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Darwin Correspondence Project

From Francis Darwin   [before 31 July 1879]1

Bot Institut | Würzburg

My dear Father,

Just after I wrote last Sachs asked me if I should like to publish my root work in his Arbeiten so of of course I said I should like it.2 It is nice to publish with the other people who have been working with me here & there is also honour and glory. It is rather difficult to write as I must not quote the last edition even of the Lehrbuch as there Sachs evidently expected negatively heliotropic roots to grow quicker in light.3 I am glad to discover that he has not been quite so much of a weather cock as I thought as in 1876 his pupil Müller Thurgau published what is pretty well the general idea which we have namely that Heliotropism is not the direct result of the shaded side being obliged to grow quicker but that heliotropism & geotropism are both “Reizerscheinungen”4   In his lectures this summer he has said the same thing distinctly—that the light or gravity acting in an unusual direction acts like a Reiz and the plant’s internal organisn. determines what kind of movement shall follow. When Müller Thurgau wrote his paper he quoted what was merely Sachs opinion as if it had been published so that I asked Sachs where he had published this view about Heliotropism. I thought the simplest thing in quoting was to speak of “Müllers investigations in the Lab at Wzbg”: but Sachs wants me to put some such phrase as “The question which Sachs laid before Müller for investigation in the Lab at Wzbg”. Müllers way of putting it is certainly misleading so I suppose I must say something of the kind5

He also wanted me to criticise Wiesner, & I was preparing to say I would see him blowed when he took it into his head he would do it himself, which is a relief.6 Sachs says he will translate my paper for the Arbeiten into German himself as it is so short. It is usually called purgatory here when an MS has been given to Sachs & until it is quite approved of. Elving the Finn has had an awful dose of purgatory, Sachs wants him to bring in his favourite idea of an organ which grows horizontally really consisting of a positive & negatively geotropic organ tied together, & a lot of other schematic things. Elving and everybody here thinks it pure bosh, & he is trying to bring it to absurdity by inventing more & more such theories & drawing them on the black board & showing them to Sachs; anyhow he says he won’t alter his MS in this respect.7 I produced the theory that when a man stands still he only does so because he really consists of two men walking equally quick in opposite directions, which met with much applause from the simple German mind

I shall start on Thursday pm & go by Heidelberg & Strassburg. I want to get one or two things at the instrument maker at Heidelberg & then Strassburg is so close that I should like to go & see De Bary & Co for one day.8 I shall be able to get to London by Sunday sometime I hope & so on. I suppose of course Ubbadubba goes with you when you go? If you want me to look at the life of Eras I shall call at Uncle Ras so any message would find me there.9 I have made two appeals to the public to know how the dickens to get to Coniston. I can do the French life quite well.10


The date is established by Francis’s reference to starting his return to England on Thursday (see n. 9, below). In 1879, the Thursday before 4 August was 31 July.
The latest extant letter from Francis is that of 9 July 1879. Francis had been uncertain whether he would be asked to publish his work in Julius Sachs’s journal, Arbeiten des botanischen Instituts in Würzburg (see letter from Francis Darwin, 4 July 1879). Francis’s 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) appeared in 1880.
See letter from Francis Darwin, 4 July 1879 and n. 7. In his published paper (F. Darwin 1880, p. 522), Francis referred to unpublished work of Alexander Wolkoff and the last (fourth) edition of Sachs’s Lehrbuch der Botanik (Textbook of botany; Sachs 1874, pp. 804, 810).
Hermann Müller-Thurgau, in his article ‘Ueber Heliotropismus’ (Müller-Thurgau 1876, pp. 88–9), had shown that the bending of a stem towards a horizontal light source continued for some time even after the light was removed. Reizerscheinungen: stimulus phenomena (German).
In the introduction to his article on heliotropism (Müller-Thurgau 1876, p. 66), Müller-Thurgau had noted that his research, conducted over two summers at Würzburg, was intended to show the relationship between the light source and bending of the stems, as Sachs had done in experiments on geotropism. Most of his references to Sachs relate to the latter’s research on geotropism (Sachs 1873b, Sachs 1873–4).
The first part of Julius Wiesner’s monograph on heliotropic phenomena had appeared in 1878 (Wiesner 1878–80). For Sachs’s negative view of Wiesner’s work, see the letter from Francis Darwin, 29 May 1879 and n. 8.
Fredrik Elfving had observed a tendency in roots of the genus Scirpus (bulrushes) to grow horizontally (see letter from Francis Darwin, [after 2 June 1879] and n. 3).
The instrument maker in Heidelberg has not been identified. Anton de Bary was professor of botany at Straßburg (Strasbourg), which is about seventy miles south-west of Heidelberg.
Francis joined the Darwins in the Lake District on 4 August 1879 (Emma Darwin’s diary (DAR 242)); the Sunday before that was 3 August. He stopped at Erasmus Alvey Darwin’s London residence; Erasmus had a copy of CD’s proof-sheets of the first version of his introductory essay on Erasmus Darwin, the first part of Erasmus Darwin. Ubbadubba was a pet name for Francis’s son, Bernard Darwin.
The Darwins stayed at Coniston in the Lake District from 2 to 27 August 1879 (Emma Darwin’s diary (DAR 242)). The ‘French life’ is probably a reference to the biography of Erasmus Darwin published in Biographie médicale (see letter from James Paget, 25 July 1879 and n. 1).


Biographie médicale: Dictionnaire des sciences médicales. Biographie médicale. Edited by Antoine-Jacques-Louis Jourdan. 7 vols. Paris: C. L. F. Panckoucke. 1820–5.

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.

Erasmus Darwin. By Ernst Krause. Translated from the German by W. S. Dallas, with a preliminary notice by Charles Darwin. London: John Murray. 1879.

Müller-Thurgau, Hermann. 1876. Ueber Heliotropismus. Flora 59: 65–70, 88–95.

Sachs, Julius. 1873–4. Ueber das Wachsthum der Haupt- und Nebenwurzeln. Arbeiten des Botanischen Instituts in Würzburg 1 (1871–4): 385–474, 584–634.

Sachs, Julius. 1873b. Ueber Wachsthum und Geotropismus aufrechter Stengel. Flora 56: 321–31

Sachs, Julius. 1874b. Lehrbuch der Botanik nach dem gegenwärtigen Stand der Wissenschaft. 4th edition. Leipzig: W. Engelmann.

Wiesner, Julius. 1878–80. Die heliotropischen Erscheinungen im Pflanzenreiche. [Read 4 July 1878 and 18 March 1880.] Denkschriften der kaiserlichen Akademie der Wissenschaften, mathematisch-naturwissenschaftliche Classe 39 (1879) pt. 1: 143–209; 42 (1880) pt. 1: 1–92.


Discusses Müller-Thurgau’s work on heliotropism. Will start on Thursday for Heidelberg and Strassburg.

Letter details

Letter no.
Francis Darwin
Charles Robert Darwin
Sent from
Source of text
DAR 274.1: 56
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 12177F,” accessed on 23 May 2022,