Calambine is prepared from calumba root (Menispermum pal-mat am) by the following methods: -

(1) Digest the coarsely powdered root in water acidulated with acetic acid; express, filter, boil to J, again filter, add calcium carbonate in slight excess, and evaporate to dryness in a water-bath; powder the residue, and digest in boiling alcohol; it will deposit crystals of calumbine on cooling.

(2) Evaporate tincture of the root (made with rectified spirit) to dryness; dissolve residue in water, and agitate the solution with equal bulk of ether; after short repose, decant the ethereal portion, distil off most of the ether, and set the liquid aside to crystallize. (Wittstock).

'3) The powdered root is covered With a 2 to 3 per cent, solution of oxalic acid for some hours, and the resulting extract is neutralized with ammonia, which takes up the calumbic acid, and leaves the calumbine pure. (Alessandri.)