78 LEAVES FROM THE BOOK OF NATURE. 



of prey, to seek new pastures and new dwelling-places. 

 Others, again, follow man in his migrations over the globe, 

 and thus spread from country to country. To the former, 

 belong the horses which now roam wild on the plains of 

 South America, and travel, at times, thousands of miles. 

 The wild asses, also, in the wilderness, " which Stand up 

 in the high places and snuff the wind like dragons," travel 

 in bands of two or three hundred, and leave, in winter, 

 the tropics for a still warmer region in the south of 

 Africa. They are called "the Bushman's harvest," for the 

 wild Bushman hunts and consumes what has been left by 

 the royal lion and the hungry vulture, who follow them 

 in their march and feast upon them for a season. Ga- 

 zelles and antelopes migrate in like manner, and even 

 huge elephants are seen wandering in large herds over 

 the boundless plains of Africa. The shaggy buffalo roams 

 in vast numbers over the prairies of our own continent, 

 and migrates at regular intervals from the north to the 

 south, and from the plain to the mountain. Salt springs 

 are with them the great centre of attraction, but gen- 

 erally their movements seem to be regulated by the state 

 of their pastures. As soon as the fire has spread over 

 a prairie, and is succeeded by a fine growth of tender 

 grass, immense herds are sure to appear. How they dis- 

 cover that their table is spread, we know not ; it has 

 been surmised that stragglers from the main body, who 

 have wandered away when food became scarce, may first 

 notice the new growth, and by some mysterious means, 

 communicate the good news to their hungry brethren. 

 Monkeys, also, wander from land to land, when driven 



