ACIDUM GALLICUM — GALLIC ACID 265 



are insoluble in water and dilute acids but soluble in alkalies. They 

 are all obtained by the precipitation of proteids with tannin. 



Tannalbiu is a light brown, tasteless, odorless powder contain- 

 ing about 50 per cent, of tannin. It is nothing more than a dried 

 tannin albumen precipitate. Taunocol is a similar gelatin precipi- 

 tate, while tannigen is the acetic ester of tannic acid (acetyl tan- 

 nin). Tannopin is formed by a combination of hexamethylen- 

 amine (urotropin) and tannin. Tannoform is a similar com- 

 pound of tannin with formaldehyde. These are all yeUow powders, 

 odorless, tasteless and incompatible with alkalies. They are all used 

 for their local action upon the intestines, are less liable to produce 

 irritation than tannin and may be used interchangeably. Tanno- 

 form and tannopin may also be used as astringent dusting powders 

 upon open wounds either alone or in combination with starch 1 — 5. 

 They are indicated particularly in acute intestinal catarrh after the 

 cause of the disease has been entirely removed. Their doses are 

 about twice that of tannic acid. 



ACIDUM GALLICUM — GALLIC ACID 



This is the hydrid of tannic acid. It occurs in many plants 

 usually along with tannin. It is prepared by boiling tannic acid 

 with weak acids, occurs as pale fawn colored, silky needles, odorless, 

 of an astringent taste, and permanent in air. It is soluble in 83.7 

 parts of water, 4.14 parts of alcohol, and 12 of glycerin. It differs 

 from tannic acid in not precipitating gelatin or albumen. 



Action and Uses. Externally it is an astringent but much 

 weaker than tannic acid. It does not coagulate blood so cannot serve 

 as a styptic. Gallic acid has been recommended as a hemostatic in 

 hemorrhages that can be reached by the circulation but its reputa- 

 tion for this action is entirely without foundation as it is absorbed 

 and eliminated unchanged and does not possess such an action even 

 when applied locally. It is occasionally of service in reducing the 

 amount of urine in diabetes insipidus or polyurea. 



It is incompatible with ferric salts, tartar emetic, lead acetate, 

 silver nitrate and spirits of nitrous ether. 



Doses same as tannic acid. 



GALLA — GALLS 



Synonyms. Nut Galls, Smyrna Galls 



Nutgalls is the excresences on the leaves of an oak, Quercus in- 

 fedona, caused by the punctures and deposited ova of a wasp 

 (Oynips tindoria). This particular oak grows in countries bor- 

 dering on the Mediterranean. The activity is due to tannic acid 

 of which it contains from 30 to 60 per cent. 



