102 THE EXTERIOR OF THE HORSE. 



fatigued. " If the last," says H. Bouley, 1 " are prevented, by the 

 resistance of the reins, from inclining the head towards the ground, 

 they continually toss it up and down, and by this oscillating move- 

 ment ease the muscles and relieve themselves of the fatigue which this 

 position occasions." We also see horses that are attached to heavy 

 loads assume this attitude occasionally, for reasons which we have seen 

 when speaking of the direction of the head. 



Whatever may be the circumstances under which we observe it, the 

 animal always has a hard mouth, and his gait is shortened. We must 

 except, here, the race-horse, whose neck is held horizontally when he is 

 urged to his utmost speed, but assumes another position under ordinary 

 circumstances. All these facts are explained by the mechanical consid- 

 erations employed above. 



Let, for example, mn and OC be the relative direction of the 

 shoulder and the neck (Fig. 32). It is plain that the mastoido-hume- 

 ralis is shortened, and therefore has a limited degree of contraction. 

 Nevertheless, its insertion in the shoulder is much more perpendicular 

 than in the preceding direction, whence it results that the muscle will 

 be more powerful as regards the intensity of its action. We understand 

 from this fact how it is that horses which become exhausted during 

 a long journey carry the neck in this direction. Moreover, the line 

 of gravitation, CR, of the head tends to become more and more per- 

 pendicular with the cervical axis, which gives to the head a greater 

 power of resistance and explains why these animals are always hard- 

 mouthed. 



The head thus held displaces, besides, the centre of gravity forward, 

 relieves the posterior extremity of the body from a portion of the weight 

 sustained by it, and exacts a smaller expenditure of force in the propul- 

 sive efforts of the hind limbs. 



3d. Finally, the neck may assume an intermediate direction, that is 

 to say, an obliquity of about 45 degrees. We see again, by inspecting 

 Fig. 32, that in this instance the advantages and disadvantages of the 

 two preceding directions are about equally distributed. The muscles 

 have a mean length, and their incidence with the shoulder is favorable, 

 the step is sufficiently extended, and the head is neither too light nor 

 too heavy on the rein. In a word, for good service, this is the usual 

 position assumed by most horses, the golden mean to which it should 

 be reduced. 



Volume. The volume of the neck should not be too large. 



1 H. Bouley, Dictionnaire pratique de mdecine, de chirurgie et d'hygiene veterinaires, t. 

 vi. art. " Encolure." 



