Letter 203. To A.R. Wallace. Down, October, 12th and 13th [1867].

I ordered the journal (203/1. "Quarterly Journal of Science," October, 1867, page 472. A review of the Duke of Argyll’s "Reign of Law.") a long time ago, but by some oversight received it only yesterday, and read it. You will think my praise not worth having, from being so indiscriminate; but if I am to speak the truth, I must say I admire every word. You have just touched on the points which I particularly wished to see noticed. I am glad you had the courage to take up Angraecum (203/2. Angraecum sesquipedale, a Madagascan orchid, with a whiplike nectary, 11 to 12 inches in length, which, according to Darwin ("Fertilisation of Orchids," Edition II., page 163), is adapted to the visits of a moth with a proboscis of corresponding length. He points out that there is no difficulty in believing in the existence of such a moth as F. Muller has described ("Nature," 1873, page 223)—a Brazilian sphinx-moth with a trunk of 10 to 11 inches in length. Moreover, Forbes has given evidence to show that such an insect does exist in Madagascar ("Nature," VIII., 1873, page 121). The case of Angraecum was put forward by the Duke of Argyll as being necessarily due to the personal contrivance of the Deity. Mr. Wallace (page 476) shows that both proboscis and nectary might be increased in length by means of Natural Selection. It may be added that Hermann Muller has shown good grounds for believing that mutual specialisation of this kind is beneficial both to insect and plant.) after the Duke’s attack; for I believe the principle in this case may be widely applied. I like the figure, but I wish the artist had drawn a better sphinx. With respect to beauty, your remarks on hideous objects and on flowers not being made beautiful except when of practical use to them, strike me as very good. On this one point of beauty I can hardly think that the Duke was quite candid. I have used in the concluding paragraph of my present book precisely the same argument as you have, even bringing in the bull-dog (203/3. "Variation of Animals and Plants," Edition I., Volume II., page 431: "Did He cause the frame and mental qualities of the dog to vary in order that a breed might be formed of indomitable ferocity, with jaws fitted to pin down the bull for man’s brutal sport?"), with respect to variations not having been specially ordained. Your metaphor of the river (203/4. See Wallace, op. cit., pages 477-8. He imagines an observer examining a great riversystem, and finding everywhere adaptations which reveal the design of the Creator. "He would see special adaptation to the wants of man in broad, quiet, navigable rivers, through fertile alluvial plains that would support a large population, while the rocky streams and mountain torrents were confined to those sterile regions suitable only for a small population of shepherds and herdsmen.’) is new to me, and admirable; but your other metaphor, in which you compare classification and complex machines, does not seem to me quite appropriate, though I cannot point out what seems deficient. The point which seems to me strong is that all naturalists admit that there is a natural classification, and it is this which descent explains. I wish you had insisted a little more against the "North British" (203/5. At page 485 Mr. Wallace deals with Fleeming Jenkin’s review in the "North British Review," 1867. The review strives to show that there are strict limits to variation, since the most rigorous and long-continued selection does not indefinitely increase such a quality as the fleetness of a racehorse. On this Mr. Wallace remarks that "this argument fails to meet the real question," which is, not whether indefinite change is possible, "but whether such differences as do occur in nature could have been produced by the accumulation of variations by selection.") on the reviewer assuming that each variation which appears is a strongly marked one; though by implication you have made this very plain. Nothing in your whole article has struck me more than your view with respect to the limit of fleetness in the racehorse and other such cases: I shall try and quote you on this head in the proof of my concluding chapter. I quite missed this explanation, though in the case of wheat I hit upon something analogous. I am glad you praise the Duke’s book, for I was much struck with it. The part about flight seemed to me at first very good; but as the wing is articulated by a ball-and-socket joint, I suspect the Duke would find it very difficult to give any reason against the belief that the wing strikes the air more or less obliquely. I have been very glad to see your article and the drawing of the butterfly in "Science Gossip." By the way, I cannot but think that you push protection too far in some cases, as with the stripes on the tiger. I have also this morning read an excellent abstract in the "Gardeners’ Chronicle" of your paper on nests. (203/6. An abstract of a paper on "Birds’ Nests and Plumage," read before the British Association: see "Gard. Chron." 1867, page 1047.) I was not by any means fully converted by your letter, but I think now I am so; and I hope it will be published somewhere in extenso. It strikes me as a capital generalisation, and appears to me even more original than it did at first...

I have finished Volume I. of my book ["Variation of Animals and Plants"], and I hope the whole will be out by the end of November. If you have the patience to read it through, which is very doubtful, you will find, I think, a large accumulation of facts which will be of service to you in future papers; and they could not be put to better use, for you certainly are a master in the noble art of reasoning.