27^ I*HE HORSE. 



the inside of the hock ; the larger wedge-like bone e above ; and the mid- 

 dle f, and the smaller one below, and it will be seen that almost the whole 

 of the weight of the horse, communicated by the tibia «, is thrown upon 

 these bones. The cube-bone d does little more than support the point 

 of the hock c. It is then easy to suppose, that in the concussion of hard 

 work or rapid travelling, these bones, or the delicate and sensible membranes 

 in which they are wrapped, may be severely injured. Repeated dissections 

 of horses that have been incurably lame behind, without any thing external 

 to point out the place or cause of lameness, have shewn that inflammation 

 of the membranes lining these joints, and secreting the fluid that lubricates 

 them, has taken place; and has been accompanied by all the pain of joint 

 disease, and evils corresponding to those which we have described, 

 when treating of broken knees, and the consequent inflammation of the 

 membrane and internal part of the joint. Indeed, so clearly is this 

 jiow established, that when, after careful and repeated examination by a 

 jcompetent person, no seat or cause of lameness can be discovered, we 

 shall be right nineteen times out of twenty, in deciding that it is disease in 

 this portion of tlie hock. No enlargement, no heat, will indicate its exist- 

 ence, but when it has been long established, and ossified matter has been 

 thrown out between these bones, it will, like the true spavin, spread, and 

 appear either on the inside of the hock, or surrounding the whole of the 

 joint. 



In these cases, then, of mysterious lameness, and when, after the 

 remoyal of the shoe, and the most patient search, we have failed in dis- 

 covering a cause of lameness elsewhere, w^e shall be justified in considering 

 this as the affected part, and treating it accordingly: and as the injury is 

 deep, and in the very centre of the joint, we must adopt severe measures 

 in order to reach it. We must blister immediately, and repeat the blister, 

 and enjoin perfect quietude and rest ; but here, as in the bone-spavin, 

 and oftener than in that disease, all our appliances and means may be 

 fruitless. Our only hope lies in an early attempt to combat the evil; 

 and in all these obscure cases, he is unjust to himself who does not 

 speedily have recourse to their advice, to whom science and practice have 

 given a facility in detecting latent disease. 



THE POINT OF THE HOCK. 



If the reader has not forgotten what we have said concerning the projection 

 of the elbow, he will be convinced that the form of the hock is materially 

 connected with the value of the horse. The most powerful of the flexor 

 or bending muscles are inserted into the point of the hock, or the ex- 

 tremity of the OS calcis c; and in proportion to the projection of the hock, 

 or, in other words, the length of this bone, will two purposes be effected. 

 The line of direction will be more advantageous, for it will be nearer to a 

 perpendicular ; and the arm of the lever to which the power is applied will 

 be lengthened, and mechanical advantage will be gained to an almost 

 incredible extent. Suppose this bone of the -hock to be three inches in 

 length ; the joint formed by the tibia and the astragalus is evidently the 

 centre of motion ; and the weight, concentered about the middle of the 

 shank, is the obstacle to be overcome. If the weight be four times as far 

 from the centre of motion as the power, a force equal to four times the 

 weight would raise it. It is, however, here to be remembered, that it is 

 not merely the weight of the leg wbich is to be raised, but the weight of 

 the horse, for the time resting upon the leg, and that weight to be pro- 

 pelled or driven forward. At what shall we calculate this? We may 



