33 8 MATER i A MEDIC A AND THERAPEUTICS. 



" passive " discharge of plasma and leucocytes is escaping 

 from their walls, as in chronic inflammation, the exudation is 

 stopped. Thus tannic acid is a powerful indirect styptic and 

 astringent. Broken surfaces, such as ulcers, have their super- 

 ficial layers of cells condensed, and the discharge disinfected 

 and coagulated, thus promoting healing. It is a remarkable 

 fact that tannic acid does not actively contract blood-vessels, 

 like lead and silver ; on the contrary, it dilates them ; but the 

 indirect or constringent influence more than neutralises this. 



There is hardly a limit to the application of tannic acid, 

 and preparations containing it, as astringents and styptics. 

 Superficial haemorrhage from small wounds, the nose, gums, 

 throat, etc., and chronic or subacute inflammatory discharges 

 from the skin, eyes, nose, urethra, vagina, womb, or rectum, 

 may all be treated with it. The acid may be used solid, being 

 dusted or insufflated on the part; in solution as injection, 

 lotion, etc. ; or inserted into canals or cavities as bougies or sup- 

 positories. The two ointments of galls are favourite applica- 

 tions to haemorrhoids. 



Internally. In the mouth, tannic acid produces its peculiar 

 " taste," with a sensation of astringency, dryness, roughness, 

 stiffness of the tongue and throat, and thirst ; the parts being 

 constringed and partially anaesthetised, and the other effects 

 produced, as described, externally. Preparations containing 

 this drug are in much request in chronic sore throat with a 

 relaxed condition of the uvula, pharynx, and larynx, slight 

 catarrh, cough, and occasional slight bleeding. The trochisci, 

 gargles, sprays, or the glycerine applied with a brush, may be 

 used in different cases. 



In the stomach, tannin precipitates the pepsin with the 

 albumens of the gastric juice ; and if in quantity, will inter- 

 fere with digestion by this means, as well as by constringing 

 the mucosa, reducing the circulation, and diminishing the 

 secretion. On the contrary, if a chronic gastric catarrh be 

 present, causing dyspepsia, tannin will give relief by arresting 

 the morbid process, on the principles already discussed. 

 Haemorrhage from ulcer of the stomach is often successfully 

 treated by free (1 dr.) doses of the acid, which acts as a direct 

 styptic. In the stomach another highly important use is made 

 of the drug, viz. as an antidote to antimony, and such alkaloids 

 as morphia, nicotin, strychnia, etc. ; a strong infusion of tea 

 being given if no other tannate is at hand. An emetic or 

 purgative should be afterwards given in alkaloidal poisoning, 

 as the compounds with tannic acid are not perfectly in- 

 soluble. 



The astringent effect of tannin is continued in the in- 



