From H. B. Dobell 6 October 1871
84, Harley Street, | Cavendish Square, W.
Oct 6 1871
Dear Mr Darwin
An idea has occurred to me with reference to Species, which my knowledge is insufficient to test. It may be of great value or none, and as I have never seen it suggested before, I feel that my best plan is to communicate it to you, who will, at once, be able to test its truth & estimate its importance, and if it of any value you will, I know, give me the full credit of the suggestion.—
—It is this, that the distinctive mark of species may be the duration of pregnancy, incubation, or germination, under identical conditions of life.1
So far as I am aware the average duration of pregnancy is quite independent of external conditions of life; with eggs & seeds I believe it is different & in these the test is not so easily applied, but still it might be effected by artificially securing identical conditions.
As I said before, my knowledge is too limited to allow me to test the value of the idea and I therefore convey it to you in case it should be worth anything.
Believe me | Yours truly | Horace Dobell
Ch. Darwin Esq | &c
Footnotes
Bibliography
Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 29 vols to date. Cambridge: Cambridge University Press. 1985–.
Origin: On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. By Charles Darwin. London: John Murray. 1859.
Summary
Asks CD’s opinion of his suggestion that a distinctive mark of species may be the duration of pregnancy, incubation, or germination.
Letter details
- Letter no.
- DCP-LETT-7989
- From
- Horace Benge Dobell
- To
- Charles Robert Darwin
- Sent from
- London, Harley St, 84
- Source of text
- DAR 162: 191
- Physical description
- ALS 3pp
Please cite as
Darwin Correspondence Project, “Letter no. 7989,” accessed on 25 April 2024, https://www.darwinproject.ac.uk/letter/?docId=letters/DCP-LETT-7989.xml
Also published in The Correspondence of Charles Darwin, vol. 19