xiv INTRODUCTION 



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." 



It is surprising that Malthus should have been 

 needed to give him the clue, when in the Note Book 

 of 1837 there should occur however obscurely ex- 

 pressed the following forecast 1 of the importance 

 of the survival of the fittest. "With respect to 

 extinction, we can easily see that a variety of the 

 ostrich (Petise 2 ), may not be well adapted, and 

 thus perish out; or on the other hand, like Or- 

 pheus 3 , being favourable, many might be produced. 

 This requires the principle that the permanent 

 variations produced by confined breeding and 

 changing circumstances are continued and pro- 

 duce^!) according to the adaptation of such circum- 

 stances, and therefore that death of species is a 

 consequence (contrary to what would appear in 

 America) of non-adaptation of circumstances." 



I can hardly doubt, that with his knowledge of 

 the interdependence of organisms and the tyranny 

 of conditions, his experience would have crystallized 

 out into " a theory by which to work " even without 

 the aid of Malthus. 



In my father's Autobiography 4 he writes, "In 

 June 1842 I first allowed myself the satisfaction of 

 writing a very brief abstract of my theory in pencil 

 in 35 pages; and this was enlarged during the summer 

 of 1844 into one of 230 pages 5 , which I had fairly 

 copied out and still possess." It is the first of these 

 Essays, the one in 35 pages, which is now printed 

 under the title The Foundations of the Origin of 

 Species. 



1 Life and Letters, ii. p. 8. 2 Avestruz Petise, i.e. Rhea Darwini. 



3 A bird. 



4 Life and Letters, i. p. 84. 



5 It contains as a fact 231 pp. It is a strongly bound folio, interleaved 

 with blank pages, as though for notes and additions. His own MS. from 

 which it was copied contains 189 pp. 



