332 THE HOBSE AOT) HIS STETJCTHRE. 



hold its head up without fatigue. We could not do it, 

 and if we were placed on all fours, we should soon find 

 our heads drooping from sheer fatigue. 



If we place a hand on the back of our neck and bend 

 the head forward, we shall feel a strong ligament. If 

 the skin be removed, this ligament is seen to be cord- 

 like, and not to present any very remarkable peculiarity 

 of structure. 



In the horse, however, it is developed into a most 

 wonderful elastic mechanism. Lapping over the back of 

 the neck, as shown in the illustration at A, it throws out 

 a set of projections, each of which is fastened to one of 

 the vertebrae of the neck in such a manner that, while it 

 gives support to that particular vertebra, it works simul- 

 taneously with the others. 



Thus, the animal can toss or shake its head, turn it 

 round to its flanks, or depress it to its knees, the power- 

 ful and highly -elastic ligaments permitting all these 

 movements, and by their own resilience restoring the 

 head and neck to their normal position when the muscles 

 are relaxed. 



The weight of the head and neck is very considerable, 

 and by their movements the balance of the body is mate- 

 rially aided, e.g., in walking up a very steep hill, the horse 

 when at liberty throws his head and neck well forward, 

 so as to keep the weight as much as possible in front of the 

 fore-feet. In descending the same hill, the horse holds 

 his head and neck as far back as he can, so as to throw 

 the weight behind the fore-feet. 



