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Darwin Correspondence Project

To C. G. Semper   [after 6 December 1878]1

You are perfectly willing for you use my letters in any way you think fit & I am heartily glad you are going to take up the subject whether or not you oppose the conclusion at which I have arrived.—2

I sh like to add a sentence or two to what I remarked about the [extreme caution], as it seems to me, necessary before we say that some [structure] is morphologic (to [use] Nageli [paper]

We ought surely to bear in mind the indirect consequence of some change or [alt] which is beneficial. For instance the case malformation [locules] of the [Placenta] (which Nägeli admits as a morpholog feat)3

Wonderfully you write with Machine4

Saporta & Neumayr.

Huxley [illeg].—5 | I utterly disbelieve in innate tendency to vary & [illeg] ([illeg]) quite independently of conditions, & then [agree] in the [next] [illeg] that every variation whether wholly inherited or not [illeg] is [due] to external conditions.—6


The date is established by the relationship between this letter and the letter from C. G. Semper, 6 December 1878.
See letter from C. G. Semper, 6 December 1878 and n. 2. After this passage, CD crossed out a section of text which reads: Excert | Far from valueless— when I wrote the Origin I cd find no evidence, & pray remember how much has been altered since then | In my Variation of An & Plants I gave one case & now could give very many more— My observations of plants have *led me to believe [above del ‘convinced’] me that astonishingly small differences are effective & a year ago I began to set to work to prove this experimentally, but I had too much other work in hand & too old & not strong enough The case referred to has not been identified; Variation was published in 1868, nine years after the first edition of Origin.
Carl Wilhelm von Nägeli had distinguished what he called purely morphological features from physiological features, claiming that only the latter were subject to natural selection, while changes in the former could be accounted for by his ‘perfectibility principle’ (Vervollkommnungsprincip; Nägeli 1865, pp. 27–30). The type of placentation is often used as a character to differentiate flowering plant families, so was considered a ‘purely morphological’ feature by Nägeli. In response to Nägeli 1865, CD gave examples of variation in placentation and number of ovaries in plants of the same species in Origin 5th ed., pp. 155–6.
Semper’s letter of 6 December 1878 was typewritten.
Gaston de Saporta, Melchior Neumayr, and Thomas Henry Huxley.
CD had responded to Nägeli’s critique in Origin 5th ed., p. 151 (see also Correspondence vol. 14, letter to C. W. von Nägeli, 12 June [1866], and letter to J. V. Carus, 21 November 1866).


Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 27 vols to date. Cambridge: Cambridge University Press. 1985–.

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

Origin 5th ed.: On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. 5th edition, with additions and corrections. By Charles Darwin. London: John Murray. 1869.

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.

Variation: The variation of animals and plants under domestication. By Charles Darwin. 2 vols. London: John Murray. 1868.


Gives CGS permission to use his letters in any way he thinks fit.

Discusses the direct effect of external conditions as an agent of change in organisms; has encountered many cases since the publication of Origin.

Letter details

Letter no.
Charles Robert Darwin
Carl Gottfried Semper
Sent from
Source of text
DAR 202: 120v
Physical description
ADraft 1p (on 11776)

Please cite as

Darwin Correspondence Project, “Letter no. 11777,” accessed on 16 June 2021,