C. Darwin to J. D. Hooker. Down, April 12th [1857]. MY DEAR HOOKER,-Your letter has pleased me much, for I never can get it out of my head, that I take unfair advantage of your kindness, as I receive all and give nothing. What a splendid discussion you could write on the whole subject of variation! The cases discussed in your last note are valuable to me (though odious and damnable), as showing how profoundly ignorant we are on the causes of variation. I shall just allude to these cases, as a sort of sub-division of polymorphism a little more definite, I fancy, than the variation of, for instance, the Rubi, and equally or more perplexing. I have just been putting my notes together on variations apparently due to the immediate and direct action of external causes; and I have been struck with one result. The most firm sticklers for independent creation admit, that the fur of the same species is thinner towards the south of the range of the same species than to the north-that the same shells are brighter-coloured to the south than north; that the same [shell] is paler-coloured in deep water-that insects are smaller and darker on mountains-more livid and testaceous near sea -that plants are smaller and more hairy and with brighter flowers on mountains: now in all such, and other cases, distinct species in the two zones follow the same rule, which seems to me to be most simply explained by species, being only strongly marked varieties, and therefore following the same laws as recognised and admitted varieties. I mention all this on account of the variation of plants in ascending mountains; I have quoted the foregoing remark only generally with no examples, for I add, there is so much doubt and dispute what to call varieties; but yet I have stumbled on so many casual remarks on varieties of plants on mountains being so characterised, that I presume there is some truth in it. What think you? Do you believe there is any tendency in varieties, as generally so called, of plants to become more hairy and with proportionally larger and brighter-coloured flowers in ascending a mountain? I have been interested in my "weed garden," of 3X2 feet square: I mark each seedling as it appears, and I am astonished at the number that come up, and still more at the number killed by slugs, &c. Already 59 have been so killed; I expected a good many, but I had fancied that this was a less potent check than it seems to be, and I attributed almost exclusively to mere choking, the destruction of the seedlings. Grass-seedlings seem to suffer much less than exogens. C. Darwin to J. D. Hooker. Moor Park, Farnham [April (?) 1857]. MY DEAR HOOKER,-Your letter has been forwarded to me here, where I am undergoing hydropathy for a fortnight, having been here a week, and having already received an amount of good which is quite incredible to myself and quite unaccountable. I can walk and eat like a hearty Christian, and even my nights are good. I cannot in the least understand how hydropathy can act as it certainly does on me It dulls one's brain splendidly; I have not thought about a single species of any kind since leaving home. Your note has taken me aback; I thought the hairiness, &c., of Alpine species was generally admitted; I am sure I have seen it alluded to a score of times Falconer was haranguing on it the other day to me Meyen or Gay, or some such fellow (whom you would despise), I remember, makes some remark on Chilian Cordillera plants. Wimmer has written a little book on the same lines, and on varieties being so characterised in the Alps. But after writing to you, I confess I was staggered by finding one man (Moquin-Tandon, I think) saying that Alpine flowers are strongly inclined to be white, and Linnæus saying that cold makes plants apetalous, even the same species! Are Arctic plants often apetalous? My general belief from my compiling work is quite to agree with what you say about the little direct influence of climate; and I have just alluded to the hairiness of Alpine plants as an exception. The odoriferousness would be a good case for me if I knew of varieties being more odoriferous in dry habitats. I fear that I have looked at the hairiness of Alpine plants as so generally acknowledged that I have not marked passages, so as at all to see what kind of evidence authors advance. I must confess, the other day, when I asked Falconer, whether he knew of individual plants losing or acquiring hairiness when transported, he did not. But now this second, my memory flashes on me, and I am certain I have somewhere got marked a case of hairy plants from the Pyrenees losing hairs when cultivated at Montpellier. Shall you think me very impudent if I tell you that I have sometimes thought that (quite independently of the present case), you are a little too hard on bad observers; that a remark made by a bad observer cannot be right; an observer who deserves to be damned you would utterly damn. I feel entire deference to any remark you make out of your own head; but when in opposition to some poor devil, I somehow involuntarily feel not quite so much, but yet much deference for your opinion. I do not know in the least whether there is any truth in this my criticism against you, but I have often thought I would tell you it. I am really very much obliged for your letter, for, though I intended to put only one sentence and that vaguely, I should probably have put that much too strongly. Ever, my dear Hooker, yours most truly, C. DARWIN. P. S. This note, as you see, has not anything requiring an answer. The distribution of fresh-water molluscs has been a horrid incubus to me, but I think I know my way now; when first hatched they are very active, and I have had thirty or forty crawl on a dead duck's foot; and they cannot be jerked off, and will live fifteen and even twenty-four hours out of water. [The following letter refers to the expedition of the Austrian frigate Novara; Lyell had asked my father for suggestions.] C. Darwin to C. Lyell. Down, Feb. 11th [1857]. MY DEAR LYELL,-I was glad to see in the newspapers about the Austrian Expedition. I have nothing to add geologically to my notes in the Manual.* I do not know whether the Expedition is tied down to call at only fixed spots. But if there be any choice or power in the scientific men to influence the places-this would be most desirable. It is my most deliberate conviction that nothing would aid more, Natural History, than careful collecting and investigating all the productions of the most isolated islands, especially of the southern hemisphere. Except Tristan d'Acunha and Kerguelen Land, they are very imperfectly known; and even at Kerguelen Land, how much there is to make out about the lignite beds, and whether there are signs of old Glacial action. Every sea shell and insect and plant is of value from such spots. Some one in the Expedition especially ought to have Hooker's New Zealand Essay. What grand work to explore Rodriguez, with its fossil birds, and little known productions of every kind. Again the Seychelles, which, with the Cocos so near, must be a remnant of some older land. The outer island of Juan Fernandez is little known. The investigation of these little spots by a band of naturalists would be grand; St. Paul's and Amsterdam would be glorious, botanically, and geologically. Can you not recommend them to get my 'Journal' and 'Volcanic Islands' on account of the Galapagos. If they come from the north it will be a shame and a sin if they do not call at Cocos Islet, one of the Galapagos. I always regretted that I was not able to examine the great * The article "Geology" in the Admiralty Manual of Scientific En craters on Albemarle Island, one of the Galapagos. In New Zealand urge on them to look out for erratic boulders and marks of old glaciers. Urge the use of the dredge in the Tropics; how little or nothing we know of the limit of life downward in the hot seas? My present work leads me to perceive how much the domestic animals have been neglected in out of the way countries. The Revillagigedo Island off Mexico, I believe, has never been trodden by foot of naturalist. If the expedition sticks to such places as Rio, Cape of Good Hope, Ceylon and Australia, &c., it will not do much. Ever yours most truly, C. DARWIN, [The following passage occurs in a letter to Mr. Fox, February 22, 1857, and has reference to the book on Evolution on which he was still at work. The remainder of the letter is made up in details of no interest: "I am got most deeply interested in my subject; though I wish I could set less value on the bauble fame, either present or posthumous, than I do, but not I think, to any extreme degree: yet, if I know myself, I would work just as hard, though with less gusto, if I knew that my book would be pub lished for ever anonymously."] C. Darwin to A. R. Wallace. Moor Park, May 1st, 1857. MY DEAR SIR,—I am much obliged for your letter of October 10th, from Celebes, received a few days ago; in a laborious undertaking, sympathy is a valuable and real encouragement. By your letter and even still more by your |