This section is from the book "Materia Medica And Therapeutics Inorganic Substances", by Charles D. F. Phillips. Also available from Amazon: Materia medica and therapeutics.
2. Astringent and Alterative. - By the latter term we mean to express the modifying effect exerted on tissues, and especially on mucous membranes, whereby an unhealthy condition, usually inflammatory in its nature, is subdued, and healthy action is set up in its place. Trousseau taught that this effect is due to the new agent (nitrate of silver) causing a more powerful inflammation than the original one which it displaces, afterward itself subsiding; and this idea he developed at length under the term, "medication irritante substitutive" ("Materia Medica," i., 537), but we cannot prove the occurrence of any substitutive inflammation of this kind. We refer the effects of the remedy partly to its known physical properties of constricting vessels, of coagulating and disinfecting secretion, and of forming an adherent protective membrane; also, in certain conditions, e.g., in ulceration, the vessels immediately acted on being constringed, those in the neighborhood receive a better supply of blood, and the processes of repair are quickened. The remedial power which is special to the drug, which distinguishes it from other astringents, and by which it modifies nutritive processes, we can only express by the term alterative.
In many forms of disorder accompanied by discharge, whether hemorrhagic, mucous, serous, or purulent, the nitrate, either solid or in injection or spray, is very valuable. (Delioux recommends the hyposulphite of soda and silver as equally astringent and less irritant.)