48 FORM AND ACTION. 



of the scapula, in which its base turns backward and downward, 

 its apex forward and upward, and in a simultaneous flexion and 

 elevation of the humerus, the effect of which is to diminish the 

 distance (represented in Fig. IV by the dotted line e) between it 

 and the scapula. The projection of the limb in front of the body 

 is effected by an extension of the humerus on the scapula, and, 

 in rapid or forced movements, by an advance (not a revolution) of 

 the scapula as well: but the instant the foot is grounded and 

 becomes a fixed point and fulcrum, the scapula commences a 

 counter-revolution, its base moving forward and upward, its apex 

 backward and downward, and the humerus returns to its original 

 semi-flexed position. Whether the limb moves upon the body, the 

 foot being off the ground, or the body moves upon the limb, the 

 foot being on the ground, in either case the scapula is in motion, 

 its revolution, in regard to its summit, being backward and down- 

 ward in one case, forward and upward in the other. 



The length, as well as the obliquity, of the scapula will have 

 an influence on the action of the shoulder, it being manifest that a 

 body revolving upon its own centre must describe arcs or sweeps 

 great in proportion to its length ; hence the value of a deep 

 shoulder : though, as regards the scapula itself, the muscles at- 

 tached to and moving it will necessarily be short in a case where 

 the bone is disproportionately long, and vice versa. When the 

 scapula is placed nearly upright, or is of disproportionate short- 

 ness, there cannot be that extent or freedom of action in the 

 shoulders; neither can there be that projecture of the limb that 

 there is in opposite conformations. The movements of the fore 

 limbs are likely to be confined or imperfectly effected, and where 

 those of the hind limbs happen to be " good," or of a more perfect 

 kind — as is not infrequently the case — there will be great danger 

 of the horse being, by the comparatively superior action in the 

 agents of progression, precipitated forwards. 



A good shoulder not only possesses depth and obliquity, but, 

 to complete its perfection, " lie well into the body." How often 

 do we discover upon the superficies of the shoulder a rising a little 

 below and behind the withers, marking the situation of the sum- 

 mit or base of the scapula. In the generality of instances this 

 arises from the ribs being arched in that part, which precludes the 



