19i GROWTH OF THE ORIGIN OF SPECIES, [ch. x. 



the compass of a letter), on the causes and means of varia- 

 tion in a state of nature ; but I have slowly adopted a dis- 

 tinct and tangible idea, whether true or false others must 

 judge ; for the firmest conviction of the truth of a doctrine 

 by its author, seems, alas, not to be the slightest guarantee of 

 truth ! . . . 



In December 1857 he wrote to the same correspondent: 



" You ask whether I shall discuss * man.' I think I 

 shall avoid the whole subject, as so surrounded with preju- 

 dices ; though I fully admit that it is the highest and most 

 interesting problem for the naturalist. My work, on which 

 I have now been at work more or less for twenty years, will 

 not fix or settle anything ; but I hope it will aid by giving 

 a large collection of fact, with one definite end. I get on 

 very slowly, partly from ill-health, partly from being a very 

 slow worker. I have got about half written ; but I do not 

 suppose I shall publish under a couple of years. - I have now 

 been three whole months on one chapter on Hybridism ! 



I am astonished to see that you expect to remain out 

 three or four years more. What a wonderful deal you will 

 have seen, and what interesting areas the grand Malay 

 Archipelago and the richest parts of South America! I 

 infinitely admire and honour your zeal and courage in the 

 good cause of Natural Science ; and you have my very sin- 

 cere and cordial good wishes for success of all kinds, and 

 may all your theories succeed, except that on Oceanic Isl- 

 ands, on which subject I will do battle to the death." 



And to Fox in February 1858 : 



" I am working very hard at my book, perhaps too hard. 

 It will be very big, and I am become most deeply interested 

 in the way facts fall into groups. I am like Croesus over- 

 whelmed, with my riches in facts, and I mean to make my 

 book as perfect as ever I can. I shall not go to press at 

 soonest for a couple of years." 



The letter which follows, written from his favourite rest- 

 ing place, the Water-Cure Establishment at Moor Park, 

 comes in like a lull before the storm, the upset of all his 

 plans by the arrival of Mr. Wallace's manuscript, a phase in 

 the history of his life to which the next chapter is devoted. 



C. D. to Mrs. Darwin. Moor Park, April [1858]. 



The weather is quite delicious. Yesterday, after writing 

 to you, I strolled a little beyond the glade for an hour and 



