The Locomotor Apparatus. 333 



to the corona and pedis, receiving also a slip from the sus- 

 pensory ligament, and extensor suffraginis to the suffraginis. 

 This latter receives a strong slip of ligament from the out- 

 side of the carpus, which entirely takes off the strain from 

 the muscle, and keeps the tendon taut during sleep. The 

 action of the tendons and ligaments of the hind- leg in the 

 act of standing has been described on p. 325. 



When a horse falls at a walk or trot, he injures his knees ; 

 but when he falls (which is sometimes the case) through 

 sleeping standing, he invariably damages his fetlocks. 



Locomotion. — We have next to study the question of 

 locomotion in the horse, and describe how the legs are 

 moved during the different paces. It will be remembered 

 that our knowledge of this subject chiefly depends upon 

 instantaneous photography, the pioneers in the field being 

 Stillman and Muybridge.* 



The axiom laid down by Stillman is that ' perfect 

 quadrupedal locomotion requires uniform support to the 

 centre of gravity, and continuous propulsion by each 

 extremity in turn.' 



The Walk is the slowest pace, and is executed in a per- 

 fectly definite manner. In the first stage the body is 

 balanced on three legs, in the second stage on two diagonal 

 legs, in the third stage on three legs, and in the fourth on 

 two lateral legs, and the next movement brings us back to 

 the first stage, only with different legs employed (Fig. 37). 



We will now trace the movements in each stage : The 

 horse advances one fore-leg — say, the off (1) — and he is 

 left standing on the near fore, near hind, and off hind — 

 this is the first stage ; in the second stage the near hind is 

 picked up, and the animal is standing on the near fore and 

 off hind, viz., on diagonal legs (2) ; in the third stage 

 the off fore has come to the ground, and the animal is 

 balanced on both fore and the off hind legs (3) ; in the 

 fourth stage the near hind is advanced to be placed over, 

 or in advance of, the track of the near fore ; to make room 

 for it the near fore is advanced, and the horse is left stand- 

 * ' The Horse in Motion.' 



