From Francis Darwin   [after March 1873]¹

Dear Father

I thought that perhaps it might make a difference whether the extracts were made from leaves seeds or roots—

Dalton’s physiology calls legumine, which is the nitrogenous element in peas & beans, “vegetable caseine” but says it is different from casein. De Caisne & Le Maout calls it casein as if it were the same animal casein—³ So I thought that Extr Strammonii might contain some casein or legumin—as there is a good large cotyledonous embryo—but I forgot that it wd be precipited by the alchohol used in making Ex Stramonii at least as far as I can make out fr Lauder Brun⁴ all varieties o f albumin are pp^d. by e-alcohol—

Yrs affec | F D

I think I told you Extr Stram was with proof spirit, that is what I got fr Garrod,⁵ but the B Pharmacopeia says Proof Spirit Ether & Water—⁶ I suppose Garrod only mentions the Proof Sp as being the most important