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Darwin Correspondence Project

From Francis Darwin   [after March 1873]1

Dear Father

I’m afraid the albumen theory wont do because in making extract: Belladonna Hyoscyami & Colchici. the albumen is coagulated by heat and filtered out—& in Stramonii it says the “active matters are extracted by proof spirit” so that the albumen wouldnt be got out— Possibly these may save vegetable albumens like casein not coagulable by heat    I will find out—2

Yrs affec | F Darwin


The date is established by the relationship between this letter and the second letter from Francis Darwin, [after March 1873].
Francis refers to Atropa belladonna (deadly nightshade), Hyoscyamus niger (stinking nightshade), Colchicum autumnale (crocus), and Datura stramonium (jimsonweed). CD was trying to ascertain whether it was the albumin or the alkaloid poisons contained in these plants (for example atropine) that affected the leaves of Drosera. See also letter to J. S. Burdon Sanderson, 25 July 1873 and n. 4. Casein is a milk protein, but in the nineteenth century legumin was referred to as vegetable casein.


Fears [CD’s] albumen theory will not work because albumen is coagulated and filtered out in making extracts of belladonna, hyoscyamine, and colchicine [alkaloid poisons].

Letter details

Letter no.
Francis Darwin
Charles Robert Darwin
Sent from
Source of text
DAR 58.1: 132
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 9198,” accessed on 17 September 2021,

Also published in The Correspondence of Charles Darwin, vol. 21