206 THE UNIVERSE. 



annihilate them. They have no choice left, and thus 

 forced migrations arise. 



Civilization proceeds in the same manner. Animals dis- 

 appear as it advances. It drives them back, or utterly de- 

 stroys them. Many large species which found shelter in 

 the former forests of Gaul, the aurochs and others, have 

 vanished from our land. We only find now the crumbling 

 bones of these wild mammals which our sturdy forefathers 

 hunted. 



When animals perform their journeys annually we ob- 

 serve an amount of order and foresight which are not seen 

 in erratic migrations. During these latter the whole colony 

 sometimes expires, overcome by the elements or hunger ; 

 not a single individual ever sees again the country which 

 the tribe quitted in innumerable columns. In the former, 

 on the contrary, instructed by an experience from which all 

 profit, the journey is performed with a degree of order that 

 fills us with astonishment. 



The arrangement observed by wild geese in traversing 

 the air, when they are making their way to a distant coun- 

 try, shows that they possess a certain power of mental com- 

 bination. They are placed one behind the other in two 

 long oblique lines, which form an acute angle in front, the 

 most suitable form for cleaving: the air. And as the in- 

 dividual placed at the head of the phalanx exerts himself 

 more than the others to open the path, he is observed, so 

 soon as he finds himself fatigued, to drop behind and take 

 the last place, while another succeeds to his. 



I thought there was perhaps more poetry than truth in 

 what the old naturalists have related on this head, but hav- 



