THE DARWIN-WALLACE ESSAY 195 



years before, and the idea of Natural Selection instantly 

 flashed across his mind. But he did not wait for twenty 

 years of thought for repeated observation and experi- 

 mental test. In two hours of ague he had thought out 

 almost the whole of the theory, in three evenings he 

 had completed his account, and it was posted to Darwin 

 by the next mail. 



Thus on July ist, 1858, when Darwin was nearly fifty, 

 and Huxley just over thirty-three, the great theory was 

 before the world ; and the striking thing about the relation 

 of the younger man to this crisis in the history of science, 

 is that he knew really nothing about it. Darwin and 

 Huxley had corresponded for some years prior to 1858 ; 

 but even had this not been so, Darwin was a great 

 central power in biological science, and his writings would 

 naturally be received with the widest Interest. Huxley 

 did not become a Fellow of the Linnean Society until 

 December, 1858, but the publications of scientific societies 

 are readily accessible to all. Huxley certainly knew that 

 Wallace had in some way acted as a stimulus to Darwin ; 

 for he wrote to Hooker on September 5, 1858, ' Wallace's 

 impetus seems to have set Darwin going in earnest, 

 and I am rejoiced to hear we shall learn his views in 

 full, at last. I look forward to a great revolution being 

 effected.'^ But Huxley clearly knew nothing of the 

 contents of the joint memoir; for on June 25, 1859, 

 almost exactly a year after it had appeared, he wrote to 

 Lyell^ in favour of transmutation of species but against 

 the Idea of transition between species. The letter contains 

 no reference to Natural Selection, but only to the direct 

 action of external conditions and to laws analogous to 

 those of chemical change, where one substance passes 

 into another without intermediate stages, e. g. by the 

 substitution of one element for another. ' I have a sort 

 of notion that similar laws of definite combination rule 

 over the modifications of organic bodies, and that in 

 passing from species to species " Natura fecit saltum".' 

 And yet, In October, 1859,^ Canon H. B. Tristram, writing 



^ Life and Letters of Thomas Henry Huxley, London, 1900, vol. i, p. 159. 

 ' Ihid, p. 173, ^ In The Ibis, vol. i. 



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