TANNIC ACID 565 



part of alcohol ; also in 1 part of glycerin, with the interven- 

 tion of moderate heat ; freely soluble in diluted alcohol ; 

 sparingly in absolute alcohol ; almost insoluble in absolute 

 ether, chloroform, benzol or benzin. 



Incompatihles. — Alkaloids, alkalies, mineral acids, silver, 

 ferric, lead and antimony salts, gelatin and emulsions. 



Dose.—U. & C, 3ss.-5ss. (2.-15.); Sh. & Sw., 3 ss.-i. 

 (2.-4); D., gr.i-xv. (.06-1.). 



PREPARATIONS. 



Collodium Stypticum. Styptic Collodion. (U. S. P.) 

 Tannic acid, 20; alcohol, 5; ether, 25; collodion, to 100. Made by 

 solution. 



Unguentum Acidi Tannici. Ointment of Tannic Acid. (U. S. P.) 

 Tannic acid, 20; benzoinated lard, 80. 



Olyceritum Acidi Tannici. Glycerite of Tannic Acid. 

 (U. S. &B. P.) 

 Tannic acid, 20; glycerin, 80. (U. S. P.) 



Administration. — Tannic acid is given in solution in 

 aromatic waters, alcohol, syrup, wine, glycerin, and water; 

 also it is exhibited in powder. The drug is used externally 

 in powder, ointment, glycerite, and lotion. Suppositories 

 containing tannic acid are sometimes introduced into the 

 rectum. 



Action External. — Tannic acid coagulates albumin, gela- 

 tin, and fibrin. It has little effect upon the unbroken skin, 

 but when applied to a raw surface or mucous membrane, it 

 coagulates and dries secretion, and so fills up the njouths of 

 glands, making the tissues harder, denser, and drier. Tannic 

 acid causes a species of "tanning" compatible with life, by 

 occasioning coagulation of the interstitial fluid in the tissues, 

 abstraction of moisture, and contraction of the cells of the 

 part. It is the most important astringent principle contained 

 in vegetable drugs. Tannic acid is, moreover, a local styptic 

 or haemostatic in arresting haemorrhage by contraction of 

 the smooth muscles of the vessel walls, by coagulation of the 

 blood, and constriction of the tissues surrounding the blood 



