Preparation. - By concentrating the mother-liquors after the crystallisation of sulphate of quinine, purifying by crystallisation from alcohol and finally from hot water.

Characters. - In colourless silky crystals, usually acicular.

Solubility. - Soluble in water, alcohol, or ether; almost insoluble in chloroform or in solution of ammonia; readily soluble in diluted acids.

Reactions. - The solution in water has a bitter taste and a neutral or faintly alkaline reaction, twists a ray of polarised light to the left; when acidified is not distinctly fluorescent. For other tests, vide p. 941.