TANNIC ACID 591 



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 

 «ther, chloroform, benzol or benzin. 



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

 ferric, lead and antimony salts, gelatin and emulsions. 



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

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



PREPABATIONS. 



Collodium Styptieum. Styptic Collodion. (TT. S. P.) 



Tannic acid, 30; alcohol, 5; ether, 35; collodion, to 100. Made by 

 solution. 



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

 Tannic acid, 30; benzoinated lard, 80. 



Olyoeritum Acidi Tannici. Glycerite of Tannic Acid. 

 (U. S. &B. P.) 

 Tannic acid, 30; 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 mouths 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 — through the forma,tion of protein tannate. It is 

 the most important astringent principle contained in 

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

 or haemostatic in arresting hemorrhage by contraction of 

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

 blood, and constriction of the tissues surrounding the blood 



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