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Darwin Correspondence Project

To Raphael Meldola   9 June [1871]

Down, | Beckenham, Kent.

June 9th

Dear Sir

I am greatly obliged by your note.1 I have read with much interest & carefully perused your letter in Nature, & am looking out for a paper announced for Linn. Soc.— Your remarks shall all be in due time fully considered.2 With respect to the separation of the sexes, I have often reflected on the subject; but there is much difficulty, as it seems to me & as Nägeli has insisted, in as much as a strong case can be made out in favour of the view that with plants at least the sexes were primordially distinct, then became in many cases united, & in not a few cases reseparated.3 I have during the last 5 or 6 years been making a most laborious series of experiments, by which I shall be able, I think, to demonstrate the wonderful good derived from crossing, & I am almost sure but shall not know till the end of the summer that I shall be able to prove that the good is precisely of the same kind which the adult individual derives from slight changes of conditions.—4

With very sincere thanks for your interest in my work, I remain | Dear Sir | Yours very faithfully | Ch. Darwin


See letter from Raphael Meldola, 7 June 1871. Carl Wilhelm von Nägeli discussed the development of plant sexuality in Nägeli 1865, pp. 20–5.
CD refers to his experiments growing several generations of cross- and self-fertilised plants. The results were published in Cross and self fertilisation.


Cross and self fertilisation: The effects of cross and self fertilisation in the vegetable kingdom. By Charles Darwin. London: John Murray. 1876.

Nägeli, Carl Wilhelm von. 1865. Entstehung und Begriff der naturhistorischen Art. 2d edition. Munich: Verlag der königl. Akademie.


Mentions the difficulties in explaining the separation of sexes and Carl Nägeli’s view that the sexes of plants were primordially distinct.

Has been experimenting for five or six years to demonstrate that the benefits of crossing are the same as those derived from a slight change of conditions.

Letter details

Letter no.
Charles Robert Darwin
Raphael Meldola
Sent from
JU 9 71
Source of text
Oxford University Museum of Natural History (Hope Entomological Collections 1350: Hope/Westwood Archive, Darwin folder)
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 7813,” accessed on 28 March 2020,

Also published in The Correspondence of Charles Darwin, vol. 19