526 THE EXTERIOR OF THE HORSE. 



rior member (3) belonging to this biped. After the posterior unipedal 

 contact the body is raised from the soil, P, to touch it again and com- 

 plete a half-step. 



M. Lenoble du Teil has calculated that the duration of each foot 

 on the soil lasted about fourteen-hundredths of a second, or three- 

 elevenths of the total duration of the step, while the unipedal contacts, 

 much shorter, equal each only one-ninth of the time of the contact 

 of the feet. One understands then the impossibility of appreciating 

 clearly this analysis of the diagonal beats under such velocity. 



As to the phases of projection, they are equal to two-thirds of the 

 duration of the contact, that is to say, relatively long in relation to 

 what they are in the perfectly synchronous trot. 



In the absence of more numerous data, the preceding facts have 

 only the value of a simple indication, upon which it would, no doubt, 

 be premature to establish the definite theory of the fast trot. Never- 

 theless, they are a step in the course of its mechanism. 



The conclusion which can be deduced from them is that, at certain 

 moments, four times in the same step, the body is supported only by 

 one member. The anterior limbs have individually to sustain the 

 effect of the fall of the body at great speed, while the posterior are 

 likewise by turns severally taxed with the communicating of the im- 

 pulsion. The apparatus of impulsion of the latter and the apparatus 

 of amortissement (dispersion of concussion) of the former are therefore 

 frequently exposed to exertions from which they would be spared were 

 not the synchronism of the diagonal beats more or less destroyed. 

 Hence it is that the habitual employment of the flying trot contributes 

 to the premature ruin. of the fetlocks and the hocks, particularly in 

 young horses. 



But in the broken trot is it always an anterior member which 

 arrives first in contact ? Is it not sometimes a posterior ? It is pos- 

 sible that these two modes of disassociation of the diagonal beats 

 can exist, although science only possesses presumptions upon this 

 point. 



M. Lenoble du Teil l thinks that the hind-feet rest first whenever 

 the diagonal base notably exceeds three-fourths of the height, and the 

 head and neck of the horse, slightly elevated, displace the weight upon 

 the posterior quarters. These conditions of equilibrium are realized 

 when the jockey pulls the horse's head violently with the reins, in 

 mediocre trotters, in young horses which have had no training, and in 



1 Lenoble du Teil, note communique^. 



