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Letter 10517

Darwin, C. R. to Darwin, Francis

[29 May 1876]


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.”



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.f2

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.f3

The closest analogy seems to me that of an independent Amœba orForaminiferous animal &c which feeds by involving at any point of itsgelatinous body particles of organic matter & then rejecting them— A mass ofrotting insects would give such particles.— Perhaps this is yourview. But I do not understand what you mean by a resinous secretion becomingslimy, or about living insects being caught. I would work at this subject, if I were you, to the point of death.f4

If an Amœba-like mass comes out of cells and catches deadparticles & digest them it wd. beat all to fits true digestingplants.

I never saw anything come out of quadrifids of Utricularia & I cd. hardlyhave failed to see them, as I was on look out for secretion. It wd be a granddiscovery. Could you chop up or pound scraping from raw meat, orbetter 12 decayed meat & colour the particles first, & then youcd see them in the protoplasmic masses; for surely you could hardlyexpect (unless there is a distinct hole) that they shd. bewithdrawn within cells of glands.— The case is grand—

Are any orifices or orifice visible in cut-off summit of gland? For heavensake report progress of your work.—

I see in last G. Chronicle another man denies that Dionœa profits by absorption & digestion, which he does not deny.f5 It seems to me a monstrousconclusion— But this subject ought to be investigated  Especially effects on seed-bearing— Teazles good. for this—

Yours affectionly— | C. Darwin

No doubt marginal glands of Drosera answer to glands on serratures of otherleaves. Probably glands wd. be found on apices of spikes of Dionæa in bud-state.f6

DAR 271.3: 14



The date is established by the relationship between this letter and the letters from Francis Darwin, [28 May 1876] and [29 May 1876]. CD evidently wrote ‘Monday’ in error; 30 May 1876 was a Tuesday.
CD’s advice was in response to Francis Darwin’s complaint about aggregated protoplasm forming motionless masses (see letter from Francis Darwin, [29 May 1876]). CD refers to a solution of carbonate of ammonia.
See letter from Francis Darwin, [28 May 1876] and n. 3.
See letter from Francis Darwin, [28 May 1876] and n. 4.
There was a brief note on Dionaea muscipula (Venus fly-trap) in Gardeners’ Chronicle, 27 May 1876, p. 689.
See letter from Francis Darwin, [28 May 1876] and n. 5.
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