316 THE HORSE AND HIS STRUCTURE. 



and afford a better leverage. Passing over this bone, as 

 is seen in the section, the tendon is attached to the sole 

 of the coffin bone, so as to bend the joint when the muscle 

 to which it belongs is contracted. 



The projection T, which is so conspicuous in the 

 pastern, is due to a fatty cushion, the object of which 

 is very uncertain. 



Now we will take the protective covering of this 

 mechanism, and see how on the exterior it is hard 

 enough to bear the weight of the horse even upon rocky 

 or stony ground, while it is so soft within that it can be 

 furnished with arteries, sinews, and nerves. The horny 

 outside of the hoof is called the "crust" (R in the sec- 

 tion), and is so formed that as it is worn away below, 

 under ordinary circumstances, the growth and waste 

 exactly counterbalance each other. 



