ACIDUM GALLIC UM. 337 



salts of antimony, lead, silver; persalts of iron, 

 alkaloids, vegetable emulsions. 

 Dose. 2 to 10 gr. 



Preparations. 



a. Glvcerinum Acidi Tannici. 1 to 4. Dose, 10 to 40 



min. 



b. Suppositoria Acidi Tannici. 3 gr. in each. 



e. Suppositoria Acidi Tannici cum Sapone. 3 gr. in each. 

 d. TrochiBci Acidi Tannici. J gr. in each. Dose, 1 to 6. 



2. Acidum Galli cum. Gallic Acid. H 3 C 7 H 3 

 O 5 .H 2 O. A crystalline acid prepared from galls. 



Source. Made by fermenting a paste of powdered galls 

 and water, boiling with water, straining, and purify- 

 ing the crystalline product. 



Characters. White or pale fawn silky needles, with an 

 acid taste. Solubility: 1 in 100 of cold water, 

 1 in 3 of boiling water, 1 in 8 of spirit, 1 in 20 

 of glycerine. It may be combined with the proto- 

 salts of iron. Resembles Tannic Acid, but has no 

 astringent taste, and does not precipitate solutions 

 of gelatine. 



Incompatible*. Spiritus JEtheris Nitrosi ; metallic salts, 

 including per-salts of iron. 



Dose. 3 to 10 gr. 



Preparation. 



Glycerinum Acidi Gallici. 1 to 4. Dose, 10 to 60 min. 



ACTION AND USES. 

 1. IMMEDIATE LOCAL ACTION AND USES. 



Externally. The action of tannic acid, and of the many 

 officinal substances which contain it, including oak-bark and 

 galls, depends upon its property of precipitating albumen and 

 gelatine. "When applied to the skin or exposed mucous surfaces, 

 it condenses or constringes the albuminous and connective 

 tissues, and coagulates the fluids pervading the solid elements 

 (an action which in the dead skin converts the whole into leather). 

 At the same time the sensibility of the nerves is reduced. The 

 vessels are com pressed by the constringed tissues to such a degree 

 that their size is indirectly reduced, the circulation through 

 them diminished, and haemorrhage from them arrested by 

 pressure and by coagulation of the blood by the acid. If a 

 W 8 



