IV. 



THE STKUGGLE FOE EXISTENCE. 



Origin of -^ STEUGGLB for existence inevitably fol- 



Species, lows from the high rate at which all organic 

 ^*^^ ■ beings tend to increase. Every being, which 

 during its natural lifetime produces several eggs or seeds, 

 must suffer destruction during some period of its life, 

 and during some season or occasional year, otherwise, on 

 the principle of geometrical increase, its numbers would 

 quickly become so inordinately great that no country 

 could support the product. Hence, as more individuals 

 are produced than can possibly survive, there must in 

 every case be a struggle for existence, either one indi- 

 vidual with another of the same species, or with the in- 

 dividuals of distinct species, or with the physical condi- 

 tions of life. It is the doctrine of Malthus applied with 

 manifold force to the whole animal and vegetable king- 

 doms ; for in this case there can be no artificial increase 

 of food, and no prudential restraint from marriage. Al- 

 though some species may be now increasing, more or less 

 rapidly, in numbers, all can not do so, for the world 

 would not hold them. 



There is no exception to the rule that every organic 

 being naturally increases at so high a rate, that, if not 

 destroyed, the earth would soon be covered with the 

 5 



