294: THE SPREAD OF EVOLUTION. [ch. xiv. 



Modifications thus caused, which are neither of advantage 

 nor disadvantage to the modified organism, would be espe- 

 cially favoured, as I can now see chiefly through your obser- 

 vations, by isolation, in a small area, where only a few indi- 

 viduals lived under nearly uniform conditions." 



It has been supposed that such statements indicate a 

 serious change of front on my father's part. As a matter of 

 fact the first edition of the Origin contains the words, " I 

 am convinced that natural selection has been the main but 

 not the exclusive means of modification." Moveover, any 

 alteration that his views may have undergone was due not 

 to a change of opinion, but to change in the materials on 

 which a judgment was to be formed. Thus he wrote to 

 Wagner in the above quoted letter : 



" When I wrote the Origin, and for some years after- 

 wards, I could find little good evidence of the direct action 

 of the environment ; now there is a large body of evidence." 



With the possibility of such action of the environment 

 he had of course been familiar for many years. Thus he 

 wrote to Mr. Davidson in 1861 : 



" My greatest trouble is, not being able to weigh the di- 

 rect effects of the long-continued action of changed condi- 

 tions of life without any selection, with the action of selec- 

 tion on mere accidental (so to speak) variability. I oscillate 

 much on this head, but generally return to my belief that 

 the direct action of the conditions of life has not been great. 

 At least this direct action can have played an extremely 

 small part in producing all the numberless and beautiful 

 adaptations in every living creature." 



And to Sir Joseph Hooker in the following year : 



" I hardly know why I am a little sorry, but my present 

 work is leading me to believe rather more in the direct ac- 

 tion of physical conditions. I presume I regret it, because 

 it lessens the glory of Natural Selection, and is so confound- 

 edly doubtful. Perhaps I shall change again when I get 

 all my facts under one point of view, and a pretty hard job 

 this will be." 



Reference has already been made to the growth of his 

 book on the Expression of the Emotions out of a projected 

 chapter in the Descent of Man. 



It was published in the autumn of 1872. The edition 

 consisted of 7000, and of these 5267 copies were sold at Mr. 

 Murray's sale in November. Two thousand were printed at 

 the end of the year, and this proved a misfortune, as they 



