150 THE WRITING OF THE 'ORIGIN OF SPECIES.' [1859. 



capitulation) on Affinities, Homologies, Embryology, &c., 

 and the facts seem to me to come out very strong for 

 mutability of species. 



I have been much interested in working out the chapter. 



I shall now, thank God, begin looking over old first chapters 

 for press. 



But my health is now so very poor, that even this will take 

 me long. 



C. Darwin to W. D. Fox. 



Down, [March] 24th [1859]. 



My DEAR Fox, It was very good of you to write to me 

 in the midst of all your troubles, though you seem to have 

 got over some of them, in the recovery of your wife's and 

 your own health, I had not heard lately of your mother's 

 health, and am sorry to hear so poor an account. But as 

 she does not suffer much, that is the great thing ; for mere 

 life I do not think is much valued by the old. What a time 

 you must have had of it, when you had to go backwards 

 and forwards. 



We are all pretty well, and our eldest daughter is improving. 

 I can see daylight through my work, and am now finally 

 correcting my chapters for the press ; and I hope in a month 

 or six weeks to have proof-sheets. I am weary of my work. 

 It is a very odd thing that I have no sensation that I over- 

 work my brain ; but facts compel me to conclude that my 

 brain was never formed for much thinking. We are resolved 

 to go for two or three months, when I have finished, to Ilkley, 

 or some such place, to see if I can anyhow give my health 

 a good start, for it certainly has been wretched of late, and 

 has incapacitated me for everything. You do me injustice 

 when you think that I work for fame ; I value it to a certain 

 extent ; but, if I know myself, I work from a sort of instinct 

 to try to make out truth. How glad I should be if you could 

 sometime come to Down ; especially when I get a little better, 



