Geological Work in Old Age 379 
elucidation of many of the difficulties that presented themselves. 
I well remember a visit which I paid to Down at this period. At the 
side of the little study stood flower-pots containing earth with worms, 
and, without interrupting our conversation, Darwin would from time 
to time lift the glass plate covering a pot to watch what was going 
on. Occasionally, with a humourous smile, he would murmur some- 
thing about a book in another room, and slip. away; returning 
shortly, without the book but. with unmistakeable signs of having 
visited the snuff-jar- outside. After working about a year at the 
worms, he was able at the end of 1881 to publish the charming little 
book—The Formation of Vegetable Mould through the Action of 
Worms, with Observations on their Habits. This was the last of his 
books, and its reception by reviewers and the public alike afforded 
the patient old worker no little gratification. Darwin’s scientific 
career, which had begun with geological research, most appropriately 
ended with a return to it. 
It has been impossible to sketch the origin and influence of 
Darwin’s geological work without, at almost every step, referring to 
the part played by Lyell and the Principles of Geology. Haeckel, 
in the chapters on Lyell and Darwin in his History of Creation, and 
Huxley in his striking essay On the Reception of the Origin of 
Species! have both strongly insisted on the fact that the Origin of 
Darwin was a necessary corollary to the Principles of Lyell. 
It is true that,:in an earlier essay, Huxley had spoken of the 
doctrine of Uniformitarianism as being, in a certain sense, opposed 
to that of Evolution’; but in his later years he took up a very 
different and more logical position, and maintained that “ Consistent 
uniformitarianism postulates evolution as much in the organic as in 
the inorganic world. The origin of a new species by other than 
ordinary agencies would be a vastly greater ‘catastrophe’ than any 
of those which Lyell successfully eliminated from sober geological 
speculation®.” 
Huxley’s admiration for the Principles of Geology, and his con- 
viction of the greatness of the revolution of thought brought about 
by Lyell, was almost as marked as in the case of Darwin himself*. He 
felt, however, as many others have done, that in one respect the 
very success of Lyell’s masterpiece has been the reason why its 
originality and influence have not been so fully recognised as they 
deserved to be. Written as the book was before its author had 
11, L, a. pp. 179—204. 
® Huzley’s Address to the Geological Society, 1869. Collected Essays, Vol. vu. p. 305, 
London, 1896. 
3 L. L. 1. p. 190. 
4 See his Essay on ‘Science and Pseudo Science.” Collected Essays, Vol. v. p. 90, 
London, 1902. 
