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 (1809-1882) 
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.2 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 
1 Packard, Lamarck, p. 331. 2 Ibid., pp. 230 f. 
