THE LIFE AND WORK OF DARWIN 211 



tend to be preserved, and unfavourable ones to be 

 destroyed. The result of this would be the formation 

 of new species. Here, then, I had at last got a theory 

 by which to work ; but I was so anxious to avoid 

 prejudice that I determined not for some time to 

 write even the briefest sketch of it. In June 1842, 

 I first allowed myself the satisfaction of writing a 

 very brief abstract of my theory in pencil, in thirty- 

 five pages, and this was enlarged during the summer 

 of 1844 into one of 230 pages." 



Not till 1858 was the theory published, and then 

 only on pressure of the strongest character being 

 brought to bear on him. On June 1 8th, 1858, 

 Darwin, having convinced himself and accumulated 

 the evidence and proofs he wanted, was at last at 

 work on the book, when he received, most unex- 

 pectedly, Wallace's MS. from Ternate, in which 

 the Theory of Natural Selection was set forth 

 clearly and decisively, almost in Darwin's own 

 words. Darwin wished to publish Wallace's paper 

 without reference to his own work ; but at the 

 urgent solicitation of Lyell and Hooker he consented 

 to allow extracts from his own MS. of 1844, 

 together with a letter to Asa Gray of 1857, to be 

 read before the Linnean Society on July 1st, 1858. 



Darwin was at this time forty-nine years of age, 

 and Wallace thirty-five. On Darwin's part this 

 publication was the result of twenty-one yea rs_of 

 deliberate work ; and of viewsTbrmed nineteen 

 years "Beforehand, and actually written out in MS. 

 of 230 pages fourteen years previously. The dual 

 authorship of the " Theory," and its simultaneous 



