306 



THE EXTERIOR OF THE HORSE. 



Therefore the straight joint surcharges the bones and relieves the 

 muscles AM, which antagonize the force Oe, while the long joint favors 

 the bones at the expense of the tendons which it exhausts. 



The pastern plays a no less important part as a lever, whatever way 

 we examine it. 



Being still given the two pasterns OB and OD (Fig. 104), of the same 

 length, but unequally inclined upon the canon OC: They form with the great 



FIG. 104. 



FIG. 105. 



sesamoids, A, two angular levers, A OB and AOD, of the second class, whose 

 point of contact or fulcrum is on the ground at B and D, whose resistance, R, 

 is at 0, and whose power, M, is at A. 



It is apparent that by drawing the perpendiculars BF and DE from the 

 points of contact upon the direction of the force R, that is to say, the arms of 

 the lever of resistance for each of these inclinations, this force will act at the 

 extremity of an arm longer in the case of the low-jointed pastern than in that 

 of the straight-jointed one. 



The obliquity of the phalangal lever, therefore, obliges the mus- 

 cles AM, whose lever-arm remains invariable, to make more energetic 



