Life and Letters of Charles Darwin Volume I Part 40

CHARLES DARWIN TO J.D. HOOKER. December 24th [1856].

...How I do wish I lived near you to discuss matters with. I have just been comparing definitions of species, and stating briefly how systematic naturalists work out their subjects. Aquilegia in the Flora Indica was a capital example for me. It is really laughable to see what different ideas are prominent in various naturalists' minds, when they speak of "species;" in some, resemblance is everything and descent of little weight--in some, resemblance seems to go for nothing, and Creation the reigning idea--in some, descent is the key,--in some, sterility an unfailing test, with others it is not worth a farthing. It all comes, I believe, from trying to define the undefinable. I suppose you have lost the odd black seed from the birds' dung, which germinated,--anyhow, it is not worth taking trouble over. I have now got about a dozen seeds out of small birds' dung. Adios,

My dear Hooker, ever yours, C. DARWIN.

CHARLES DARWIN TO ASA GRAY. Down, January 1st [1857?].

My dear Dr Gray,

I have received the second part of your paper ('Statistics of the Flora of the Northern United States.' "Silliman's Journal", 1857.), and though I have nothing particular to say, I must send you my thanks and hearty admiration. The whole paper strikes me as quite exhausting the subject, and I quite fancy and flatter myself I now appreciate the character of your Flora. What a difference in regard to Europe your remark in relation to the genera makes! I have been eminently glad to see your conclusion in regard to the species of large genera widely ranging; it is in strict conformity with the results I have worked out in several ways. It is of great importance to my notions. By the way you have paid me a GREAT compliment ("From some investigations of his own, this sagacious naturalist inclines to think that [the species of] large genera range over a larger area than the species of small genera do."--Asa Gray, loc. cit.): to be SIMPLY mentioned even in such a paper I consider a very great honour. One of your conclusions makes me groan, viz., that the line of connection of the strictly alpine plants is through Greenland. I should EXTREMELY like to see your reasons published in detail, for it "riles" me (this is a proper expression, is it not?) dreadfully. Lyell told me, that Aga.s.siz having a theory about when Saurians were first created, on hearing some careful observations opposed to this, said he did not believe it, "for Nature never lied."

I am just in this predicament, and repeat to you that, "Nature never lies," ergo, theorisers are always right...

Overworked as you are, I dare say you will say that I am an odious plague; but here is another suggestion! I was led by one of my wild speculations to conclude (though it has nothing to do with geographical distribution, yet it has with your statistics) that trees would have a strong tendency to have flowers with dioecious, monoecious or polygamous structure. Seeing that this seemed so in Persoon, I took one little British Flora, and discriminating trees from bushes according to Loudon, I have found that the result was in species, genera and families, as I antic.i.p.ated. So I sent my notions to Hooker to ask him to tabulate the New Zealand Flora for this end, and he thought my result sufficiently curious, to do so; and the accordance with Britain is very striking, and the more so, as he made three cla.s.ses of trees, bushes, and herbaceous plants. (He says further he shall work the Tasmanian Flora on the same principle.) The bushes hold an intermediate position between the other two cla.s.ses. It seems to me a curious relation in itself, and is very much so, if my theory and explanation are correct. (See 'Origin,'

Edition i., page 100.)

With hearty thanks, your most troublesome friend, C. DARWIN.

CHARLES 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 d.a.m.nable), 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 sh.e.l.ls are brighter-coloured to the south than north; that the same [sh.e.l.l]

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 3 x 2 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, etc. 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.

Gra.s.s-seedlings seem to suffer much less than exogens...

CHARLES 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, etc., 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 Linnaeus 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 pa.s.sages, 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 d.a.m.ned you would utterly d.a.m.n. 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.]

CHARLES DARWIN TO C. LYELL. Down, February 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. (The article "Geology" in the Admiralty Manual of Scientific Enquiry.) 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 sh.e.l.l 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 Seych.e.l.les, 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 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, etc., it will not do much.

Ever yours most truly, C. DARWIN.

[The following pa.s.sage 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 published for ever anonymously."]

CHARLES 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 paper ('On the law that has regulated the introduction of new species.'--Ann. Nat. Hist., 1855.) in the Annals, a year or more ago, I can plainly see that we have thought much alike and to a certain extent have come to similar conclusions. In regard to the Paper in the Annals, I agree to the truth of almost every word of your paper; and I dare say that you will agree with me that it is very rare to find oneself agreeing pretty closely with any theoretical paper; for it is lamentable how each man draws his own different conclusions from the very same facts. This summer will make the 20th year (!) since I opened my first note-book, on the question how and in what way do species and varieties differ from each other. I am now preparing my work for publication, but I find the subject so very large, that though I have written many chapters, I do not suppose I shall go to press for two years. I have never heard how long you intend staying in the Malay Archipelago; I wish I might profit by the publication of your Travels there before my work appears, for no doubt you will reap a large harvest of facts. I have acted already in accordance with your advice of keeping domestic varieties, and those appearing in a state of nature, distinct; but I have sometimes doubted of the wisdom of this, and therefore I am glad to be backed by your opinion. I must confess, however, I rather doubt the truth of the now very prevalent doctrine of all our domestic animals having descended from several wild stocks; though I do not doubt that it is so in some cases. I think there is rather better evidence on the sterility of hybrid animals than you seem to admit: and in regard to plants the collection of carefully recorded facts by Kolreuter and Gaertner (and Herbert,) is ENORMOUS. I most entirely agree with you on the little effects of "climatal conditions," which one sees referred to ad nauseam in all books: I suppose some very little effect must be attributed to such influences, but I fully believe that they are very slight. It is really IMPOSSIBLE to explain my views (in the compa.s.s of a letter), on the causes and means of variation in a state of nature; but I have slowly adopted a distinct and tangible idea,--whether true or false others must judge; for the firmest conviction of the truth of a doctrine by its author, seems, alas, not to be the slightest guarantee of truth!...

CHARLES DARWIN TO J.D. HOOKER. Moor Park, Sat.u.r.day [May 2nd, 1857].

My dear Hooker,

You have shaved the hair off the Alpine plants pretty effectually.

The case of the Anthyllis will make a "tie" with the believed case of Pyrenees plants becoming glabrous at low levels. If I DO find that I have marked such facts, I will lay the evidence before you. I wonder how the belief could have originated! Was it through final causes to keep the plants warm? Falconer in talk coupled the two facts of woolly Alpine plants and mammals. How candidly and meekly you took my Jeremiad on your severity to second-cla.s.s men. After I had sent it off, an ugly little voice asked me, once or twice, how much of my n.o.ble defence of the poor in spirit and in fact, was owing to your having not seldom smashed favourite notions of my own. I silenced the ugly little voice with contempt, but it would whisper again and again. I sometimes despise myself as a poor compiler as heartily as you could do, though I do NOT despise my whole work, as I think there is enough known to lay a foundation for the discussion on the origin of species. I have been led to despise and laugh at myself as a compiler, for having put down that "Alpine plants have large flowers," and now perhaps I may write over these very words, "Alpine plants have small or apetalous flowers!"...

CHARLES DARWIN TO J.D. HOOKER. Down, [May] 16th [1857].

My dear Hooker,

You said--I hope honestly--that you did not dislike my asking questions on general points, you of course answering or not as time or inclination might serve. I find in the animal kingdom that the proposition that any part or organ developed normally (i.e., not a monstrosity) in a species in any HIGH or UNUSUAL degree, compared with the same part or organ in allied species, tends to be HIGHLY VARIABLE. I cannot doubt this from my ma.s.s of collected facts. To give an instance, the Cross-bill is very abnormal in the structure of its bill compared with other allied Fringillidae, and the beak is EMINENTLY VARIABLE. The Himantopus, remarkable from the wonderful length of its legs, is VERY variable in the length of its legs. I could give MANY most striking and curious ill.u.s.trations in all cla.s.ses; so many that I think it cannot be chance.

But I have NONE in the vegetable kingdom, owing, as I believe, to my ignorance. If Nepenthes consisted of ONE or two species in a group with a pitcher developed, then I should have expected it to have been very variable; but I do not consider Nepenthes a case in point, for when a whole genus or group has an organ, however anomalous, I do not expect it to be variable,--it is only when one or few species differ greatly in some one part or organ from the forms CLOSELY ALLIED to it in all other respects, that I believe such part or organ to be highly variable. Will you turn this in your mind? It is an important apparent LAW (!) for me.

Ever yours, C. DARWIN.