More Letters of Charles Darwin — Volume 1 · Charles Darwin
LETTER 103. TO J.D. HOOKER.
(103/1. This letter is of interest as containing a strong expression upon the overwhelming importance of selection.) Down [1860]. Many thanks for Harvey's letter (103/2. W.H. Harvey had been corresponding with Sir J.D. Hooker on the "Origin of Species."), which I will keep a little longer and then return. I will write to him and try to make clear from analogy of domestic productions the part which I believe selection has played. I have been reworking my pigeons and other domestic animals, and I am sure that any one is right in saying that selection is the efficient cause, though, as you truly say, variation is the base of all. Why I do not believe so much as you do in physical agencies is that I see in almost every organism (though far more clearly in animals than in plants) adaptation, and this except in rare instances, must, I should think, be due to selection. Do not forget the Pyrola when in flower. (103/3. In a letter to Hooker, May 22nd, 1860, Darwin wrote: "Have you Pyrola at Kew? if so, for heaven's sake observe the curvature of the pistil towards the gangway to the nectary." The fact of the stigma in insect-visited flowers being so placed that the visitor must touch it on its way to the nectar, was a point which early attracted Darwin's attention and strongly impressed him.) My blessed little Scaevola has come into flower, and I will try artificial fertilisation on it. I have looked over Harvey's letter, and have assumed (I hope rightly) that he could not object to knowing that you had forwarded it to me.
Text from Project Gutenberg, public domain in the United States.