Tannic Acid: Powdered Galls Extracted with Ether (Pelouze, Pharmacopoeia Form)

Tannic acid (gallotannin) is richest in oak galls: the best, Aleppo galls, hold 50–60 %. This is Pelouze's method in the form the British and United States pharmacopoeias adopted, as given in Thorpe's Dictionary (1913): powdered galls are first kept in moist air, then extracted with ether. The liquid splits into two layers; the lower one is a strong solution of tannic acid that dries to a porous mass. No amounts are given. Ether is very flammable: no flame, fume hood. The picture: our diagram.