50 



CHAPTER VII. 



GROWTH OF THE " ORIGIN " (continued) - - CORRE- 

 SPONDENCE WITH FRIENDS. 



THE great periods of Darwin's scientific career are 

 marked by intimate friendships, which must be 

 taken into account in attempting to trace his mental 

 development. Henslow was his intimate friend at 

 Cambridge and during the voyage of the Beagle. 

 The influence of Lyell, through his writings, was of 

 the utmost importance during the voyage, and was 

 deepened by the close personal contact which took 

 place on Darwin's return. Sir Joseph Hooker was 

 his most intimate friend during the growth of the 

 " Origin of Species." 



Although Hooker met Darwin in 1839, their 

 friendship did not begin until four years later, when 

 the former returned from the Antarctic Expedition. 

 On January llth, 1844, Darwin wrote admitting his 

 conclusions on the question of evolution : " At last 

 gleams of light have come," he says, "and I am 

 almost convinced (quite contrary to the opinion I 

 started with) that species are not (it is like con- 

 fessing a murder) immutable" ("Life and Letters," 

 Vol. II. p. 23). 



From this point onwards his letters, especially to 



