SLANTING DIRECTION OP THU SHOULDER. 327 



each other. This will be more evident from the following cut, which represents 

 the fore and hind extremities in the situations which they occupy in the horse. 



This angular construction of the limbs reminds us of the similar arrangement 

 of the springs of a carriage, and the ease of motion, and almost perfect freedom 

 from jolting, which are thereby obtained. 



It must not perhaps be said, that the form of the spring was borrowed from 

 this construction of the limbs of the horse, but the effect of the carriage-spring 

 beautifully illustrates the connexion of the different bones in the extremities of 

 this quadruped. 



The obliquity or slanting direction of the shoulder effects other very useful 

 purposes. That the stride in the gallop, or the space passed over in the trot, 

 may be extensive, it is necessary that the fore part of the animal should be con- 

 siderably elevated. The shoulder, by means of the muscles which extend from 

 it to the inferior part of the limb, is the grand agent in effecting this. Had 

 the bones of the shoulder been placed more upright than we see them, they 

 could not then have been of the length which they now are, — their connexion 

 with the chest could not have been so secure, — and their movements upon each 

 other would have been comparatively restricted. The slightest inspection of 

 this cut, or of that at page 108, will show that, just in proportion as the point 

 of the shoulder is brought forward and elevated, will be the forward action and 

 elevation of the limb, or the space passed over at every effort. 



The slanting shoulder accomplishes a most useful object. The muscles 

 extending from the shoulder-blade to the lower bone of the shoulder are the 

 powers by which motion is given to the whole of the limb. The extent and 

 energy of that motion depend much on the force exerted or the strength of the 

 muscle, but there are circumstances in the relative situations of the different 

 bones which have far greater influence. 



Let it be supposed that, by menus of a lever, some one is endeavouring to 

 raise a certain weight. 



