unshod horse 

 it is generally so ; but the additional support given by the shoes, and more 

 especially the hard roads over which the horse is now compelled to travel, 

 render this complete exposure of the frog to the ground not only un- 

 necessary, but injurious. Being of so much softer consistence than the 

 rest of the foot, it would be speedily worn away ; occasional pressure, how- 

 ever, or contact A\'ith the ground, it must have. 



The rough and detached paints should be cut off at each shoeing, and the 

 substance of the frog itself, so as to bring it just above or within the level 

 of the shoe. It will then, in the descent of the sole, when the weight ot 

 the horse is throwTi upon it in the putting doMTi of the foot, descend like- 

 wise, and pressing upon the ground, do its duty ; Avhile 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 shock 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 latter should often look to this, for it is a 

 point of very great moment. A few smiths carry the notion oi frog jJi'es- 

 sure to an absurd extent, and leave the frog beyond the level of the sole — 

 a practice which is dangerous in the horse of slow draught, and destinic- 

 tive to the hackney or the hunter ; but the majority of them err in a 

 contrary way, and, cutting off too much of the frog, Hfb it above the 

 ground, and destroy its principal use. It should be left jhist above, ot 

 within the level of tlie sJtoe. 



THE COFFIN-BONE. 



The interior part of the foot must now be considered. The loAvei 

 pastern, a small portion of Mdiich is contained in the horny box, has been 

 already described, p. 378 ; beneath it, and altogether enclosed in the 

 hoof, is the coffin-bone, or proper bone of the foot. It is fitted to, and 

 fills the forepart of the hoof, occupjnng about half of it. It is of a light 

 and spongy structure, (see d, fig. 1, page 378), and filled with numerous 

 minute foramina or holes. Through these pass the blood-vessels and 

 nerves of the foot, which are necessarily numerous, considering the im- 

 portant and various secretions 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 enclosed in the horny box, and yet the important sur- 

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

 tion which is thus cai'ried 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. 



The forepart of the coffin-bone is not only thus perfoi'ated, but it is 

 curiousl}' roughened for the attachment of the numerous minute lamiu.'B 



