1859 LETTER TO LYELL 185 



We also find him combating some of the difficulties in 

 the way of accepting the theory laid before him by Sir 

 Charles Lyell. The veteran geologist had been Darwin's 

 confidant from almost the beginning of his speculations ; he 

 had really paved the way for the evolutionary doctrine by 

 his own proof of geological uniformity, but he shrank from 

 accepting it, for its inevitable extension to the descent of 

 man was repugnant to his feelings. Nevertheless, he would 

 not allow sentiment to stand in the way of truth, and after 

 the publication of the " Origin " it could be said of him — 



Lyell, up to that time a pillar of the anti-transmutationists 

 (who regarded him, ever after, as Pallas Athene may have 

 looked at Dian, after the Endymion affair), declared himself a 

 Darwinian, though not without putting in a serious caveat. 

 Nevertheless, he was a tower of strength, and his courageous 

 stand for truth as against consistency did him infinite honour. 

 — (T. H. H. in Life of Darwin, vol ii. p. 231.) 



To Sir Charles Lyell 



yune 25, 1859. 



My dear Sir Charles — I have endeavoured to meet your 

 objections in the enclosed. — Ever yours, very truly, 



T. H. H. 



The fixity and definite limitation of species, genera, and 

 larger groups appear to me to be perfectly consistent with the 

 theory of transmutation. In other words, I think transmutation 

 may take place without transition. 



Suppose that external conditions acting on species A give 

 rise to a new species, B ; the difference between the two species 

 is a certain definable amount which may be called A-B. Now 

 I know of no evidence to show that the interval between the 

 two species must necessarily be bridged over by a series of 

 forms, each of which shall occupy, as it occurs, a fraction of 

 the distance between A and B. On the contrary, in the history 

 of the Ancon sheep, and of the six-fingered Maltese family, 

 given by Reaumur, it appears that the new form appeared at 

 once in full perfection. 



I may illustrate what I mean by a chemical example. In an 

 organic compound, having a precise and definite composition, 

 you may effect all sorts of transmutations by substituting an 



