66 MATERIALS FOR A MEMOIR ON 



In the trottiDo;-horse the fore les; which is about to leave the 



ground is apt to interfere with the hind leg of the opposite side 



as it is advancing to come to the ground. In order to avoid this 



mishap the animal is trained to lift the fore legs to a degree which 



is not required in the walk. The motions of the animal suggest 



that the act of trotting as developed in the horse for fast gaits is 



artificial and is not especially useful for studies in locomotion. It 



has the same value as the study of the motions of a " trick-horse." 



(See p. 56.) 



The Back. 



That the rack is not a uniform gait is seen from the following 

 statements : 



In 594, in a series of twelve pictures, the animal stands on one 

 foot alone once ; is in the air in six ; and on laterals in five. 



In 595, in a series of the same length, one foot remains "on" in 

 three; laterals are "on" in six; and the animal is "off" in three. 



The transition between laterals is well seen in the series 593. 

 In the walk at least the transition between the laterals and the 

 diagonals is effected by the hind limbs. 



In racking the impressions made by the hoofs on the ground 

 are in regular alternation of front and hind feet. 



Pacing in the horse is a delicate motion, since any irregularity 

 of the ground interferes. The giraffe is a natural pacer. The 

 pace is often accepted by the dog. 



Transitions and Contrasts of Gait. 



The walk is the basis of the trot and the amble, which is in- 

 deed nothing but a running walk. The gallop leads to the run. 

 The run may be called an extended gallop. The amble and the 

 rack are trained forms of the gait. The walk often breaks 

 directly into the amble, and this into the gallop. 



The difference between the trot and the pace, as noticed in the 

 effect the positions of the limbs make on the eye, is but slight. 



In series 602, Fig. 4, the fore and hind legs on the right side 

 are both in forward strain. The fore leg comes down first, and is 

 instantly followed by the hind. If the two had come down to- 

 gether, we should have had the initial step of the pace. 



The trot and the walk are closely allied in all essential particu- 

 lars. The manner in Avhich the imprints of the feet are made on 



