LETTER 756. TO F.M. BALFOUR. Down, September 4th, 1880.

I hope that you will not think me a great bore, but I have this minute finished reading your address at the British Association; and 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. (756/1. Presidential address delivered by Prof. F.M. Balfour before the Biological Section at the British Association meeting at Swansea (1880).) The recent progress of embryology is indeed splendid. 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, and your address will make it the more interesting to read, though I fear that my want of knowledge will make parts unintelligible to me. (756/2. "A Treatise on Comparative Embryology," 2 volumes. London, 1880.) 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, and 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 (756/3. See Letter 757.); and all this takes place without any nervous system! I think that such facts should be kept in mind when speculating on the genesis of the nervous system. I always feel a malicious pleasure when a priori conclusions are knocked on the head: and therefore I felt somewhat like a devil when I read your remarks on Herbert Spencer (756/4. Prof. Balfour discussed Mr. Herbert Spencer's views on the genesis of the nervous system, and expressed the opinion that his hypothesis was not borne out by recent discoveries. "The discovery that nerves have been developed from processes of epithelial cells gives a very different conception of their genesis to that of Herbert Spencer, which makes them originate from the passage of nervous impulses through a track of mingled colloids..." (loc. cit., page 644.))...Our recent visit to Cambridge was a brilliant success to us all, and will ever be remembered by me with much pleasure.