This section is from the book "A Text-Book Of Pharmacology, Therapeutics And Materia Medica", by T. Lauder Brunton. Also available from Amazon: A text-book of pharmacology, therapeutics and materia medica.
A white, usually amorphous, solid alkaloid.
When rubbed on the skin it causes a tingling sensation, followed by prolonged numbness. It is a very active poison.
Preparation. - The aconitate of aconitine is dissolved out of the pounded root by macerating in spirit. If ammonia were now added, the aconitine would be set free, but being soluble in spirit would not be precipitated. The spirit is therefore recovered by distillation, and the residual extract dissolved in water, in which the aconitate of aconitine is soluble, although the alkaloid is very sparingly so. By adding ammonia, aconitine is precipitated mixed with colouring matter and other principles. It is then dissolved in ether, which leaves the colouring matter behind. The ether is recovered by distillation, and the aconitine further purified by dissolving in water acidulated with sulphuric acid and reprecipitating by ammonia.
Characters and Reactions. - A white, usually amorphous, solid; strongly alkaline to reddened litmus, neutralising acids, and precipitated from them by the caustic alkalis, but not by carbonate of ammonium or the bicarbonates of sodium or potassium. It melts with heat, and burns with a smoky flame, leaving no residue when burned with free access of air.
Solubility. - Soluble in 150 parts of cold and 50 of hot water, and much more soluble in alcohol, ether, and chloroform.