To Edward Frankland 29 September 1873
Down, | Beckenham, Kent.
Sep 29. 1873
My dear Sir
I herewith send the washings of 445 leaves (many of them small & poor) in about 8 oz of your distilled water, with 20 grains of yr Carb. of Soda; but much of the solution has been lost in taking out the leaves.1 I have followed all the precautions suggested by you, but then I have found it impossible to prevent some minute insects, completely hidden amongst the tentacles, being included; so that there will, I presume, be traces of Chloride of Sodium. Secondly, I find that the juice of the footstalk & leaf itself is strongly acid, judging by litmus paper; & it was impossible to keep the cut off footstalk entirely out of the solution. So that there will be some acid from this source, independently of that secreted by the glands; but it seems probable that both are the same acid. There seems to be a good deal of acid secreted by the glands, as the bits of fibrin produced little bubbles in the sol. of Soda.2 I shall be intensely curious to know what the acid is.
I have sent all the leaves wrapped up in tin-foil after they had been washed in the Solution; & if it is not a very difficult job, could you get any of your pupils to ascertain what acid is in the leaves themselves. I would gladly pay for this work if you cd persuade any one to undertake it. In this case the leaves I suppose ought to be washed in order to remove any of the secretion, & then crushed.
I have put the solution into 2 bottles, as I had not a stopper-bottle large enough to hold all;— but all is of the same nature.
I am very much obliged for the large bottle of pure water, & had no idea how difficult it was to get it pure: it will be of especial use to me in a distinct little investigation that I am undertaking. I have written to Dr. Odling to thank him.3
Thank you much for your offer of Mucin &c; but Dr Moore is making this substance & every thing for me which I require, except Ptyalin,4 & this he tells me is very difficult to procure, on account of the difficulty of getting enough Saliva, tho’ I shd want only about 1 or 2 grains.
With sincere thanks | Yours very faithfully | Ch. Darwin
There are thousands of the glands in the soln. & you will see how minute they are & I shall be surprised if they have secreted acid enough to neutralise more than 1 gr of the Soda.—
Footnotes
Summary
Is sending washings of 445 leaves in EF’s distilled water with 20 grains of carbonate of soda. Details of the difficulties and complications involved.
Letter details
- Letter no.
- DCP-LETT-9077A
- From
- Charles Robert Darwin
- To
- Edward Frankland
- Sent from
- Down
- Source of text
- The John Rylands Library, The University of Manchester
- Physical description
- LS(A) 4pp
Please cite as
Darwin Correspondence Project, “Letter no. 9077A,” accessed on 29 March 2024, https://www.darwinproject.ac.uk/letter/?docId=letters/DCP-LETT-9077A.xml
Also published in The Correspondence of Charles Darwin, vol. 21