To Edward Frankland   16 July [1873]1

Down, | Beckenham, Kent.

July 16. ’73

My dear Sir,

I am truly obliged to you. I dare say that I shall be able to send the fluid from the glands in about a fortnight; but I doubt whether I shall possibly be able to get as much as you seem to require. Since writing it has occurred to me that the viscid secretion perhaps contains some substance analogous to Pepsine; but whether or not you could detect this I know not.— Would the Carb. of Soda render the testing of any such organic matter difficult?2

If I do not hear from you again I will assume that I had better use the Carb. of Soda.

Pray accept my cordial thanks | & believe me | Yours sincerely | Ch. Darwin

LS

1
The year is established by the relationship between this letter and the letter from Edward Frankland, 15 July 1873.
2
CD refers to the digestive fluid of Drosera. See letter from Edward Frankland, 15 July 1873.

Please cite as “DCP-LETT-8980A,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-8980A