To Francis Galton 8 March [1881]1
Down, | Beckenham, Kent. | (Railway Station | Orpington. S.E.R.)
March 8th
My dear Galton
Very many thanks for your note. I have been observing the immersing tracks, on my walks for several months, & they occur (or can be seen) only after heavy rain. As I know that worms which are going to die (generally from the parasitic larva of a Fly) always come out of their burrows, I have looked out during these months, & have usually found in the morning only from 1 to 3 or 4 along the whole length of my walks. On the other hand I remember having on former years seen scores or hundreds of dead worms after heavy rain. I cannot possibly believe that worms are drowned in the course of even 3 or 4 days immersion; & I am inclined to conclude that the death of sickly (probably with parasites) worms is thus hastened, I will add a few words to what I have said about their tracks, after stating that I fd only a very few dead ones.2 Occasionally worms suffer from epidemics (of what nature I know not) & die by the million on the surface of the ground.—
Your ruby paper answers capitally, but I suspect that it is only by dimming the light, & I know not how to illuminate worms by the same intensity of light & yet of a colour which permits the actinic rays to pass.—3 I have tried drawing triangle of damp paper through a small cylindrical hole, as you suggested, & I can discover no source of error. Nevertheless I am becoming more doubtful about the intelligence of worms.. The worse job is that they will do their work in a slovenly manner when kept in pots, & I am beyond measure perplexed to judge how far such observations are trustworthy.
Ever my dear Galton | Yours most truly | Ch. Darwin
Footnotes
Summary
Discusses dead earthworms on surface of ground after rainfall.
Describes experiments involving sensitivity of earthworms to light and how it reflects on their intelligence.
Letter details
- Letter no.
- DCP-LETT-13078
- From
- Charles Robert Darwin
- To
- Francis Galton
- Sent from
- Down
- Source of text
- UCL Library Services, Special Collections (GALTON/1/1/9/5/7/31)
- Physical description
- ALS 4pp
Please cite as
Darwin Correspondence Project, “Letter no. 13078,” accessed on 28 March 2024, https://www.darwinproject.ac.uk/letter/?docId=letters/DCP-LETT-13078.xml