82 NATURAL HISTORY OF 



rous animals, without a natural check, would soon 

 become too numerous for the substances which nave 

 been allotted for their nourishment, and, by creating 

 famine, would be the cause of their own destruction. 

 Instances of such a sweep upon the vegetation of a 

 country, have in reality occurred. A recent travel- 

 ler in South Africa, thus writes of the migrations of 

 the Trek-boken or Migratory Springboks * : " It 

 is scarcely possible for a person passing over some 

 of the extensive tracts of the interior, and admiring 

 that elegant antelope, the Springbok, thinly scatter- 

 ed over the plains, and bounding in playful inno- 

 cence, to figure to himself that these ornaments of 

 the desert can often become as destructive as the lo- 

 custs themselves. The incredible number which 

 sometimes pour in from the north, during protracted 

 droughts, distress the farmer inconceivably. Any 

 attempt at numerical computation would be vain ; 

 and by trying to come near the truth, the writer 

 would subject himself, in the eyes of those who have 

 no knowledge of the country, to a suspicion that he 

 was availing himself of a traveller's assumed privi- 

 lege ; yet it is we known in the interior, that, on 

 the approach of the Trek-boken, the grazier makes 

 up his mind to look for pasturage for his flocks else- 

 where, and considers himself entirely dispossessed wf 



* The same writer computes the number of 

 in the Karroo Plains, een within a compass of fifty miles, 

 to be at least 100,000. 



