A solution of brucine is also coloured red by chlorine gas, ammonia changing the colour into yellow.
Flückiger[456] has proposed as a test mercurous nitrate, in aqueous solution with a little free nitric acid. On adding this reagent to a solution of brucine salt, and gently warming, a fine carmine colour is developed.
[456] Archiv f. Pharm. (3), vi. 404.
In regard to the separation of brucine from organic fluids or tissues, the process already detailed for strychnine suffices. It is of very great importance to ascertain whether both strychnine and brucine are present or not—the presence of both pointing to nux vomica or one of its preparations. The presence of brucine may, of course, be owing to impure strychnine; but if found in the tissues, that solution of the question is improbable, the commercial strychnine of the present day being usually pure, or at the most containing so small a quantity of brucine as would hardly be separated from the tissues.
§ 404. Igasurine is an alkaloid as yet but little studied; it appears that it can be obtained from the boiling-hot watery extract of nux vomica seeds, through precipitating the strychnine and brucine by lime, and evaporation of the filtrate. According to Desnoix,[457] it forms white crystals containing 10 per cent. of water of crystallisation.
[457] Journ. Pharm. (3), xxv. 202.