58 ADAPTATION AND PROGRESS 



fied their structure, they enjoy more or less freedom of the will, 

 can choose, and can vary their acts, or at least some of them.'' ^ 

 That is, if man's mode of existence calls for stronger muscles in 

 any part of his body, he can, by taking thought, exercise and thus 

 develop those parts. In this sense the organism is modified by a 

 consciousness of need and an act of will, although the process of 

 adaptation is in strict accordance with law. 



Charles Darwin (i 809-1 882) 

 Natural Selection 



Charles Darwin was born at Shrewsbury, England, of an an- 

 cestry that by " nature " or " nurture " had much to do with his 

 future life-work. His grandfather, Erasmus, in his Zoonomia 

 published in 1794, had laid down ten principles bearing on evolu- 

 tion, many of which became famous later through Lamarck and 

 Charles Darwin, though they were worked out independently by 

 the former and to a considerable extent by the latter.^ His 

 father Robert was a most acute observer of nature. From him 

 came caution and conservatism. It is significant, too, that his 

 cousin was the Francis Galton who was the founder of the science 

 of eugenics. 



In formal education Darwin was not a success. Turning aside 

 from medicine which he studied at Edinburgh, and from the- 

 ology which he studied at Cambridge, he closed his academic 

 studies with his chief asset the scientific inspiration which he 

 received from the botanist Professor Henslow, and the geologist. 

 Professor Sedgwick. The two books to which he was most 

 indebted were Lyell's Principles of Geology and Malthus on 

 Population, — the two books which profoundly influenced 

 Spencer also. The most potent factor in Darwin's education, 

 apart from the influence of these teachers, was the experience he 

 had as naturalist on the "Beagle" which made a tour of the 

 world for scientific purposes in 1831-36. 



With broken health, his great work. The Origin of Species, was 

 published in 1859 after twenty-one years of labor to demonstrate 

 ^ Packard, Lamarck j p. 331. ^ Ibid., pp. 230 f. 



