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Darwin Correspondence Project

From Francis Darwin   4 July 1879

Bot Institut | Würzburg

Friday July 4/79

Please ask G to order a copy of “Shakespeare’s C Merry Tales” to be sent to me here. I am not sure of the title— The German Humour man wants to see them1

My dear Father

Goebel says they ought strictly to be Prosheliism & Apheliism but he thinks there would be no harm in ‘helism’ with one i.2 The air roots of Monstera didn’t give any definite results none of them turned well but the best one was one with un-greased gold B’s skin3   I see from my notes about mustard roots in the winter, that caustic decidedly stopped aphelism the non-caustic ones all bending. I will try it here again. I sow mustard nearly every day now to have a stock for measuring— I have confirmed the fact that mustard roots grow quicker in darkness, by marking them at 10 mm in the am & measuring in evening as before.4 Now I have also mustard on a revolving disc & I measure the growth with a microscope like Vines did the mould & I think it will give neat results.5 I am also doing air roots of Chlorophytum (which I have cultivated in Nährstofflösung) with a microscope. And I shall tomorrow begin measuring the growing shoots of Tecoma radicans with are well (as you were)—aphelic. I have rigged up a tent to keep sun off & have got a dark & light bell &c all ready fitted to put together. If I can do that & the stems of Tropæolum I shall have enough for a decent paper.6 I quite agree with you that it is well worth while to prove that negative heliotropic things grow quicker in darkness. I am pleased that I have succeeded with mustard roots quite against Sach’s advice; first he said O they weren’t regularly aphelic, it was only a “pathologische Erscheinung”, & then “O you’ll never make out a difference in the growth of roots in light & dark   Wolkoff worked very industriously at it & couldn’t succeed” I don’t know whether he will ask me to publish it in his Arbeiten & now I don’t care.7 I see it is a very good thing to be as independent of him as possible. I came to this conclusion before I heard about De Vries. Stahl works entirely in his own room, though many things he could do much better here, simply because he cannot stand being under Sachs in any way. He is very anxious to keep on perfect terms with Sachs & he finds the best way is only to see him when he (Stahl) is not working   Stahl says he thinks it absolutely bad for anyone to work under Sachs unless they are of an independent nature8 I think you had better not repeat anything about Sachs and Stahl as I see Stahl is very cautious—for instance he said to me “Tell Ward (the Englishman) he ought to work under De Bary, he would do much better there, only don’t say I said so”9

One day I observed the movements of Oscillaria, which are Algæ consisting of a row of cells, and which move about by a serpentine squirming movement; they also make the most perfect circumnutation, each circle in about 40″10 It is very pretty to see the tip bend over before the return movement begins. If A & B represent the two extreme ends of a nutation, diagram then when it has moved from B to A and is going to return, the tip bends first as (a) & then the whole filament swings over. Stahl believes this goes on by a change of tension without growth. I have had

CD annotations

0.3 Please … see them 0.4] crossed ink
1.1 Goebel … results 1.3] double scored red crayon
2.7 If … growth. 2.13] scored red crayon


George Howard Darwin would probably have ordered a copy of Shakespeare’s jest book. A hundred mery talys, from the only perfect copy known (Oesterley ed. 1866). The title of the work alludes to a line in William Shakespeare’s Much ado about nothing (2.1) that refers to ‘the 100 Merry Tales’, a collection of humorous anecdotes. The edited volume used a version of the collection discovered in the Royal Library of the University of Göttingen (Oesterley ed. 1866, p. iii). Francis’s German friend has not been identified.
Karl Goebel, a colleague of Francis’s at Würzburg with a background in classical languages, had been advising Francis on CD’s proposed terms for motion towards and away from the sun (see letter from Francis Darwin, [after 16 June 1879], and letter to Francis Darwin, 25 June [1879]).
See letter from Francis Darwin to Emma Darwin, 30 June 1879 and n. 5. Francis was covering tips of aerial roots with gold-beater’s skin to determine whether the apex controlled the response to light in the root. Monstera is a genus in the family Araceae (arums).
In his recent experiments with Sinapis alba (white mustard), Francis noted that the roots were strongly apheliotropic and that they grew much quicker in darkness (letter from Francis Darwin, [after 16 June 1879] and n. 4).
On Sydney Howard Vines’s use of a micro-telescope to measure growth, see the letter from Francis Darwin, [before 26 June 1879] and n. 7.
CD was also studying aerial roots and had received a plant of Chlorophytum orchidastrum (fireflash or orange spider plant; family Asparagaceae) from Kew (letter to W. T. Thiselton-Dyer, 5 June 1879 and n. 2). Nährstofflösung: nutrient solution (German). Tecoma radicans (a synonym of Campsis radicans) is trumpet creeper (family Bignoniaceae); Tropaeolum is the genus of nasturtiums (family Geraniaceae).
See n. 4, above. Pathologische Erscheinung: pathological phenomenon (German). Alexander Wolkoff’s unpublished research on the action of light on negatively heliotropic organs had been described by Julius Sachs in his Text-book of botany (Sachs 1875, pp. 756–7). In the event, Francis did publish his paper ‘Über das Wachstum negativ heliotropischer Wurzeln im Licht und im Finstern’ (On the growth of negatively heliotropic roots in light and in shade; F. Darwin 1880) in Sachs’s journal, Arbeiten des botanischen Instituts in Würzburg.
Hugo de Vries was professor extraordinarius of botany at Amsterdam, but still spent summers at the laboratory of Julius Sachs in Würzburg. He had been visiting the laboratory since 1871 and had worked there full-time from 1875 to 1877, writing a series of monographs for the Prussian ministry of agriculture, a position obtained for him by Sachs (Berkel et al. 1999, p. 155). Ernst Stahl had been Sachs’s assistant from 1874 until 1877 (NDB).
Harry Marshall Ward was a student at Cambridge University. He worked in Sachs’s laboratory in 1880 and in the laboratory of Anton de Bary in Straßburg (Strasbourg) in 1882.
Francis evidently refers to the genus of blue-green algae, Oscillatoria; it is now classified within the bacterial phylum Cyanobacteria, rather than as a plant. Filaments made up of rows of cells form colonies; these colonies can orient themselves to face the light by means of individual filaments moving against each other.


Berkel, Klaas van, et al. 1999. A history of science in the Netherlands: survey, themes, and reference. Leiden: Brill.

Darwin, Francis. 1880b. Über das Wachsthum negativ heliotropischer Wurzeln im Licht und im Finstern. Arbeiten des botanischen Instituts in Würzburg 2 (1878–82): 521–8.

NDB: Neue deutsche Biographie. Under the auspices of the Historical Commission of the Bavarian Academy of Sciences. 27 vols. (A–Wettiner) to date. Berlin: Duncker & Humblot. 1953–.

Oesterley, Herman, ed. 1866. Shakespeare’s jest book. A hundred mery talys, from the only perfect copy known. London: John Russell Smith.

Sachs, Julius. 1875a. Text-book of botany: morphological and physiological. Translated and annotated by Alfred W. Bennett, assisted by W. T. Thiselton-Dyer. Oxford: Clarendon Press.


Heliotropism nomenclature. Apheliotropic mustard roots grow more quickly in dark. Measures growth with microscope as S. H. Vines did in mould. Studying air roots.

FD’s and Stahl’s negative opinion of Sachs.

Letter details

Letter no.
Francis Darwin
Charles Robert Darwin
Sent from
Source of text
DAR 209.3: 334
Physical description
AL 4pp †

Please cite as

Darwin Correspondence Project, “Letter no. 12134,” accessed on 13 September 2023,