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Darwin Correspondence Project

From Raphael Meldola   7 June 1871

21 John Street, | Bedford Row W.C

June 7th. 1871

Dear Sir,

Whilst thinking over Natural Selection, of the truth of which I am fully convinced, one or two ideas occurred to me which may possibly be of service to you in future editions of your works. It has often been urged that on the view of evolution the differentiation of the sexes presents a difficulty. This you have satisfactorily answered in the case of phanerogamia but I do not remember having read any explanation for animals. In your work on Orchids you arrive at the conclusion that some great unknown good is derived from the crossing of distinct individuals & it is a well known fact that as an animal advances in organization the different function of the body are carried out by organs specially constructed (using this expression metaphorically) for the purpose.1 Some great & unknown good therefore is derived from this “division of labour” for in the long run the most highly organized species are victorious in the “struggle for existence”. The division of the sexes I would thus refer to the same cause—viz; that some great & unknown good is derived from the “division of labour”:—a species in which fertilization & development were carried out in distinct individuals having advantages over species in which these functions were performed by the same individual.

Then again about the long neck of the giraffe. St. George Mivart argues (Genesis of species) that if the lengthened neck had been produced by periodical famines (as explained in your “Origin”) we ought to find other species of the same order inhabiting the same district with elongated necks also. But his argument is I imagine unsound for on your view, all the species of a genus having descended from a common progenitor & inherited from that progenitor a similar constitution & therefore liability to vary in the same manner when exposed to the same conditions, it is not surprising that no other species of the order has a long neck for the giraffe is the only species of its genus: ordinal relationship having the common progenitor too remote to affect to any extent the constitution of allied genera.2 Indeed the mere fact of the giraffe being the only species of its genus shows that extinction has been largely going on.

At p. 387 Vol. I of your last work (“Descent”) you have stated that both sexes of Hipparchiæ are alike but this is not the case—for in most species the female is more brightly coloured than the male in opposition the usual order of things.3

This however may perhaps be explained in a letter which I published in the same number of “Nature” as that in which you published your reply on Pangenesis to Mr. Galton—(about 6 or 7 weeks ago.)4 I hope you will pardon the liberty which as a stranger I have again taken, but my great devotion to Natural Science is my only excuse.

Yours obediently, | Raphael Meldola. F.C.S

C. Darwin Esq, MA, F.R.S.


In Orchids, p. 359, CD concluded, ‘Nature thus tells us, in the most emphatic manner, that she abhors perpetual self-fertilisation.’
St George Jackson Mivart’s argument about the giraffe appeared in Mivart 1871, pp. 24–9 (for CD’s annotations, see Marginalia 1: 584–8). For CD’s response to Mivart on giraffes, see Origin 6th ed., pp. 177–9. CD did not mention Meldola’s point about the giraffe being the only species in its genus, but did note that competition for ‘browsing on the higher branches’ would be intraspecific (ibid., p. 179).
Meldola refers to the butterfly genus Hipparchia; the common meadow brown butterfly H. janira (now Maniola jurtina) is sexually dimorphic, with males duller and with smaller eyespots than the females.
Meldola’s letter appeared in Nature, 27 April 1871, p. 508. CD’s annotated copy of the page is in DAR 89: 113. Meldola quoted a French article on the mating of butterflies in flight, which noted that in species where the female supported the male during the mating flight, rather than vice versa, the female was the more brightly coloured of the two (Donzel 1836). In Descent 2d ed., p. 319, CD quoted Meldola’s conclusion from Nature. CD’s own letter on Francis Galton’s paper on pangenesis (Galton 1871) appeared in the same issue of Nature, pp. 502–3 (see letter to Nature, [before 27 April 1871]).


Discusses the origin and advantages of sexual differentiation in terms of division of labour.

Discusses the origin of the giraffe’s neck and the unsoundness of St G. J. Mivart’s view with respect to it.

Points out an error in Descent.

Letter details

Letter no.
Raphael Meldola
Charles Robert Darwin
Sent from
London, John St, 21
Source of text
DAR 171: 116
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 7807,” accessed on 26 April 2017,

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