THE HORSE IN MOTION. 8l 



of the femurs low down to push more directly, in the former, on the 

 contrary, the centre of motion corresponding to the head of the 

 femur is not at the shoulder, but as high under the withers as pos- 

 sible, and the application of the propulsion as low as possible, as 

 was shown when describing the action of the great pectoral ; for, 

 the foot being the fixed point, the nearer the power is applied to it 

 the greater will be the velocity of the upper end of the extremity 

 acting as a crutch. 



In the extreme of flexion and extension, as represented in leaping, 

 the muscles act at great disadvantage, as is illustrated by the difficulty 

 and slowness with which an animal rises from a recumbent posture. 

 They are positions incompatible with speed. 



Whether the muscles act with the greatest energy at the earlier or 

 later stage of contraction has not been determined with certainty as 

 far as I know. There is no doubt, however, that they act with the 

 greatest promptitude in response to the will when the limbs are 

 slightly flexed. Boxers will instinctively put themselves in tliat po- 

 sition when in attitude for offence or defence. Boys when about 

 to start for a race will relax their extensors to get a good send-off, and 

 they do not fully extend them again until the trial of speed is over. 

 So the horse in fast trotting " settles to his work," as it is technically 

 called. In this expression it is intended to represent the idea that 

 the centres of motion are nearer the ground in order that the muscles 

 shall act to the best advantage, and that in propulsion the act shall be 

 most direct and longer sustained ; or, in other words, the points of 

 action and reaction are in a line forming a more acute angle with 

 the ground. 



M. Weber asserted that the velocity in walking will be greater the 

 nearer the head of the femur is to the ground ; as this height in- 

 creases the velocity decreases. One sometimes arrives at a truth by 

 a very devious route, though he may ha\e lost himself on the way. 

 He proved his position by the pendulum, which has been made to 

 demonstrate many a knotty ]:)roposition ; but while the leg of his 

 physical horse has swung three feet, our living horse has gone forty, 

 and his extremities have performed two complete revolutions. The 



