GALLIC ACID

n. Ga2l'ik. Lat., acidumgallicum [U. S. Ph., Br. Ph., Fr. Cod.], sal e entiale gallarum. Fr., acide gallique. Ger., Gallu fiurs, Gallapfelsaure. Trihydroxy benzoic (tr'i oxy benzoic) acid, C8(H,OH,OH,H,OH,COOH.) = C7H6O8, a monobasic, aromatic acid, found in nut-galls, mangoes, the fruit of Caesalnina coriaria, and other vegetable substances. Its presence in these vegetables is believed to be due to fermentative changes taking place in the tannic acid of the plants. See G. a. FERMENTATION. This conversion of tannic acid into g. a. takes place in the animal organism whenever the former substance is ingested, and can also be effected artificially by the action of dilute alkalies and acids. G. a. forms colorle , silky, acicular crystals, usually a ociated with a molecule of water of crystallization, and is of an acid, astringent taste, soluble in 100 parts of cold water, and in about 5 of alcohol; soluble in boiling water and in boiling alcohol. It forms salts called gallates. It is astringent, but does not coagulate albumin [B. 4. 5.1 Glycerine (or glycerite) of g. a. See Glycerinum ACIDI GALLICI. Ointment of g. a. See Unguentum ACIDI GALLICI. [s. 135]