1 85 5.] MUTABILITY OF SPECIES. 49 



place, and have written to Baily about prices, &c. &c. Some- 

 time (when you are better) I should like very much to hear 

 a little about your " Little Call Duck " ; why so called ? And 

 where you got it ? and what it is like ? . . . I was so ignorant 

 I did not even know there were three varieties of Dorking 

 fowl : how do they differ ? . . . 



I forget whether I ever told you what the object of my 

 present work is, it is to view all facts that I can master 

 (eheu, eheu, how ignorant I find I am) in Natural History 

 (as on geographical distribution, palaeontology, classification, 

 hybridism, domestic animals and plants, &c. &c. &c.) to see 

 how far they favour or are opposed to the notion that wild 

 species are mutable or immutable : I mean with my utmost 

 power to give all arguments and facts on both sides. I have 

 a number of people helping me in every way, and giving me 

 most valuable assistance ; but I often doubt whether the 

 subject will not quite overpower me. 



So much for the quasi-business part of my letter. I am 

 very very sorry to hear so indifferent an account of your 

 health : with your large family your life is very precious, and 

 I am sure with all your activity and goodness it ought to 

 be a happy one, or as happy as can reasonably be expected 

 with all the cares of futurity on one. 



One cannot expect the present to be like the old Crux- 

 major days at the foot of those noble willow stumps, the 

 memory of which I revere. I now find my little entomology, 

 which I wholly owe to you, comes in very useful. I am very 

 glad to hear that you have given yourself a rest from Sunday 

 duties. How much illness you have had in your life ! 

 Farewell, my dear Fox. I assure you I thank you heartily 

 for your proffered assistance."] 



C. Darwin to W. D. Fox. 



Down, May 7th [1855]. 

 My DEAR Fox, My correspondence has cost you a deal of 

 trouble, though this note will not. I found yours on my return 

 VOL. II. E 



