STYPTICS 61 



small quantity, or diluted solution, are astringent. Agents, 

 such as ergot, digitalis, and adrenalin, have no coagulant 

 power on albumin, but eonstringe the tissues, in virtue of 

 their action on the walls of the nutrient arterioles. Experi- 

 ments made by Stockman with gallic acid show that it has 

 no claim to any special coagulant action nor any effect in 

 lessening, like ergot, the calibre of blood-vessels, either by 

 peripheral or central action. The remote effects of vegetable 

 and other astringents have been overestimated. So soon 

 as their chemical affinities have been satisfied by union with 

 a base or with albumin, they must evidently lose their 

 power of coagulating or precipitating albumin ; and it is 

 therefore difficult to comprehend how they can exert 

 astringent effects upon either the respiratory or the urinary 

 mucous membrane. 



Astringents are used to diminish excessive, and modify 

 faulty, secretion, to combat congestion of cutaneous and 

 mucous surfaces, and to arrest limited recent superficial 

 inflammation. These results appear to be obtained in 

 several ways. Usually some change is effected in the vas- 

 cular walls, or in the perivascular connective tissues, not 

 always, however, by narrowing the vessels, for such notable 

 astringents as alum and tannic acid dilate vessels ; while 

 silver nitrate acts on the cement substance of the endo- 

 thelium. Their efficacy is often well seen in circumscribed 

 inflammation of the conjunctiva or fauces. Solutions of 

 tannin, eucalyptus gum, or alum, in spray or gargle, or 

 inhalations of turpentine vapour, mixed with air, arrest the 

 inordinate secretion, and relieve the congestion of sore 

 throat and bronchitis. Their application in disorders of the 

 digestive organs will receive special notice under that head- 

 ing. As injections and suppositories, they are used in 

 irritable and inflamed conditions of the vagina and uterus. 

 The uterus and rectum, when prolapsed, are washed with 

 astringent antiseptics, in order to diminish their irritability 

 and swelling, and to facilitate their safe return. They con- 

 dense exuberant granulations, lessen discharges from wounds 

 and ulcers, which they usually coat with a protective film 

 of albumin. 



STYPTICS are astringents specially used to arrest bleeding. 



