272 THE HORSE. 



the inside ar* the hock ; the larger wedge-like bone e above ; and the imd 

 dley, and ihe smaller one below, and it will be seen that almost the whole 

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

 these bones. The cube-bone d does little more than support tiie poin; 

 of the liock c. It is easy then to suppose, tiiat in the concussion of hard 

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

 branes 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 shown 

 that inflammation of the membrane 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 inflam- 

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

 is this now established, that when, after careful and repeated examination 

 by a competent 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 the hock. No enlargement, no heat, will indicate its 

 existence, 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 

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

 covering a cause of lameness elsewhere, we 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 

 )f 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 fle.xor 

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

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

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

 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 lengtbenesl, 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 whicli is to be raised, tiut the weight of 

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

 elled or driven forward. At what shall we calculate this ? We mav 



