My dear Sir.

The recent important changes in taxation² will probably have absorbed much of your attention but at some future time when you have a little leisure and when you have read my “Origin of Species” I should esteem it a singular favour if you would send me any general criticisms—³ I do not mean of unreasonable length, but such as you could include in a letter. I have always admired your various memoirs so much that I should be eminently glad to receive your opinion, which might be of real service to me.⁴

Pray do not suppose that I expect to convert or pervert you; if I could stagger you in ever so slight a degree I should be satisfied; nor fear to annoy me by severe criticisms for I have had some hearty kicks from some of my best friends. If it would not be disagreeable to you to send me your opinion I certainly should be truly obliged—

I find that I have not put clearly how, as it seems to me, the general argument ought fairly to be viewed; namely, natural selection as a mere hypothesis (rendered in some slight degree probable by the analogy of domestication and the struggle for existence.) which hypothesis has to be judged of by whether it explains a number of facts in Geographical Distribution, Geological Succession    Classification, Homology, Embryology &c. If it does explain such facts then the hypothesis seems to me to rise in rank to a theory.

Pray forgive me troubling you with this note, and believe me | My dear Sir | Yours sincerely | C. Darwin.