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The Charles Darwin Collection
The Darwin Correspondence Project is publishing letters written by and to the naturalist Charles Darwin (1809–1882). Complete transcripts of letters are being made available through the Project’s website (www.darwinproject.ac.uk) after publication in the ongoing print edition of The Correspondence of Charles Darwin (Cambridge University Press 1985–). Metadata and summaries of all known letters (c. 15,000) appear in Ɛpsilon, and the full texts of available letters can also be searched, with links to the full texts.
Discusses means of seed transport.
Considers the difficulty of deciding which, if any, botanical species are real.
Continued debate on formation of species as a result of retreat from glaciers.
JDH suggests internal powers of species modification, which he knows CD abhors.
He is not sure whether he has seen Subularia flowering above the water, but thinks it probably is an aerial flowerer, at least sometimes.
Has been unable to find an anonymous book on pigeons in the University Library.
CD, attempting to clarify debate, states more of his position. External conditions cause "mere variability". Formation of species due to selection. Relation of an organism to its associates far more important than external conditions.
The Kentucky cave insects (Adelops) are evidently identical to European species of the same genus, some of which are cave insects, others found in damp, dark places.
Writes about suitable mourning clothes and sale of house [Petleys, after death of Sarah Elizabeth Wedgwood I].
Thanks for promise of rabbit carcase and for information about rabbit at Zoological Society’s Garden.
Requests correspondent to ask Mr Vivian for carcase of an old "Creve-coeur" cock. CD has found that the skull in this breed is modified to support its comb.
Responds to CD’s query on Subularia and Limosella. There are discrepancies among authorities on whether Subularia flowers out of water. Limosella certainly flowers out of water.
Letter from school with instructions where to put away his belongings at home.
He is steadily and very hard at work on "Variation" [Natural selection] and finds the whole subject "deeply interesting but horribly perplexed".
Questions JDH on separation of sexes in trees in New Zealand flora.
His observations on Subularia: has never seen it in flower in the air.
Informs CD that the "dishonest mollusks" were collected in May 1855 in Porto Santo. Describes some Madeira species. Though believing in "species" more and more, these may be "mere insular modifications".
Has done New Zealand flora calculations. Results support CD’s theory of necessity of crossing. Trees tend to have separate sexes.
Agassiz has informed him that the mice and rats of Mammoth Cave are American in type.
Alludes to CD’s doubt of the principle that "progress of life on the globe is parallel with the development in different tribes". Outlines his own ideas on the "unfolding of the type-idea" and its "parallelism with the law of development in the embryo".
CD is convinced of relation between separation of sexes and tree-habit.
Recent hard blows against crossing theory.
CD long tormented by land molluscs on oceanic islands; found transport possible experimentally.
Writes of arrangements for the end of the school-term.
Condition of Emma and the new baby [C. W. Darwin].
On the variety of species definitions prevalent among naturalists.
Notes on the comparative rarity of intermediate forms between species, and the varying relationships those forms may have to one or both species between which they are intermediate.
His experience confirms CD’s view that some species and even some genera of Brachiopoda are consistently more variable than others, and that such variable forms are variable in all localities and at all periods. Similarly a species that shows a lack of variability does so at all points in time and space. Discusses the causes of variability. [See Natural selection, p. 106.]