# To W. B. Tegetmeier   19 February [1863]

Down Bromley Kent

Feb. 19th.

My dear Sir

I am delighted to hear that you have the Fowls:1 as soon as you have chickens you could kill off the old Birds. I shd. think the 3 ample.— It would be better to cross some cocks & Hens of the half-breds from the two nests; so as not to cross full brother & sister. I have not much hope that they will be partly or wholly sterile, yet after what happened to me, I shd. never have been easy without a trial.—2

I suggested Turbits, because statements have been published that they are sometimes sterile with other breeds, & I mentioned Carriers, merely as a very distinct breed.3 I thought Barbs & Fantails bad solely because I had made several crosses & found the $\frac{1}{2}$ breds perfectly fertile,—even brother & sister together. Did I send you (I cannot remember) a M.S. list of crosses; if so for Heaven sake return it.—4 I get slowly on with my work; but am never idle.—5

I much wish I could have seen you at Linn. Soc; but I was that day very unwell.—6 Pray do not forget to ask Poultry & Pigeon men (especially latter) whether they have ever matched two birds (for instance two almonds, Tumblers) & could not get them to breed, but afterwards found that both birds would breed when otherwise matched.—7

I hope the world goes pretty well with you.—

My dear Sir | Yours sincerely | C. Darwin

## Footnotes

Tegetmeier was about to conduct crossing experiments for CD and had informed him that Silk hens and a Spanish cock had been acquired for the trials (see letter from W. B. Tegetmeier, 18 February 1863 and n. 3, and Correspondence vol. 10, letter to W. B. Tegetmeier, 27 [December 1862]).
In his letter of 18 February 1863, Tegetmeier asked CD for details of how to proceed with his crossing experiments (see n. 1, above). CD had previously conducted the cross that Tegetmeier was about to undertake, between a Spanish cock and a White Silk hen (see CD’s Experimental notebook (DAR 157a), pp. 41–2, 49–50). The result of the experiment, carried out in 1859 and 1860, was the production of ‘plenty of eggs & chickens; but two of these seemed to be quite sterile’ (see Correspondence vol. 10, letter to W. B. Tegetmeier, 27 [December 1862]). CD added that at the time he was ‘sadly overdone’ with work, continuing: ‘but [I] have ever since much reproached myself, that I did not preserve & carefully test the procre[a]tive power of these hens’.
In his letter of 18 February 1863, Tegetmeier asked CD if he would explain his suggestion that it would be better ‘to employ Carriers and Turbits, instead of Barbs and Fantails’. The supposed sterility of turbits when crossed with other breeds of pigeon is discussed in Variation 1: 192 n. 19. CD cited Temminck 1813–15 and Riedel 1824 as sources of this information. An annotated copy of Riedel 1824 is preserved in the Darwin Library–CUL (see Marginalia 1: 708–10).
In his letter of 27 [December 1862] (Correspondence vol. 10), CD sent Tegetmeier a manuscript list of the crosses he and others had made with different pigeon varieties. The manuscript has not been found; however, see Variation 1: 192 n. 19.
CD refers to Variation, which was published in two volumes in 1868. CD had been engaged in writing a draft of the three chapters on inheritance since 23 January 1863 (Variation 2: 1–84); he completed the work on 1 April (see ‘Journal’ (Correspondence vol. 11, Appendix II)).
See letter from W. B. Tegetmeier, 18 February 1863; CD refers to the meeting of the Linnean Society on 5 February at which his paper ‘Two forms in species of Linum’ was read. CD was in London from 4 to 14 February 1863 (see ‘Journal’ (Correspondence vol. 11, Appendix II)).
See Correspondence vol. 10, letter to W. B. Tegetmeier, 27 [December 1862]. CD was anxious to find a case of ‘two birds which when paired were unproductive, yet neither impotent’, in an attempt to ‘make two strains, both fertile, & yet sterile when one of one strain is crossed with one of the other strain’ (Correspondence vol. 10, letter to T. H. Huxley, 28 December [1862]). This formed part of CD’s search for experimental evidence to answer Thomas Henry Huxley’s criticism of the theory of natural selection. Huxley had argued that natural selection could never be considered a vera causa for the origin of species until artificial selection had been shown to be capable of producing varieties of a species that were cross-sterile (see [T. H. Huxley] 1860, and Correspondence vol. 10, Appendix VI).

## Summary

Discusses experiments that WBT will undertake to investigate whether particular pigeon and poultry crosses produce sterile hybrids.

## Letter details

Letter no.
DCP-LETT-3998
From
Charles Robert Darwin
To
William Bernhard Tegetmeier
Sent from
Down
Source of text
Archives of the New York Botanical Garden (Charles Finney Cox collection, Tegetmeier ser. 1: 27)
Physical description
4pp

Darwin Correspondence Project, “Letter no. 3998,” accessed on 18 July 2019, https://www.darwinproject.ac.uk/letter/DCP-LETT-3998.xml

Also published in The Correspondence of Charles Darwin, vol. 11

letter