Chapter V 

 Malthusianism and the Law of Population 



WE have proved that in all prolific herbivora and 

 carnivora the checks upon increase of popula- 

 tion are known positively. We must now go a little 

 further and ask if there are any checks to the excess 

 of reproduction in the case of the " genus homo 

 sapiens." 



We must recall again Darwin's words in defining his 

 struggle for existence : " Hence, as more individuals 

 are produced than can possibly survive, there must, 

 in every case, be a struggle for existence, either one 

 individual with another of the same species or with the 

 individuals of distinct species, or with the physical 

 conditions of life. It is the doctrine of Malthus applied 

 with manifold force to the whole animal and vegetable 

 kingdom ; for in this case there can be no artificial 

 increase of food and no prudential restraint from 

 marriage. . . . The causes which check the natural 

 tendency of each species to increase are most obscure. 

 Look at the most vigorous species : by as much as it 

 swarms in numbers, by so much will it tend to increase 

 still further. We know not exactly what the checks 

 are, even in a single instance." 



As we have shown in a former chapter, we know 

 positively the checks in the prolific species, and that 

 they act automatically and without internecine strife, 

 and that necessarily the theory of natural selection 

 can be supported no longer. But we must now consider 

 how the prolific " genus homo sapiens " is affected 

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