428 



BIOLOGY AXD ITS MAKERS 



checks' described by Malthus in his Essay on Population, 

 a work I had read several years before, and which had made 



* 



a deep and permanent impression on my mind. These 

 checks war, disease, famine, and the like must, it occurred 

 to me, act on animals as well as man. Then I thought of 



FIG. 120. ALFRED RUSSEL WALLACE, BORN 1823. 



the enormously rapid multiplication of animals, causing these 

 checks to be much more effective in them than in the case of 

 man; and while pondering vaguely on this fact, there sud- 

 denly flashed upon me the idea of the survival of the fittest- 

 that the individuals removed bv these checks must be on the 



