To J. S. Henslow   11 November 1859

My dear Henslow

I have told Murray to send a copy of my Book on species to you, my dear old master in natural history. I fear, however, that you will not approve of your pupil in this case. The book in its present state does not show the amount of labour which I have bestowed on the subject—

If you have time to read it carefully & would take the trouble to point out what parts seem weakest to you & what best, it w^d. be a most material aid to me in writing my bigger book, which I hope to commence in a few months— You know also how highly I value your judgement— But I am not so unreasonable as to wish or expect you to write detailed & lengthy criticisms, but merely a few general remarks pointing out weakest parts—

If you are in ever so slight a degree staggered (which I hardly expect) on the immutability of species, then I am convinced with further reflexion you will become more & more staggered, for this has been the process through which my mind has gone.—

My dear Henslow | Yours affec^ly & | gratefully | C. Darwin