On Certain Factors of Evolution. 819 
first rank, it is noteworthy that he sees clearly that natural selection 
is not the sole factor in organic evolution, as will be seen by the 
general drift of his essays, by his quoting with approval Huxley’s 
significant remark that “Science commits suicide when it adopts a 
creed,” and by the following extracts from his own essays :— 
“But now, recognizing in full this process brought into clear 
view by Mr. Darwin, and traced out by him with so much care 
and skill, can we conclude that, taken alone, it accounts for organic 
evolution? Has the natural selection of favorable variations been 
the sole factor? On critically examining the evidence we shall 
find reason to think that it by no means explains all that has to be 
explained” (p. 9), 
During that earlier period, when he was discovering the multitu- 
dinous cases in which his own hypothesis afforded solutions, and 
simultaneously observing how utterly futile in these multitudinous 
cases was the hypothesis propounded by his grandfather and 
Lamarck, Mr. Darwin was, not unnaturally, almost betrayed into 
the belief that the one is all-sufficient and the other inoperative.! 
But in the mind of one usually so candid and ever open to more 
evidence there naturally came a reaction. The inheritance of 
functionally produced modifications, which, judging by the passage 
quoted above concerning the views of these earlier inquirers, would 
seem to have been at one time denied, but which, as we have seen, 
was always to some extent recognized, came to be recognized more 
and more, and deliberately included as a factor of importance. 
In his references to the works and opinions of other naturalists 
Mr. Spencer confines himself almost exclusively to those of Mr. 
Darwin, who always opposed, and, it must be confessed, with less 
than his usual candor and fairness, the views of Lamarck as to the 
influence of a change in the environment upon organisms.” 
It seems singular that Mr. Spencer should not be acquainted 
1 It is surprising to read in Darwin’s Life, by his son, the expressions 
showing his lack of appreciation of Lamarck and his work; Darwin seems 
m the first to have been strongly prejudiced against Lamarck’s 
views, and never to have done them justice. 
* In the Origin of Species (p. xiv., note) Darwin writes, as quoted by 
Spencer: “It is curious how largely my grandfather, Dr. Erasmus 
Darwin, anticipated the views and erroneous grounds of opinion of 
ago tg in his ‘Zoonomia’ (vol. i., pp. 500-510), published in 1794” 
p. Je 
