To Francis Darwin 30 [May 1876]1
Hopedene
Monday 30th
My dear F.
You cd. make aggregation less intense by using much weaker sol. of C. of Ammonia; or by putting minute splinters of glass on glands.2
If your case of Teazle holds good it is a wonderful discovery. Try whether pure water or weak infusion of raw meat will bring out the protoplasmic masses.3 The closest analogy seems to me that of an independent Amœba or Foraminiferous animal &c which feeds by involving at any point of its gelatinous body particles of organic matter & then rejecting them— A mass of rotting insects would give such particles.— Perhaps this is your view. But I do not understand what you mean by a resinous secretion becoming slimy, or about living insects being caught. I would work at this subject, if I were you, to the point of death.4
If an Amœba-like mass comes out of cells & catches dead particles & digest them, it wd. beat all to fits true digesting plants.
I never saw anything come out of quadrifids of Utricularia & I cd. hardly have failed to see them, as I was on look out for secretion.5 It wd be a grand discovery. Could you chop up or pound excessively fine raw meat, or better decayed meat & colour the particles first, & then you cd see them in the protoplasmic masses; for surely you could hardly expect (unless there is a distinct hole) that they shd. be withdrawn within cells of glands.— The case is grand—
Are any orifices or orifice visible in cut-off summit of gland? For heaven sake report progress of your work.—
I see in last G. Chronicle another man denies that Dionæa profits by absorption & digestion, which he does not deny.6 It seems to me a monstrous conclusion— But this subject ought to be investigated Especially effects on Seed-bearing— Teazles good. for this—
Yours affecly— | C. Darwin
No doubt marginal glands of Drosera answer to glands on serratures of other leaves. Probably glands wd. be found on apices of spikes of Dionæa in bud-state.7
Footnotes
Bibliography
Insectivorous plants. By Charles Darwin. London: John Murray. 1875.
Summary
Discusses FD’s observations on the protrusion of protoplasmic masses by cells of the teasel. Suggests analogy with amoeba. "I would work at this subject if I were you, to the point of death."
Letter details
- Letter no.
- DCP-LETT-10517
- From
- Charles Robert Darwin
- To
- Francis Darwin
- Sent from
- Hopedene
- Source of text
- DAR 271.3: 14
- Physical description
- ALS 4pp
Please cite as
Darwin Correspondence Project, “Letter no. 10517,” accessed on 1 September 2024, https://www.darwinproject.ac.uk/letter/?docId=letters/DCP-LETT-10517.xml
Also published in The Correspondence of Charles Darwin, vol. 24