176 EXTRACTS FROM NOTE-BOOKS. CH. XXXI. 



on between animals of different kinds, which is as 

 perfectly understood by them as if they could 

 communicate by words. 



It is difficult to determine how far we are right 

 in endeavouring utterly to destroy one kind of 

 animal or bird in order to increase another species. 

 Nature, if left to herself, keeps up a fair equili- 

 brium and proportion amongst all her productions ; 

 and, without doubt, if the world were left to itself 

 without the interference of mankind, there would 

 never be an undue proportion of any one kind of 

 living creature: the birds of prey would keep down 

 the granivorous birds from increasing till they de- 

 voured all the fruits of the earth ; and the carnivo- 

 rous birds and beasts would never entirely extirpate 

 any other species, as their own numbers would be 

 lessened by want of food before this could happen ; 

 besides which, we see that, unless artificial means 

 are resorted to, the number of living animals always 

 bears proportion to, and is regulated by the supply 

 of food which offers itself ; and, as these supplies 

 fail, there is a natural tendency for the consumers 

 to cease increasing, or to betake themselves to 

 other regions. But when man comes in as an 

 active agent, he gradually extirpates all beasts and 

 birds of prey for the purpose of protecting and 

 causing to increase the weaker but more useful 



