93 WORK ON 'MAN.' [1868. 



armatus, translated by Mr. Dallas, has just appeared in our 

 ' Annals and Magazine of Natural History/ and I have read it 

 with the greatest interest. I never thought that I should 

 live to hear of a hybrid Balanus ! I am very glad that you 

 have seen the cement tubes ; they appear to me extremely 

 curious, and, as far as I know, you are the first man who has 

 verified my observations on this point. 



With most cordial thanks for all your kindness, my 

 dear Sir, 



Yours very sincerely, 



C. Darwin. 



C. Darwin to A. De Candolle. 



Down, July 6, 1868. 

 My DEAR SIR, — I return you my sincere thanks for your 

 long letter, which I consider a great compliment, and which 

 is quite full of most interesting facts and views. Your 

 references and remarks will be of great use should a new 

 edition of my book * be demanded, but this is hardly prob- 

 able, for the whole edition was sold within the first week, 

 and another large edition immediately reprinted, which I 

 should think would supply the demand for ever. You ask 

 me when I shall publish on the 'Variation of Species in 

 a State of Nature.' I have had the MS. for another volume 

 almost ready during several years, but I was so much 

 fatigued by my last book that I determined to amuse myself 

 by publishing a short essay on the ' Descent of Man. 5 I was 

 partly led to do this by having been taunted that I concealed 

 my views, but chiefly from the interest which I had long 

 taken in the subject. Now this essay has branched out into 

 some collateral subjects, and I suppose will take me more 

 than a year to complete. I shall then begin on 'Species,' 

 but my health makes me a very slow workman. I hope that 

 you will excuse these details, which I have given to show 



* ' Variation of Animals and Plants.' 



