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Darwin Correspondence Project

To John Tyndall   20 October [1875]1

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

Oct. 20th

My dear Tyndall

Your tube with the solution dated Oct. 16th. was quite clean at 8o 30 am on the 19th, but at 4o 30 p.m was slightly muddy. At 8o am today (20th) it was more muddy & contained many Bacteria (& apparently vibrios) in lively movement. I believe that this is all that you wanted to hear.—.2

I very greatly enjoyed your visit & the talking has done me no harm.—

Yours very sincerely | Ch. Darwin


The year is established by the reference to a visit that evidently took place on 16 October; Tyndall visited Down on 16 and 17 October 1875 (Emma Darwin’s diary (DAR 242)).
Tyndall probably brought the test tube when he visited Down (see n. 1, above). Tyndall was engaged in a series of experiments on spontaneous generation and had enlisted a number of prominent observers, including CD, Joseph Dalton Hooker, and others, to confirm his results. For more on Tyndall’s work at this time and his dispute with Henry Charlton Bastian about spontaneous generation, see Strick 2000, pp. 162–7.


Strick, James. 2000. Sparks of life: Darwinism and the Victorian debates over spontaneous generation. Cambridge, Mass.: Harvard University Press.


JT’s tube [of boiled infusion] dated 16 Oct was clear on 19th; on the 20th it was muddy and contained many bacteria in living movement.

Letter details

Letter no.
Charles Robert Darwin
John Tyndall
Sent from
Source of text
Sue and Gerald M. Friedman (private collection)
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 10207,” accessed on 11 April 2021,

Also published in The Correspondence of Charles Darwin, vol. 23