skip to content

Darwin Correspondence Project

To James Torbitt   14 April 1876


Apr. 14, 1876.

My dear Sir,

Prof. Ansted’s letter which I return, is a very good one.1 The more I reflect on your scheme the more I believe it is the one plan for succeeding in getting a sound variety.2

During the last 10 years I have been experimenting on crossing plants and shall publish the results in the autumn. The flowers of the genus Solanum do not produce nectar and are but little visited by insects, tho’ I have seen some on the flowers of the potato. Nevertheless they probably do not get intercrossed so much as the flowers of most other plants.3 Therefore I would strongly advise you to intercross any two varieties, (and the more they differ in all respects the better) that is if you can get two varieties which are moderately free of the pest. I know that there is the strongest probability that seedlings raised from a cross of this kind would not only grow more vigorously, but would possess greater constitutional vigour, so as to be less liable to disease of all kind and death.

Hoping that you may be successful | I remain, my dear Sir | Yours faithfully | Ch. Darwin.


See letter from James Torbitt, 12 April 1876. The letter from David Thomas Ansted to Torbitt has not been found.
Torbitt’s scheme for growing potatoes from seed and preserving the seeds of disease-resistant plants from each generation is explained in Torbitt 1876.
Cross and self fertilisation was published on 10 November 1876 (Freeman 1977). Solanum is the large genus of flowering plants that includes the potato (S. tuberosum). In ibid., pp. 387–8 n., CD expressed regret that he had not experimented on plants with inconspicuous flowers that were only occasionally visited by insects, like some species of Solanum. He noted that the potato had more conspicuous flowers than other Solanum species that did not secrete nectar and were seldom visited by insects. He added: ‘some of the varieties did not bear seed when fertilised with pollen from the same variety, but were fertile with that from another variety.’


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

Freeman, Richard Broke. 1977. The works of Charles Darwin: an annotated bibliographical handlist. 2d edition. Folkestone, Kent: William Dawson & Sons. Hamden, Conn.: Archon Books, Shoe String Press.

Torbitt, James. 1876. Cras credemus. A treatise on the cultivation of the potato from the seed, having for proposed results the extinction of the disease, and a yield of thirty, forty or more tons of tubers per statute acre. (Sent, accompanied by a packet of seed, to each member of the House of Lords; each member of the House of Commons; and the principal landlords of Ulster.) Belfast: printed by Alexander Mayne.


Gives advice on breeding of blight-resistant potatoes.

Letter details

Letter no.
Charles Robert Darwin
James Torbitt
Sent from
Source of text
DAR 148: 93
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 10451,” accessed on 14 August 2020,

Also published in The Correspondence of Charles Darwin, vol. 24