To J. S. Henslow 11 October 
15 Marine Parade | Eastbourne
My dear Henslow
Very many thanks for your pleasant letter just received from Down, with many things which interested me.1 I am particularly obliged for answer about contracting & expanding red thick fluid substance. I have been observing it with great care. & it really is a most curious phenomenon.— It all takes place within the same cell. & is, I now find certainly not from endosmose or exosmose from any external fluid;2 for a hair cut off & put dry between two slips of glass, shows the phenomenon splendidly. I have outline of a whole series of changes; which are infinitely varied & never cease. The movement can never be seen until after the hairs have contracted over a Fly or other substance.3 But I shall write a paper on the subject: so will not trouble you any more.—
You have told me what I wanted to know, whether it was some well phenomenon.—4
Yours affect | C. Darwin
Dr. Bree “pitches” into me handsomely.—5
Sends further details on the movement of the red fluid substance in Drosera. Will write a paper on it.
"Dr [C. R.] Bree ""pitches"" into me handsomely."
Please cite as
Darwin Correspondence Project, “Letter no. 2945,” accessed on 6 May 2016, http://www.darwinproject.ac.uk/DCP-LETT-2945