xii INTRODUCTION 



effective degree of steadiness or brightness. I 

 think so because in his Pocket Book under the 

 date 1837 he wrote, " In July opened first note-book 

 on 'transmutation of species.' Had been greatly 

 struck from about month of previous March 1 on 

 character of South American fossils, and species 

 on Galapagos Archipelago. These facts origin (es- 

 pecially latter), of all my views." But he did not visit 

 the Galapagos till 1835 and I therefore find it hard 

 to believe that his evolutionary views attained any 

 strength or permanence until at any rate quite late 

 in the voyage. The Galapagos facts are strongly 

 against Huxley's view, for Darwin's attention was 

 "thoroughly aroused 2 ' by comparing the birds shot 

 by himself and by others on board. The case must 

 have struck him at once, without waiting for accu- 

 rate determinations, as a microcosm of evolution. 



It is also to be noted, in regard to the remains 

 of extinct animals, that, in the above quotation from 

 his Pocket Book, he speaks of March 1837 as the 

 time at which he began to be "greatly struck on 

 character of South American fossils," which sug- 

 gests at least that the impression made in 1832 

 required reinforcement before a really powerful 

 effect was produced. 



We may therefore conclude, I think, that 

 the evolutionary current in my father's thoughts 

 had continued to increase in force from 1832 

 onwards, being especially reinforced at the Gala- 

 pagos in 1835 and again in 1837 when he was 

 overhauling the results, mental and material, of 

 his travels. And that when the above record in 

 the Pocket Book was made he unconsciously mini- 

 mised the earlier beginnings of his theorisings, and 

 laid more stress on the recent thoughts which were 



1 In this citation the italics are mine. 



2 Journal of Researches, Ed. 1860, p. 394. 



