Balance of Species. \ \ 7 



We shall incidentally, in other connections, point 

 out many of nature's plans for the preservation of 

 species. Instinct brings the bee to fertilize the 

 flower, that but for her would fail to produce seed, 

 so that in time the species would become extinct. 

 The tree provides for its young by a law of its own 

 growth, and the animal by instinct makes provision 

 for its young wherever peculiar c< mditions are needed 

 for their preservation. The vegetable kingdom 

 sometimes supplements that instinct, and provides 

 by special growth both food and home for the in 

 young. So perfectly are all these means adjusted, 

 that, so far as we know, no animal or plant has be- 

 come extinct in modern times except through the 

 ncy of man. 



But it is not enough that the species should be 

 piv there must also be a balance of species. 



Too great a preponderance of one kind would be 

 attended by injury or destruction of others. The 

 number of each species must be determined by its 

 relations to other organic beings. Carnivorous ani- 

 mals cannot be more numerous than herbivorous. 

 Birds of prey must be few in number compared with 

 those upon which they feed. There is thus a cer- 

 tain limit fixed to the relative number of different 

 animals, by the amount of food fitted to sustain each 

 kind, and by the climate which they can endure. 

 But nature has not left all to push on to the utmost 

 bounds of possible existence. She has plainly set 

 limits to the power of increase among the great de- 

 stroyers of animal life, that the species which she 



