178 THE SCIENCE OF BIOLOGY 



ian theory as the cause of evolution, a fact which probably 

 rendered his views on the broader question of descent 

 less palatable to his countrymen. In his later writings, 

 Spencer was primarily a philosopher, and this may account 

 in part for the scant acknowledgment he has been given by 

 scientists as compared with Darwin. Nevertheless he occu- 

 pies an important place in any critical history of the doc- 

 trine of evolution, because of his early conviction that such a 

 theory was the only reasonable interpretation which could be 

 placed upon the facts, as well as on account of his thoroughly 

 scientific viewpoint. 



The foregoing discussion serves as an introduction to the 

 work of Charles Darwin (1809-1882). Darwin deserves 

 the place he occupies, because he combined the grasp of the 

 philosopher with the accuracy of the scientist. While still 

 a young man^on the Voyage of the Beagle (1831-1836), he 

 perceived the significance of biological and geological phe- 

 nomena which he later used as evidence for organic evolution. 

 So impressed was he by what he had seen, in parts of the 

 world where nature had been little changed by man, that 

 after his return he began the studies which culminated 

 twenty years later in his "Origin of Species" (1859). The 

 simultaneous announcement by Darwin and Wallace, of 

 the theory of Natural Selection is a familiar story. 21 In the 

 summer of 1858, Darwin received a letter from his fellow 

 naturalist, Alfred Russel Wallace, who was then in the Malay 

 archipelago, asking Darwin to present on his behalf a theory 

 of the origin of species that Wallace had outlined. The 

 conclusions set forth in this brief communication were 



change of circumstances, ten millions of varieties have been produced, as 

 varieties are being produced still?" 



21 The two brief papers were published in the Journal of the Proceeding of 

 the Linnean Society, 1858, p. 45. Apparently, they made little impression, for 

 Darwin tells us in his autobiography that the only published notice he remem- 

 bered was to the effect "that all that was new in them was false and what was 

 true was old." Reprints of these papers will be found in the Popular Science 

 Monthly, Nov., 1901. 



