Dear Sir

I am very much obliged for your letter and the interesting facts which it contains, and which are new to me.² But I am at present so much engaged with other subjects that I cannot fully consider them; and even if I had time, I do not suppose that I should have anything to say worth printing in a scientific Journal. It would obviously be absurd in me to allow a mere note of thanks from me to be printed. Whenever I have to bring out a corrected edition of my book, I will well consider your remarks (which I hope that you will send to Nature)³ but the difficulty will be that my friends tell me that I have already introduced too many facts, and that I ought to prune, rather than to introduce more.⁴

With my best thanks, I remain | Dear Sir | Yours faithfully | Ch. Darwin

P.S. I have received your second note with its ingenious suggestion for which many thanks. You will of course include this with any notice which you may send to Nature.⁵