636 A MANUAL OF VETERINARY PHYSIOLOGY 



himself and forming his judgment of the obstacle. During the 

 steadying period he is getting ready to raise the fore-hand : 

 this he could not properly effect without a modification of the 

 pace ; he is also estimating at what point he should take off. 

 In Fig. 213, (1) and (2), the horse is seen steadying himself, bring- 

 ing the hind-legs well under the body, and raising the fore-hand. 

 In (3) the final upward push has been given by a fore-leg, and in 

 this process not only the fore-legs but the muscles of the back 

 and loins are playing a most important part. It is impossible 

 for a horse to rear even to the partial extent required for an 

 ordinary jump if the back is weak. In (3) the obstacle is being 

 faced, the animal is lifting the fore-hand and bending the knees, 

 the hind-legs being well under the body, in order to support the 

 weight. The next important point is the continued bending of the 

 knees in (4) and the straightening or extension of the hind-legs. 

 The moment the fore-feet are above the level of the obstacle, 

 propulsion forward with the hind-legs begins ; first both hind-legs 

 straighten themselves, extending to the utmost, while the limb 

 nearest the jump is left to give the final push off (5) and (6). It 

 is now the turn of the hind-legs to become flexed, the hocks bending 

 as much as the knees had previously done, while at the same time 

 the fore-legs now extend, with the object of making contact with 

 the ground. This contact must be made with a firm, straight 

 leg, one (6) followed by its fellow (7), which in (6) is seen placed 

 out in advance. It is advanced in order that the first fore-leg 

 to make contact (6) may be carried forward out of the way (7), 

 for it is occupying the place where the hind-feet will alight. 

 These now come down, first one, then its fellow, but before the 

 second hind-leg reaches the ground the fore-leg has already 

 pushed off (8). It will be observed that the jump resolves itself 

 into a partial rear, a doubling up of the fore-limbs and powerful 

 extension of the hind, followed by the upward push, the extreme 

 flexion of the hocks, the marked extension of the fore-legs, and 

 the reception of the weight of the body on first one and then the 

 other fore-leg. The jump reverses the use of the limbs in 

 ordinary locomotion ; there the thrusting is done by the fore- 

 legs, and the weight of the falling body is received on the hind ; 

 in the jump the hind-legs do the thrusting and the fore-legs 

 receive the weight of the falling body. 



In Kicking with both hind-legs (Fig. 214) the head is depressed, 

 a powerful contraction of the muscles of the quarters and back, 

 A A, throws the croup upwards, the hips are flexed through B B, 

 the stifles by the contraction of C C, and both legs are violently 

 extended through D D. No estimate of the force employed in 

 kicking can be made. A shell is not productive of more damage 

 than that caused by a determined kicker. It is no figurative 



