BOOK VII 



THE MIGEATIONS OF ANIMALS. 



Many animals, carried away by imperions demands, or 

 hj an instinctive irresistible force, qnit their habitual resid- 

 ence at a given moment, and direct their way to distant 

 regions. Such migrations, the object of which eludes our 

 oliservation, are noticed in nearly all classes of the animal 

 kingdom. Usually they are seen to take place periodically^ 

 but at other times they only occur, as it were, accidentally, 

 and all at once astonish the inhabitants of the countries 

 which are the theatre of them, and into which the unex- 

 pected invaders carry sometimes devastation, famine, and 

 death. 



At other times it is violence that compels legions of 

 animals to cjuit the place Avliere they had established them- 

 selves. In the countries where man does not decimate 

 them, they swarm in such abundance, and are so crowded 

 together, that one can scarcely understand how they exist; 

 their numbers are alarming. The pictures that Livingstone 

 has drawn of the exuberance of game in wild districts of 

 Central Africa, and in particular on the banks of the 

 Zambesi, suffice to give us an idea of the fecundity of 



