342 THE MECHANICAL FUNCTIONS. 



too-ether a short time before the others have reached the 

 ground: so that during that minute interval of time all the 

 feet are in the air at the same moment; and during the re- 

 maining portion of the time, the body is resting upon the 

 two feet placed diagonally with regard to each other. The 

 undulations are here chiefly vertical, instead of lateral, as 

 they are in the walking pace. 



A gallop is a continued succession of longer leaps made 

 by the two hind feet in conjunction. In this case, the cen- 

 tre of gravity is lifted higher from the ground, and is pro- 

 jected in a wide arch, and with great velojcity. 



In the amble, both the legs on one side are raised toge- 

 ther; so that the impulsions given are directed much more 

 laterally than in any other pace, and the body is thrown into 

 a strong undulatory motion from side to side: 



Another kind of pace is the bound, which is often prac- 

 tised by deer, and is performed by striking the ground with 

 all the legs at the same moment. It consists, therefore, like 

 the gallop, of a series of leaps; but their direction is more 

 uniformly upwards, from the concurrence of all the legs in 

 the same action. 



Nature has purposely endowed different tribes with very 

 different capacities to execute progressive movements, by 

 the variations she has introduced into the comparative 

 lengths of the several parts of the trunk, and the size and 

 mobility of the extremities. Of all the large animals, the 

 Lion has been constructed with the finest proportions for 

 conferring both strength and activity. The mass of his 

 body is supported more by the fore than by the hind ex- 

 tremities. In walking, the lion takes long strides, and ex- 

 hibits strongly the lateral undulations of the trunk. 



Quadrupeds having a very long, or a very massive body, 

 or whose limbs are short, and nearly of equal height, are in- 

 capable of advancing by a gallop, or at least cannot sustain 

 this pace without a painful effort, and never but for a short 

 time. The Tiger, which has a longer body than the lion, 

 gallops with less facility; and runs chiefly by an accelera- 

 tion of its walking pace. It excels principally in the vigour 



