284 'THE EXTERIOR OF THE HORSE. 



in order to duly sustain the body-weight, particularly in the anterior 

 members, in view of their function and their closer situation to the 

 centre of gravity. The least displacement forward, backward, out- 

 ward, or inward makes the horse appear deficient in the axes ; its 

 articulations in certain regions are surcharged ; their constituent parts 

 and the ligaments which unite them show signs, in the long run, of 

 the concussions, of the violent tractions, a necessary consequence of 

 the mode of superposition of the locomotory segments. Finally, the 

 muscles themselves, supposing that the articulations are sound, are 

 oblio-ed to display more force in order to maintain the bones in a good 

 direction, which in normal conditions claim but little of their co-opera- 

 tion to preserve their equilibrium. The deviations of the canon are 

 less prejudicial to the integrity of the locomotory apparatus when they 

 are confined only to the posterior members; the animal is not less 

 defective for this reason ; only the eifects of these alterations are 

 slower in manifesting themselves. We will return to all these facta 

 when we discuss the direction of the axes. 



Length. — ^The absolute length of the canon merits to be taken 

 into consideration in the case of rapid motors. It has not much im- 

 portance in the draught-horse. 



In well-formed subjects, whatever may be the race to which they 

 belong, the metatarsus is always longer than the metacarpus. We will 

 say that, all things being equal, the latter are constantly longer in 

 animals of speed, when compared in this relation to those of the 

 draught-horse. With equality of form, the canon of the draught- 

 horse is shorter than that of the thoroughbred; the body of the 

 former is nearer to the ground and more voluminous than that of the 

 latter, which, to use the comparison, appears, to a certain degree, 

 mounted on stilts. It is easy to verify this statement by measure- 

 ments which we ourselves have been careful to make before abandoning 

 the classical opinion which claims that race-horses have their hocks as 

 low as possible. We see, then, all proportions being of course consid- 

 ered, that their canons are always longer than is believed. Hence 

 these animals possess more speed, for necessarily they embrace at each 

 step a longer expanse of space. 



The relative length of the canon should be studied with regard to 

 the region which surmounts it, the leg or the forearm. 



We know already that the length of the broken radio-metacarpal 

 or tibio-metatarsal lever in rapid motors is due to the development of 

 the superior bone, the radius or the tibia. It is necessary, therefore, 

 that the canon be in such cases short. When it is thus, we know that 



