500 THE MECHANICAL FUNCTIONS. 



which feed principally on herbage. Wherever 

 the earth is cloathed with vegetation, it requires 

 neither skill nor exertion on their part to seek 

 and to devour the rich repast which is profusely 

 spread under their feet. To remove from one 

 pasture to another, to browse, and to repose, con- 

 stitute the peaceful employments of their lives, 

 and satisfy the chief conditions of their existence. 

 To these purposes the whole conformation of their 

 skeleton, and especially of those parts which con- 

 stitute the limbs, is adapted. The anterior ex- 

 tremities having only to support the weight of 

 the fore part of the trunk, and to assist in pro- 

 gressive motion, have a less complicated arrange- 

 ment of joints, and exhibit many of those conso- 

 lidations of the bones, which tend to simplify the 

 structure, and to contribute to its strength. 



But though never incited by the calls of appe- 

 tite to engage' in sanguinary warfare, they are 

 yet liable to the assaults of many ferocious and 

 well armed adversaries, and often improvided 

 with any adequate means of defence ; their only 

 resource, therefore, is to avoid the dangers of 

 the encounter by a rapid and precipitate flight. 

 To confer this power appears to have been the 

 object aimed at by nature in every part of the 

 conformation of these animals. It is among the 

 ruminant tribes that the fleetest of quadrupeds 

 are to be found, such as the gazelle, the ante- 

 lope, and the deer, animals which exhibit the 



