[08 HORN, HOW COMPOtlNDED: CONCOSSlONa 



He will also thus discern why I advise, in certain cases, the enveloping the 

 whole foot whenever the appHcation of a poultice becomes necessary to any 

 part of it. 



On completing the section, he will discover two branches of arteries which 

 descend into the foot at the coronet near the quarters and supplied the coffin- 

 bone (a), that occupies the cavity of the horny hoof, with fine blood for its re- 

 production. In other words, the formation of new horn is derived from the 

 blood, which is sent hither in good quantity, and pervades the internal part of 

 the coffin bone in particular. In this bone the operator will perceive a cavity, 

 or rather three hollows communicating with each other, in which the horny 

 matter is generated. Or, probably, this is the reservoir for such particles of 

 blood as are suited to the formation of hoof, as it may be required and called 

 for by the process of nature, and the demands of wear and tear, of rasping and 

 drawing inordinately, all which must subtract from its quantity, and leave the 

 bone comparatively hollow, and less fit for resisting the hard concussions to 

 which it is liable at every step. This fact may be ascertained by keeping a 

 bisected foot for a few months, when the moisture having left it in great mea- 

 sure, in the cavity of the coffin-bone will be found a yellowish glutinous sub- 

 stance precisely of the same nature and colour as that which fills the space 

 between the hoof and coffin-bone at cc^ in the section at page 166: without 

 odour and nearly tasteless, its uses are evidently the supply of new hoof. 



Seeing this curious construction of the foot, we are compelled to allow that 

 numerous accidents may also occur to prevent the supply of blood to the parts, 

 to say nothing of its unfitness at times to carry on its proper purposes. The 

 two vessels before noticed that bring this supply of new blood descend into the 

 foot behind the small pastern bone, and pass with the back sinew {k) under- 

 neath the shuttle bone (/i), as may be noticed in the section, at page 166. 

 Here it enters the coffin-bone at the sole, by an indentation of the bone de 

 signed for the protection of the vessels passing in and out. From the recep- 

 tacle in the coffin-bone, after concoction, the blood issues forth — part of it to 

 lubricate and nourish the shuttle-bone and its adjacent ligaments, the remain- 

 der to eflfect similar purposes elsewhere, but the greater part is destined to 

 supply the horny material of the hoof. 



Those "concussions" at every step, before spoken of, as affecting the action 

 of the shuttle-bone upon the posterior point of the coffin-bone, occasion trivial 

 injury at every step in quick motion ; more harm arises as the animal is much 

 pushed in his work ; then heat and fever of the foot supervene, contractions 

 follow, with a train of evils that have acquired diflferent names, thirty in num- 

 l»er, but which I have reduced by three-fourths, with a view to simplifying 

 the subject: most of these diflfer only in situation. Very hard concussions, 

 or a single injury of sufficient magnitude, produce lameness at once, which 

 most unaccountably received the name of "strain of the coffin-joint," and un- 

 der which general misconception I shall shortly give it a moment's considers 

 tion. 



The student who would push his inquiries farther will next turn his atten- 

 tion to the muscles, ligaments, and tendons, that guide the foot ; that lift it 

 up, and suffer it again to meet the ground ; that may perform these offices 

 firm and effectively, or being relaxed, diseased, or ill-formed, they and their 

 functions agree not with the well-being of the foot. Probably he will find it 

 convenient to lay open this part of the arcana of progression by the horse's 

 i«g (the lower part of it) previous to severing the foot itself, seeing thai the 

 subject will then be quite fresh, and that one part may intelligibly illusirate 



