THE SKELETON. 27 



man it rests upon the spine, nicely balanced, as on a pivot ; but 

 the larger heads of quadrupeds are suspended from the bod v. 

 Now if we consider the immense weight of the head of the horse, 

 Avhich is much increased from being placed at the extremity of 

 a lever, we cannot fail to be convinced of the prodigious power 

 necessary to support it. If this weight were supported by mus- 

 cular power, there would be a very considerable consumption of 

 vital energy ; but to save the exhaustion this would produce, 

 there is a large ligament rising from the occiput, attached to the 

 bones of the neck and the spines of the back, which, being 

 elastic, admits the motions of the head, and sujiports it at all 

 times, even when the muscles are in a doi'mant state. This 

 ligament is known as the ligamentum colli, or, commonly, as the 

 pack wax. 



We must now proceed to describe the spine and chest. The 

 spinal column has three important offices to perform : it is the 

 great bond of union between all parts of the body ; it forms a tube 

 for the passage of the spinal marrow, a part as important as the 

 brain itself; and, lastly, it is in animals the fixed object from 

 whence the head is suspended. If the protection of the spinal 

 marrow were the only object to be effected, it would have been 

 simply a strong bony tube : but whilst it possesses great strength 

 for this purpose, considerable flexibility is also required, and 

 accordingly it is composed of a multitude of bones, more or less 

 in different animals, accordlnfr to their wants and habits. The 

 feline races require the utmost degree of elasticity, in order to 

 climb up and spring from eminences, and seize their prey with 

 facility ; but if these animals could be tamed sufficiently to make 

 them bear burdens or go in harness, they could render us but 

 little service in this new capacity, from the want of strength and 

 stability in the spinal column. But in herbivorous animals, 

 which are required to draw or sustain heavy weights, strength is 

 the principal object, and accordingly we find they have much 

 less flexibility than cai'uivorous animals : this stability is the 

 distinguishing feature of the whole skeleton, but more parti- 

 cularly of the spinal colunm, of the horse. 



The Nt'ch of the horse is composed of seven bones, the two 

 first of which will more particularly demand our attention, as 

 they differ essentially from the others in their aspect and their 

 use. The first is called the atlas, from the circumstance of its 

 sustaining the head, as it does in man, although in the horse the 

 head is rather suspended from it. The second is called the 

 dentata, from having a tooth-like process on its front part. 

 The atlas has concavities on its anterior part, which ai'ticulate 

 with two smooth condyles or pi'ominences on the occipital, the 

 last bone of the skull ; this joint is called into requisition in 

 bending the head backwards and forwards, and particularly in 



