My dear Balfour

I hope that you will not think me a great bore, but I have this minute finished reading your address at the B. Assocⁿ.; & it has interested me so much that I cannot resist thanking you heartily for the pleasure derived from it, not to mention the honour which you have done me. The recent progress of embryology is indeed splendid.¹ I have been very stupid not to have hitherto read your book, but I have had of late no spare time; I have now ordered it, & your address will make it the more interesting to read, though I fear that my want of knowledge will make parts unintelligible to me.—² In my recent work on plants I have been astonished to find to how many very different stimuli the same small part,, viz the tip of the radicle, is sensitive & has the power of transmitting some influence to the adjoining part of the radicle, exciting it to bend to or from the source of irritation according to the needs of the plant; & all this takes place without any nervous system! I think that such facts sh^d. be kept in mind, when speculating on the genesis of the nervous system.³ I always feel a malicious pleasure when a priori conclusions are knocked on the head; & therefore I felt somewhat like a Devil, when I read your remarks on Herbert Spencer.—⁴ (I hope that you will soon start for the Alps (& cross the glacier to Horace & Ida), for I am sure that you must much need rest.)— Our recent visit to Cambridge was a brilliant success to us all, & will ever be remembered by me with much pleasure.—⁵

Believe me | Yours very sincerely | Charles Darwin