From Lawson Tait 2 June [1875]1
7, Great Charles St. | Birmingham.
June 2
My Dear Sir,
Dr. Burdon Sandersons paper on the leaf currents in Dionoea has set me observing the insectivorous plants, and I wait longingly for your book, that I may see more wonders.2 But some of my independant observations are most curious and one which mere accident has revealed is so startling that I hasten to send it to you, even at the risk of it being already known to you.
This afternoon I was hurriedly summoned from my plants and I left a Dionoea uncovered in a hot drawing room exposed to a full glare of sunshine
When I came back in a few hours it seemed doomed, the leaf stalks being much shrunken Its traps were all open, so I tried to see if its nervous system were dead
I found that irritation of a nerve fibre (and we must I think give them that name) of one side of the traps caused incurvation of the fingers & closure of the flap on the opposite side only!
That is reflex action and as we find reflex action often most marked in certain forms of disease & injury which induce paralysis, it seems to me it occurs in this plant.
For instance, in health tickling the inside of the thigh does not induce elevation of the testicle by contraction of the cremaster muscle,3 save in the infant but after fracture of the spine it nearly always does. My poor dionoea, therefore, was paralysed
From what I have seen I am sure we shall find still greater reason to allow a nervous system for these plants.
I am watching a lot of my mice from whom I removed the tails at birth, and I am coming to the conclusion that the essential use of the tail there is as a recording organ, that is they record in their memories the corners they turn & the height of the holes they pass through by touching them with their tails4 Is not this queer.
With best regards to Mrs. Darwin & with tender recollections of my visit to Down,5 I remain, | Yours ever | Lawson Tait
Footnotes
Bibliography
Insectivorous plants. By Charles Darwin. London: John Murray. 1875.
Summary
Paralysis of the nervous system of Dionaea. Uses of tails of mice.
Letter details
- Letter no.
- DCP-LETT-10007
- From
- Robert Lawson (Lawson) Tait
- To
- Charles Robert Darwin
- Sent from
- Birmingham
- Source of text
- DAR 178: 7
- Physical description
- ALS 7pp
Please cite as
Darwin Correspondence Project, “Letter no. 10007,” accessed on 23 April 2024, https://www.darwinproject.ac.uk/letter/?docId=letters/DCP-LETT-10007.xml
Also published in The Correspondence of Charles Darwin, vol. 23