To Daniel Oliver 15 [September 1860]1
Down Bromley Kent
My dear Sir
I am very much obliged for your information. I will look to Annales des Sienc.2 & have ordered the German Book.—3
With respect to the Australian Drosera, the rate or quickness of closing is the point, on which I am very anxious to have a few observations. I shall be surprised, judging from my observations, if the Australian Drosera can distinguish dry organic & inorganic substances. I found that they closed equally (or nearly so) over any substance, but they released vegetable or inorganic substances much more quickly than flies or meat.—4
The most curious results which I have arrived at, is the recognition by the leaves of fluids containing nitrogen & not containing nitrogen. This power of detecting nitrogen in fluids seems to me quite remarkable.—
Lindley does not refer to Buchanan or Wight, but he speaks in Veg. Kingdom p. 433 bottom of the movement of the Indian Drosera lunata; & I see in Steudel’s Nomenclator the names of Buchanan & Wight in relation to this species.—5
I am surprised, if my instructions were followed by Croker that Leschenaultia has not made pods.—6
I am sorry to hear that the plants in the “isosceles beds” have not seeded better. All experiments require a tantalising amount of patience.
With sincere thanks for all your kindness | Believe me, My dear Sir | Yours sincerely | C. Darwin
It might be worth if you like the job while to put a small drop of milk & of saliva on a leaf of the Australian Drosera. Our Drosera likes milk better than any other drink.—7
Thanks for reference to Annales des Sciences Naturelles.
Requests DO observe rate at which Australian Drosera closes.
On detection of nitrogen in organic fluids.
Please cite as
Darwin Correspondence Project, “Letter no. 2917,” accessed on 29 September 2016, http://www.darwinproject.ac.uk/DCP-LETT-2917