Ɛpsilon

From Heinrich Goldschmidt and E. v. Portheim1   23 April 1876

Prague,

April 23th 1876

Sir,

You will excuse, if we dare direct your attention to an error which we remarked at the lecture of your eximious work on insectivorous plants. For in the fifth chapter we have found the effect of decoction of tea and theïn among the experiments with substances free of azot, though the formula of theïn is C8H10N4O2 + H2O.2

You surely will pardon us this little correction arising from the reason to rid your excellent book of the only error. You may believe this as having proceeded from the sentiment of veneration and admiration which we, two zealous adherents of your eminent theory, feel for you.

We are | Yours respectfully | Heinrich Goldschmidt | E. v. Portheim

Prague, 420–I

CD annotations

Top of letter: ‘Answer’ pencil
1
The second correspondent is probably Eduard Porges von Portheim. His nephew Max Porges von Portheim was also a chemistry student at the University of Prague around the same time as Goldschmidt.
2
Theïn (German): theine (caffeine, when it is in tea; OED). Azote is an old name for nitrogen, a component of theine. In a section on non-nitrogenous fluids in Insectivorous plants, pp. 78–9, CD recorded experiments on Drosera leaves with a strong infusion and a weak decoction of tea, as well as what CD described as ‘the chemical principle of tea, namely theine’. He did not give the chemical formula for theine but on page 204 he referred to it as an alkaloid, so he was aware that it contained nitrogen.

Please cite as “DCP-LETT-10467,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-10467