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Darwin Correspondence Project

To James Paget   14 November 1880

Down, Beckenham, Kent. | Railway Station | Orpington. S.E.R.

November 14th 1880

My dear Paget

I am very much obliged for your essay which has interested me greatly.1 What indomitable activity you have! It is a surprising thought that the diseases of plants shd. illustrate human pathology. I have the German Encyclopædia & a few weeks ago told my son Francis that the article on the diseases of Plants would be well worth his study, but I did not know that it was written by Dr Frank, for whom I entertain a high respect, as a first-rate observer & experimentiser, though for some unknown reason he has been a good deal snubbed in Germany.2

I can give you one good case of regrowth in plants, recently often observed by me, though only externally, as I do not know enough of histology to follow out details. It is the tip of the radicle of a germinating common bean. The case is remarkable in some respects, for the tip is sensitive to various stimuli & transmits an order, causing the upper part of the radicle to bend. When the tip (for a length of about 1mm) is cut transversely off the radicle is not acted on by gravitation or other irritants, such as contact &c &c, but a new tip is regenerated in from 2 to 4 days, & then the radicle is again acted on by gravitation & will bend to centre of earth. The tip of the radicle is a kind of brain to the whole growing part of the radicle.3

My observation will be published in about a weeks time, & I wd have sent you the book, but I do not suppose that there is anything else in the book which would interest you.—4

I am delighted that you have drawn attention to galls.5 They have always seemed to me profoundly interesting. Many years ago I began (but failed for want of time, strength & health, as on infinitely many other occasions) to experimentise on plants, by injecting into their tissues, some alkaloids. & the poison of wasps, to see if I could make anything like galls. If I remember rightly in a few cases the tissues were thickened & hardened. I began those experiments, because if by different poisons I could have affected slightly & differently the tissues of the same plant, I thought there wd be no insuperable difficulty in the fittest poisons being developed by insects so as to produce galls adapted for them.6 Every character, as far as I can see, is apt to vary. Judging from one of your sentences you will smile at this.—7

To anyone believing in my Pangenesis (if such a man exists) there does not seem to me any extreme difficulty in understanding why plants have such little power of regeneration; for there is reason to think that my imaginary gemmules have small power of passing from cell to cell.—8

Forgive me for scribbling at such unreasonable length; but you are to blame from having interested me so much.—

My dear Paget | Yours very sincerely | Ch. Darwin

P.S. | Perhaps you may remember that some 2 years ago you asked me to lunch with you & proposed that I shd offer myself again, whenever I next come to London, I will do so, & thus have the pleasure of seeing you.—

Footnotes

Paget had cited an article by Albert Bernhard Frank from Encyklopädie der Naturwissenschaften vol. 4, Die Pflanzenkrankheiten (see Paget 1880, pp. 611 n. and 613 n.); CD’s copy of the Encyklopädie is in the Darwin Library–Down. CD cited Frank 1868 and Frank 1870 in Movement in plants. Francis Darwin had remarked on Frank’s career difficulties in his letter of 29 May 1879 (Correspondence vol. 27).
CD experimented on the regrowth and bending of the tip or apex of the radical in Vicia faba (broad or fava bean) after amputation and the application of caustic (see Movement in plants, pp. 524–37). On the tip of the radical as analogous to the ‘brain’ of lower animals, see ibid., p. 573.
Paget’s name does not appear on the presentation list for Movement in plants (see Appendix IV).
Paget compared galls to inflammation and morbid growths in animal tissue, such as cysts, tumours, and cancers (see Paget 1880, pp. 649–51).
For CD’s interest in galls and gall-making insects, see Variation 2: 282–5. In 1864, he suggested an experiment involving the insertion of poisons from insects and snakes, and other chemical compounds into plant tissues (see Correspondence vol. 12, letter to B. D. Walsh, 21 October [1864] and n. 6, and Correspondence vol. 13, letter to B. D. Walsh, 27 March [1865]).
While noting the great variety of galls and gall-making insects, Paget also remarked on the specificity and constancy of each form: And the whole process of the plant, though it be one of disease and, in a sense, unnatural, is yet so regular, so constant and specific, that the form and other characters of each gall or other morbid product are, usually, as constant and characteristic as are those of the insect itself. (Paget 1880, p. 650.)
On CD’s hypothesis of pangenesis and the role of gemmules, see Variation 2: 374–7; he cited Paget’s claim that the reparative power in organisms was the same as the power of growth in ibid., p. 359. CD remarked on the possibility of gemmules passing through cell walls in his letter to Nature, [before 27 April 1871] (Correspondence vol. 19).

Bibliography

Frank, Albert Bernhard. 1868. Beiträge zur Pflanzenphysiologie. Leipzig: Wilhelm Engelmann.

Frank, Albert Bernhard. 1870. Die natürliche wagerechte Richtung von Pflanzentheilen und ihre Abhängigkeit vom Lichte und von der Gravitation. Leipzig: Weissbach.

Paget, James. 1880. An address on elemental pathology. British Medical Journal 2: 611–14, 649–52.

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

Summary

Surprising thought that diseases of plants should illustrate human pathology.

Will recommend A. B. Frank’s article in a German encyclopedia, on diseases of plants, to Francis Darwin.

Gives JP a good case of regeneration in plants – the radicle of the common bean. That plants have little power of regeneration is not difficult to understand by anyone who believes in Pangenesis, "if such a man exists … There is reason to think that my imaginary gemmules have small power of passing from cell to cell."

Refers to early experiments in which he tried to produce galls in plants by injecting poisons.

Letter details

Letter no.
DCP-LETT-12819
From
Charles Robert Darwin
To
James Paget, 1st baronet
Sent from
Down
Source of text
Wellcome Collection (MS.5703/31)
Physical description
ALS 8pp

Please cite as

Darwin Correspondence Project, “Letter no. 12819,” accessed on 25 February 2024, https://www.darwinproject.ac.uk/letter/?docId=letters/DCP-LETT-12819.xml

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