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Darwin Correspondence Project

From Wilhelm Pfeffer1   6 November 1881

Tübingen

6 Nov. 1881

Geehrtester Herr!

Zunächst meinen besten Dank für die Uebersendung Ihrer Photographie die ich mit besonderer Freude meinem Album einverleibt habe.2

Wiesner’s Werk habe ich sogleich nach Erscheinen studirt und bin allerdings’ vielfach nicht mit dessen Auffassung einverstanden, wie ich auch Wiesner mittheilte, der mich um meine Ansicht über sein Buch befragte.3

Für einen fundamentalen Fehler der leider vielfach in der Pflanzenphysiologie gemacht ist und von dem auch meine Erstlingsarbeiten nicht frei sind, halte ich, dass Wiesner die zur mechanischen Ausführung dienenden Vorgänge als unmittelbarste Folgen der von äussern Agentien erzielten Effecte ansieht, während doch thatsächlich dem Erfolge absolut nicht anzusehen ist, welche Kette von Prozessen jene mechanischen Ausführungsvorgänge mit der auslösenden Aktion von Licht, Contact u.s.w. (also mit der direkten Reizwirkung) verknüpft.4

Dutrochet war 1824 (in Recherches sur l. structure intime) in Richtigkeit der Auffassung weiter, als die meisten Botaniker es heute sind und es noch weniger sein würden, wenn nicht durch Ihre Arbeiten die Sensibilität der Pflanzen als ein der animalischen Receptivität analoger Vorgang schärfer hervorgetreten wäre.5

Auch Wiesner’s Deutungen billige ich vielfach nicht. Was speciell die Empfindlichkeit der Wurzelspitze gegen Contact anbelangt, kann ich nach eigenen Erfahrungen nur Ihnen beistimmen und die Versuche in denen die Spitze von zwei Seiten ungleich stark gereizt wird, schliessen die ohnedies gekünstelten Deutungen Wiesner’s aus.6 Ueber die Sensibilität der Wurzelspitze gegen Schwerkraft und Licht stehen mir nicht so ausgedehnte eigene Erfahrungen zu zu Gebote, doch scheint mir in diesen Fällen das Recht mindestens zum grösseren Theile auf Ihrer Seite zu liegen.7

Hinsichtlich der Verknüpfung dieser Receptionsbewegungen mit der Circumnutation weiche ich von Ihrer Auffassung ab.8 Für mich ist Wachsthumsfähigkeit das ursprünglich Gegebene und in der für die Pflanze zweckdienlichen Weise enstanden hieraus autonome (Nutations-) Bewegungen oder Receptionsbewegungen, die überhaupt hinsichtlich der auslösenden Ursache nur darin abweichen, dass in jenen der Anstoss durch im Entwicklungsgang der Pflanze sich einstellende Constellationen gegeben ist, während in den Receptionsbewegungen ein äusseres Agens die auslösende Ursache wird. Damit diese Erfolge hat muss ja aber jedenfalls die Receptivität in der für die Pflanze specifischen Weise erworben sein. Eine solche Erwerbung und damit eine entsprechende Reizbewegung fordern aber nicht, dass die Pflanze autonome Krümmungsbewegungen überhaupt ausbildete und thatsächlich schliesst ja zurücktretende Circumnutation eine besonders ausgebildete Fähigkeit zu Receptionsbewegungen nicht aus. Diese Auffassung habe ich auch im 2 Bande meiner Physiologie vertreten, den ich Ihnen hoffentlich in 3–4 Wochen übersenden kann.9

Die Schwierigkeiten des Verständnisses, welche eine fremde Sprache zu bereiten vermag, weiss ich recht wohl zu würdigen und leider bin ich selbst in der englischen Sprache zu schlecht beschlagen, um Ihnen diese Zeilen in Ihrer Muttersprache zukommen zu lassen. Auch begreife ich wohl, dass meine Darstellungen dem im Deutschen weniger Bewanderten Schwierigkeiten bereitet, besonders wohl, weil ich möglichst knapp zu schreiben pflege und so unvermeidlich zu Satzbildungen komme, in denen das Missverstehen eines einzelnen Wortes für Missverständniss des ganzen Sinnes entscheidend werden kann. Mir liegt es in der That auch durchaus fern Ihnen aus solchen Missverständnissen einen Vorwurf machen zu wollen und kein Mensch wird sich rühmen können, vom derartigen unbewussten Fehlern frei geblieben zu sein.

Nachdem ich durch literarische Studien und meine Dienstpflichten einige Zeit an Ausführung grösserer Experimentaluntersuchungen freue ich mich solche nun wieder mit voller Kraft aufnehmen zu können. Glücklicherweise bin ich jetzt in der Lage ein Institut zur Verfügung zu haben, welches, was Räumlichkeiten, Apparate und Mittel anbelangt alles bietet, was man billigerweise verlangen kann. Vielleicht interessirt Sie zu erfahren, dass das Tübinger Institut, obgleich vor etwa 30 Jahren gebaut, doch immer noch so ziemlich das grösste speziell für Botanik bestimmte Gebäude Deutschland’s ist.10 Jedenfalls macht es H. v. Mohl alle Ehre schon damals so weit blickend die Bedürfnisse später Zeiten vorausgesehen zu haben, und es war mir in der That leicht durch einige bauliche Aenderungen das Institut den heutigen Anforderungen vollkommen anzupassen.11

Mit der Bitte mich Ihrem Herrn Sohn Francis12 bestens zu empfehlen verbleibe ich mit der grössten Hochachtung | Ihr ergebener | Dr W. Pfeffer

[Contemporary translation]

Tübingen. Nov 6. 1881.

1 Most honoured Sir! In the first place receive my thanks for sending me your photograph which I have placed in my Album with especial pleasure.

2 Wiesner’s book I studied as soon as it came out, and certainly I am unable in many respects to agree with his views, as indeed I have informed Wiesner who asked me for my opinion about his book.

3 I consider it a fundamental error in Wiesner to suppose—(and it is an error which has been unfortunately made many times in Vegetable Physiology, & from wh. my own early works are not free) that the processes (Vorgänge) which tend to mechanical working (Ausführung) are direct results (Folgau) of effects (der Effecten) obtained by external agents—whereas, in reality, it is utterly impossible to see from the result (Erfolg) what chain of processes (Prozessen) connects those mechanical workings (Ausführungs Vorgänge) (or working processes) with the releasing (auslösenden) action of light, contact &c—that is, with direct stimulation.

4. Dutrochet was in 1824 nearer the truth than most of the Botanists are now; & they would have been less near than they are, had not the sensibility of plants been sharply marked out, by means of your works, as a process analogous to the receptivity of animals.

5. In many respects too I cannot approve Wiesner’s explanations. As to what specially concerns the sensibility of the root tip to contact, I can, from my own experience only agree with you, and the experiments in which the tip was unequally strongly irritated from two sides exclude the (in any case) artificial explanations of Wiesner. On the subject of the sensibility of the root tip to gravity and light, I have not the advantage of such extended experience of my own, but in these cases the truth seems to me to be on your side at least more (than on his)

6 With regard to the connection between “Receptions bewegungen” (induced movements??) and circumnutation I dissent from your view. In my opinion capacity of growth is the original property (of the plant), and from it arise, in the way most servicible to the Plant, autonomous/automatic (Nutatious) Movements, or (and?) Receptionsbewegungen. These two, with respect to the liberating cause, (auslösenden Ursache) differ only in this: that in the one the impulse is given by means of a “constellationem” (aggregation of conditions??) which come in as the plant develops; whilst in (the other), (the Receptionsbewegungen,) an external agency becomes the releasing cause. In order however that this (this what? this liberating cause?) may have results, receptivity must be acquired after the specific manner of the plant. Such an acquisition, together with a corresponding irritation-movement, does not however require that the Plant should especially develop curved movements, and in fact retrograde circumnutation does not exclude a specially developed capacity for “Receptionsbewegungen”.

This view I have maintained in the second volume of my Physiology, which I hope to be able to send you in three or four weeks.

7. The difficulties in understanding, wh. a foreign language may occasion, I can well appreciate; and unfortunately I am myself too ill equipped in English to send these lines to you in your mother tongue. I can also well understand that my style—to one little conversant with German—may present difficulties,—especially because I try my best to condense, and thus am led to build up sentences in which the misunderstanding of a single word may become at last the misunderstanding of the whole sense. Assuredly it was far from my intention to reproach you with such a misunderstanding, and no one can boast of being free from unconscious errors of that kind.

8 After having been hindered by literary occupations and the duties of my office for some time from carrying out experimental researches on a larger scale, I am glad now again to be able to take up these with my full power. Fortunately I have now the direction of an “Institut” which, as far as regards space, Apparatus and appliances, affords everything that one could reasonably wish for. It may interest you to hear that the Tübingen “Institut”, although built more than 30 years ago, yet remains about the largest building specially intended for Botany in Germany. In any case it is much to the honour of H. v. Mohl that he should have been able to take so wide a view and see in advance the needs of later times; & it was easy for me, by means of some alterations, to adapt perfectly the “Institut” to the necessities of the present time.

9 With the request that you will give my kind regards to your son Francis, I remain, with the greatest respect, yrs truly | Dr. W. Pfeffer

Footnotes

For a translation of this letter, see Appendix I. The contemporary translation is by Camilla Pattrick (see letter to Camilla Pattrick, [after 6 November 1881]).
No letter from CD enclosing a photograph has been found; Pfeffer had sent CD a photograph with his letter of 24 October 1881.
Julius Wiesner’s recent book (Wiesner 1881) was critical of a number of CD’s explanations of plant movement in Movement in plants.
CD had described the effect of light on plants as one of stimulus-response, in which a sensitive part sent a signal to another part, which then moved in response. In contrast, Wiesner believed light acted directly on all affected parts (see letter to Julius Wiesner, 25 October 1881; see also letter to Camilla Pattrick, [after 6 November 1881]).
Henri Dutrochet, in his work on the anatomy and physiology of animals and plants, had maintained that there was no essential difference between plant and animal sensitivity (Dutrochet 1824, pp. 6–7). CD had compared the sensitivity of plants, especially the tip of the radicle, to that of animals in Movement in plants, pp. 543, 573).
CD applied caustic, moisture, bits of card, and thin paper to opposite sides of the tip of the radicle (see Movement in plants, pp. 185, 195).
On the sensitivity of the tip to light and gravity, see Movement in plants, pp. 567–8.
In Movement in plants, pp. 546–8, CD had concluded that the modification of circumnutation led to the acquisition of many beneficial response movements.
For Pfeffer’s views on the cause of plant movement, see Pfeffer 1881, 2: 180; he disagreed with CD’s view that circumnutation was the origin of tropic and nastic movements.
Pfeffer had moved to University of Tübingen in 1878; on the botanical institute, see D. H. Campbell 1888.
Hugo von Mohl had established a botanical laboratory at Tübingen.

Bibliography

Campbell, Douglas H. 1888. The botanical institute at Tübingen. Botanical Gazette 13: 1–4.

Dutrochet, Henri. 1824. Recherches anatomiques et physiologiques sur la structure intime des animaux et les végétaux, et sur leur motilité. Paris: J. B. Baillière.

Movement in plants: The power of movement in plants. By Charles Darwin. Assisted by Francis Darwin. London: John Murray. 1880.

Pfeffer, Wilhelm. 1881. Pflanzenphysiologie. Ein Handbuch des Stoffwechsels und Kraftwechsels in der Pflanze. 2 vols. Leipzig: Wilhelm Engelmann.

Wiesner, Julius. 1881. Das Bewegungsvermögen der Pflanzen. Eine kritische Studie über das gleichnamige Werk von Charles Darwin nebst neuen Untersuchungen. Vienna: Alfred Hölder.

Translation

From Wilhelm Pfeffer1   6 November 1881

Tübingen

6 Nov. 1881

Most honoured Sir!

First, accept my best thanks for sending me your photograph, which I have placed in my album with particular pleasure.2

I studied Wiesner’s work as soon as it appeared, and certainly I am unable in many respects to agree with his views, as indeed I have informed Wiesner, who asked me for my opinion about his book.3

I consider it a fundamental error, which unfortunately is often made in plant physiology and from which my own early works are not free, that Weisner regards the processes that contribute to mechanical explanation as direct effects of external agents—while, in reality, it is utterly impossible to see from the result what chain of events connects those mechanical running processes with the initiating action of light, contact &c—(that is, with direct irritation).4

Dutrochet was in 1824 (in Recherches sur l. structure intime) nearer the correct view than most botanists are now; & they would have been even less so, had not the sensibility of plants been sharply marked out, by means of your works, as a process analogous to the receptivity of animals.5

Moreover, in many respects I cannot endorse Wiesner’s interpretations. As to what specially concerns the sensitivity of the root tip to contact, I can from my own researches agree only with you, and the experiments in which the tip was unequally strongly irritated from two sides rule out the artificial explanations of Wiesner.6 On the sensitivity of the root tip to gravity and light, I have not the advantage of such extended experiments of my own to hand, but in these cases the truth seems to lie at least for the most part on your side.7

Regarding the connection between response movements and circumnutation I dissent from your view.8 For me the capacity for growth is the original property, and from it arise, in the way most serviceable to the plant, autonomous (nutation) movements, or response movements, which actually with respect to the triggering cause, differ only in this: that in one the impulse is given by a combination of factors arising during the course of development; while in response movements an external agency becomes the releasing cause. In order to make this process work, however, responsiveness must be acquired in a manner specific to the plant. Such an acquisition, together with a corresponding irritation movement, does not however require that the plant should specially develop autonomous bending movements, and in fact retrograde circumnutation does not exclude a specially developed capacity for response movements. This view I have maintained in the second volume of my Physiologie, which I hope I will be able to send you in 3–4 weeks.9

The difficulties of comprehension, that a foreign language may occasion, I can well appreciate; and unfortunately I am myself too ill equipped in English to send these lines to you in your mother tongue. I can also well understand that my interpretation, to one less proficient in German, may present difficulties, particularly because I try my best to write as concisely as possible, and thus am led to build up sentences in which the misunderstanding of a single word can result in the misunderstanding of the whole sense. Assuredly it was far from my intention to reproach you from such misunderstandings, and no one could boast of being free from unconscious errors of that kind.

After I by literary occupations and the duties of my office for some time, I rejoice again to be able to take up experimental researches on a larger scale with full vigour. Fortunately I am now in the position of having at my disposal an institute, which, as far as regards space, apparatus and appliances, affords everything that one can reasonably wish for. It may interest you to discover that the Tübingen Institute, although built more than 30 years ago, is still just about the largest building specially intended for botany in Germany.10 In any case it is much to the honour of H. v. Mohl that he should have been able to take so wide a view and see in advance the needs of later times; & it was easy for me, by means of some alterations, to adapt perfectly the “Institut” to the necessities of the present time.11

With the request that you will give my kind regards to your son Francis,12 I remain, with the greatest respect, yrs truly | Dr. W. Pfeffer

Footnotes

For a transcription of this letter in its original German, and a contemporary translation, see Transcript.
No letter from CD enclosing a photograph has been found; Pfeffer had sent CD a photograph with his letter of 24 October 1881.
Julius Wiesner’s recent book (Wiesner 1881) was critical of a number of CD’s explanations of plant movement in Movement in plants.
CD had described the effect of light on plants as one of stimulus-response, in which a sensitive part sent a signal to another part, which then moved in response. In contrast, Wiesner believed light acted directly on all affected parts (see letter to Julius Wiesner, 25 October 1881; see also letter to Camilla Pattrick, [after 6 November 1881]).
Henri Dutrochet, in his work on the anatomy and physiology of animals and plants, had maintained that there was no essential difference between plant and animal sensitivity (Dutrochet 1824, pp. 6–7). CD had compared the sensitivity of plants, especially the tip of the radicle, to that of animals in Movement in plants, pp. 543, 573).
CD applied caustic, moisture, bits of card, and thin paper to opposite sides of the tip of the radicle (see Movement in plants, pp. 185, 195).
On the sensitivity of the tip to light and gravity, see Movement in plants, pp. 567–8.
In Movement in plants, pp. 546–8, CD had concluded that the modification of circumnutation led to the acquisition of many beneficial response movements.
For Pfeffer’s views on the cause of plant movement, see Pfeffer 1881, 2: 180; he disagreed with CD’s view that circumnutation was the origin of tropic and nastic movements.
Pfeffer had moved to University of Tübingen in 1878; on the botanical institute, see D. H. Campbell 1888.
Hugo von Mohl had established a botanical laboratory at Tübingen.

Bibliography

Campbell, Douglas H. 1888. The botanical institute at Tübingen. Botanical Gazette 13: 1–4.

Dutrochet, Henri. 1824. Recherches anatomiques et physiologiques sur la structure intime des animaux et les végétaux, et sur leur motilité. Paris: J. B. Baillière.

Movement in plants: The power of movement in plants. By Charles Darwin. Assisted by Francis Darwin. London: John Murray. 1880.

Pfeffer, Wilhelm. 1881. Pflanzenphysiologie. Ein Handbuch des Stoffwechsels und Kraftwechsels in der Pflanze. 2 vols. Leipzig: Wilhelm Engelmann.

Wiesner, Julius. 1881. Das Bewegungsvermögen der Pflanzen. Eine kritische Studie über das gleichnamige Werk von Charles Darwin nebst neuen Untersuchungen. Vienna: Alfred Hölder.

Summary

It is impossible to trace the direct connections between stimuli and responses in plant movements. Disagrees with much of Julius von Wiesner [Die Bewegungsvermögen der Pflanzen (1881)]. Disagrees with CD on induced movements and circumnutation.

Letter details

Letter no.
DCP-LETT-13464
From
Wilhelm Friedrich Philipp (Wilhelm) Pfeffer
To
Charles Robert Darwin
Sent from
Tübingen
Source of text
DAR 174: 39
Physical description
ALS 5pp

Please cite as

Darwin Correspondence Project, “Letter no. 13464,” accessed on 28 March 2024, https://www.darwinproject.ac.uk/letter/?docId=letters/DCP-LETT-13464.xml

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