xvi 



make observations on the effects of use and disuse, experiments on 

 seeds, and so on, while resuming his industrious collection of facts, 

 with a view " to see how far they favour or are opposed to the notion 

 that wild species are mutable or immutable, I mean with my utmost 

 power to give all arguments and facts on both sides. I have a number 

 of people helping me every way, and giving me most valuable assis- 

 tance ; but I often doubt whether the subject will not quite over- 

 power me." (II, p. 49.) 



Early in 1856, on Lyell's advice, Darwin began to write out his 

 views on the origin of species on a scale three or four times as exten- 

 sive as that of the work published in 1859. In July of the same 

 year he gave a brief sketch of his theory in a letter to Asa Gray ; 

 and, in the year 1857, his letters to his correspondents show him to 

 be busily engaged on wha,t he calls his " big book." (II, pp. 85, 94.) 

 In May, 1857, Darwin writes to Wallace : " I am now preparing 

 my work [on the question how and in what way do species and 

 varieties differ from each other] for publication, but I find the subject 

 so very large, that, though I have written many chapters, I do not 

 suppose I shall go to press for two years." (II, p. 95.) In December, 

 1857, he writes, in the course of a long letter to the same corre- 

 spondent, " I am extremely glad to hear that you are attending 

 to distribution in accordance with theoretical ideas. I am a firm 

 believer that without speculation there is no good and original 

 observation." (II, p. 108.)* In June, 1858, he received from Mr. 

 Wallace, then in the Malay Archipelago, an ' Essay on the tendency 

 of varieties to depart indefinitely from the original type,' of which 

 Darwin says, " If Wallace had my MS. sketch written out in 1842 

 he could not have made a better short abstract ! Even his terms 

 stand now as heads of my chapters. Please return me the MS., 

 which he does not say he wishes me to publish, but I shall, of course, 

 at once write and offer to send it to any journal. So all my origin- 

 ality, whatever it may amount to, will be smashed, though my book, 

 if ever it will have any value, will not be deteriorated ; as all the labour 

 consists in the application of the theory." (II, p. 116.) 



Thus, Darwin's first impulse was to publish Wallace's essay without 

 note or comment of his own. But, on consultation with Lyell and 

 Hooker, the latter of whom had read the sketch of 1844, they suggested, 

 as an undoubtedly more equitable course, that extracts from the MS. oif 

 1844 and from the letter to Dr. Asa Gray should be communicated to 

 the Linnean Society along with Wallace's essay. The joint commu- 

 nication was read on July 1, 1858, and published under the title ' On 

 the Tendency of Species to form Varieties ; and on the Perpetuation 



* The last remark contains a pregnant truth, but it must be confessed it hardly 

 squares with the declaration in the ' Autobiography ' (I, p. 83) that he worked on 

 true Baconian principles." 



