To J. S. Henslow 28 [September 1860]
15 Marine Parade | Eastbourne.
My dear Henslow
Just before coming here for our poor girl’s health (I am glad to say that she has benefitted decidedly from sea-air) I received your little note, telling me that you were not quite satisfied on antiquity of the Celts.1
I fear that this truly dreadful weather will give me no chance of my weed-seeds.—2
My object in writing now is to beg for a bit of information; & I cannot think of any one else to apply to, otherwise I would not have troubled you.—
I have been making a great number of observations on the leaves of Drosera, & have come to some curious results about their power of discriminating nitrogenised compounds.—
When the viscid hairs contract or become inflected; they pour out much fluid & the contents of the cells in the footstalks, instead of being a thin pink homogeneous fluid, becomes a broken mass of dark red, thick fluid. When the cells are in this condition, the particles circulate round the cell, as if driven by ciliæ. I believe that this is not an uncommon circumstance: is it? But what has surprised me is that the globules & cylinders of the thick dark red fluid or substance keeps on an incessant slow contracting & expanding movement: they often coalesce & then separate again; they often send out buds, which rapidly increase at the expence of the larger parent mass; in short endless slow changes in form.3 These slow incessant movements, which are quite independent of the circulation, resemble the movements of sarcode in the protozoa.4
Is any such phenomenon known? it may be quite common, as I am so ignorant of vegetable physiology.— It has surprised me much. Will you be so very kind, whenever you have a little leisure, to let me hear—
I hope you have returned well & strong after your tour.
What a wonderful start this of Hooker’s.!—5
My dear Henslow | Yours affectionately | C. Darwin
P.S. Though I cannot conceive how it can be effected, I presume that the movement in the red matter must be due to slow absorption of water. Yet how this should make the globules coalesce, divide, coalesce again & bud out into new globules, it is hard to understand.—
Has been observing Drosera. Asks JSH whether a curious motion in the red fluid poured out from the viscid hairs is a known or common phenomenon. It surprised him, but he is "so ignorant of vegetable physiology".
Please cite as
Darwin Correspondence Project, “Letter no. 2932,” accessed on 17 January 2017, http://www.darwinproject.ac.uk/DCP-LETT-2932