THE STRUGGLE FOR EXISTENCE 57 



the gaps that have been made in the numbers of the 

 species are quickly filled up. Hence it is evident 

 that the several kinds of destruction which Darwin 

 took pains to enumerate are not in reality checks 

 upon the increase of species imposed by Nature, but 

 are mere temporary calamities : for the individuals 

 destroyed by them leave their place vacant to afford 

 ampler room for the females to hide and bring forth 

 in safety. It will now be seen that Nature had a 

 great economic end in view, when she endowed her 

 species with so great a power of procreation ; and also 

 that for all her species she employs but one check which 

 is sufficient for her purpose, while she has provided 

 along with it a principle of recuperation which renders 

 all casualties that occur from time to time powerless 

 to prevent the species from being maintained in their 

 due numbers from generation to generation. 



Nature's check is not the same for all species. 

 She has one check for man, another for unprolific 

 herbivorous animals, which form the food of the 

 carnivora, another for the carnivora and prolific 

 herbivora, another for raptorial birds, and doubtless 

 other kinds of check for other forms of life which we 

 have not considered. 



The destruction of the spawn and small fry by the 

 adult fishes, and of smaller by larger kinds, I take to 

 be Nature's mode of eliminating the excess of reproduc- 

 tion in this domain of animal life. We have here no 

 concealment of the females, or special instinct on the 

 part of the males ; for the females take as active a 



