To J. D. Dana 29 September 1
Down Bromley Kent
My dear Sir
I thank you warmly for your letter,2 which like every one received from you, was most kind & interesting.— Your information on the points, on which I asked, is much fuller than I anticipated; I am glad to find that I deduced nearly or quite accurate results from your work with respect to the Crustacea,3 but I am always afraid of falling into error when coming to conclusions on subjects on which I am almost ignorant. Very many thanks, also, for facts about the Caves, which to me is a wonderfully interesting subject: one point I forgot & if there be a specimen of the Cave Rat at New Haven & if you have anyone there au fait at Rodents, I shd. very much wish to know whether its teeth are on the New or Old world type as pointed out by Waterhouse in regard to the great genus Mus.4 But you must not take much trouble on this head, as I have too often given you trouble, & I look at your time as very precious.—
I shall be very curious to see your Embryogeny of N. America!5 What a striking case of vertebræ in tail of young Gar-Pike; I wish with all my heart that Agassiz would publish in detail on his theory of parallelism of geological & embryological development;6 I wish to believe, but have not seen nearly enough as yet to make me a disciple.
I am working very hard at my subject of the variation & origin of species, & am getting M.S. ready for press, but when I shall publish, Heaven only knows, not I fear for a couple of years but whenever I do the first copy shall be sent to you.— I have now been for 19 years with this subject before me; but it is too great for me, especially as my memory is not good. I have of late been chiefly at work on domestic animals, & have now got a considerable collection of skeletons: I am surprised how little this subject has been attended to: I find very grave differences in the skeletons for instance of domestic rabbits, which I think have all certainly descended from one parent wild stock. But Pigeons offer the most wonderful case of variation, & as it seems to me conclusive evidence can be offered that they are all descended from C. livia.
In the case of Pigeons, we have (& in no other case) we have much old literature & the changes in the varieties can be traced. I have now a grand collection of living & dead Pigeons; & I am hand & glove with all sorts of Fanciers, Spital-field weavers & all sorts of odd specimens of the Human species, who fancy Pigeons.—
I know that you are not a believer in the doctrine of single points of creation, in which doctrine I am strongly inclined to believe, from general arguments; but when one goes into detail there are certainly frightful difficulties.7 No facts seem to me so difficult as those connected with the dispersal of Land Mollusca.8 If you ever think of, or hear of, any odd means of dispersal of any organisms I shd. be infinitely obliged for any information; as no one subject gives me such trouble as to account for the presence of the same species of terrestrial productions on oceanic islands; for I cannot swallow the prevalent fashion in England of believing that all islands within recent times have been connected with some continent.—
You will be rather indignant at hearing that I am becoming, indeed I shd. say have become, sceptical on the permanent immutability of species: I groan when I make such a confession, for I shall have little sympathy from those, whose sympathy I alone value.— But anyhow I feel sure that you will give me credit for not having come to so heterodox a conclusion, without much deliberation. How (I think) species become changed I shall explain in my Book, but my views are very different from those of that clever but shallow book, the Vestiges.—9
It is my intention to give fully all the facts in favour of the eternal immutability of species & I have taken as much pains to collect them, as I possibly could do. But what my work will turn out, I know not; but I do know that I have worked hard & honestly at my subject.
Agassiz, if he ever honours me by reading my work, will throw a boulder at me, & many others will pelt me; but magna est veritas &c, & those who write against the truth often, I think, do as much service as those who have divined the truth; so that if I am wrong I must comfort myself with this reflection. It may sound presumptious, but I think I have to a certain extent staggered even Lyell.—10
But I am scribbling (in a very bad handwriting moreover) in a shameful manner all about myself; so I will stop with cordial good wishes for yourself & family, & pray believe me, my dear Sir | Your sincere & heteredox friend | Ch. Darwin
We are all here now much interested in American politics—11 You will think us very impertinent, when I say how fervently we wish you in the North to be free.—
P.S. | I have long thought that geologists not having found this or that form in this or that formation was very poor evidence of such forms not having then existed; in this respect differing, as wide as the poles, from the great Agassiz, who seems to me to retreat a step & take up a new position with a front so bold as to be admirable in a soldier.— Well, in case of cirripedes I thought, as stated in Preface in my Fossil Lepadidæ, that the evidence was so good, that I did believe that no Sessile cirripede existed before the Tertiary period. But yesterday I received from M. Bosquet of Maestricht a beautiful drawing of perfect Chthamalus from the Chalk!!—12
Never again will I put any trust in negative geological evidence.—
Thanks JDD for replies to queries [in 1925]; would like to know whether teeth of cave rat are of New or Old World type.
Wishes Louis Agassiz would publish his theory of parallels of geological and embryological development. "I wish to believe but have not seen nearly enough as yet to make me a disciple."
Is working hard on variations and origin of species, but fears it will be a couple of years before he publishes.
Describes his recent work on rabbits and pigeons.
The dispersal of land Mollusca is a most difficult problem.
Confesses he is sceptical of immutability of species; discusses difficulty of proving it.
- Letter no.
- Charles Robert Darwin
- James Dwight Dana
- Sent from
- Source of text
- Yale University Library: Manuscripts and Archives (Dana Family Papers (MS 164) Series 1, Box 2, folder 44)
- Physical description