314 THE UNIVERSE. 



nature. But this very fecundity is fatal to the weak tribes, 

 the stronger ones, getting the u2Dper hand, drive them away 

 or annihilate them. They have no choice left and thus 

 forced migrations arise. 



Civilization proceeds in the same manner. Animals 

 disai^pear as it advances. It drives them back, or utterly 

 destroys them. IMany large species which found shelter 

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

 vanished fr6m 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 amoimt of order and foresight which are not 

 seen in erratic migrations. Dimng 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, Avhen they are making their way to a distant coun- 

 try, sliows that they possess a certain power of mental 

 comljination. They are placed one liehind the other in 

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

 the most suital)le form for cleaving the air. And as the 

 individual placed at the head of the phalanx exerts him- 

 self 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 natiu-alists have related on this head, but 

 having, on the banks of the Nile, frequently seen flocks of 



