PRINCIPLE OF NATURAL SELECTION. 2IQ 



ciple of Population," which fell into Darwin's 

 hands. The purpose of Malthus in this work 

 was to investigate the causes that had hitherto 

 impeded the progress of mankind toward hap- 

 piness. After establishing the principle that 

 population has a tendency to increase in geo- 

 metrical ratio, while the food supply can at best 

 increase only in arithmetical ratio, he pointed 

 out that the ultimate check to the increase of 

 population is lack of food; and that all the 

 immediate checks could be included under three 

 heads, moral restraint, vice, and misery, and 

 urged moral restraint as a check to population, 

 because by it alone could vice and misery be 

 driven out of the world. 1 



Malthus stated with perfect clearness "the 

 constant tendency in all animated life to in- 

 crease beyond the nourishment prepared for 

 it," and the consequent struggle for existence; 

 and insisted that in every country, speaking of 

 the human family, some of the checks to popu- 

 lation are, with more or less force, in constant 

 operation. 2 He recognized both artificial and 

 natural selection as results of the struggle for 

 existence. In the chapter on the " Checks to 

 Population among the American Indians," he 

 said: 



1 Malthus, Principle of Population (gth edition), pp. 1-8. 



2 Ibid., p. 9. 



