This section is from the book "Dental Medicine. A Manual Of Dental Materia Medica And Therapeutics", by Ferdinand J. S. Gorgas. Also available from Amazon: Dental Medicine.
Styptics which belong to the class of Astringents are medicinal agents capable of arresting hemorrhage when employed externally. They are divided, according to their action, into chemical and mechanical, the chemical styptics coagulating the blood exuding from the part, and at the same time stimulating the tissues to contraction; whilst the mechanical, as lint, felt, spider's web, plaster of Paris, etc., detain the blood in their meshes, or absorb it until it coagulates, and thus arrest the hemorrhage. Among the Astringents which may be classed as Styptics and local astringents are tannic acid, persulphate of iron solution, powdered subsulphate of iron, alum, nitrate of silver, powdered galls, sulphuric acid, matico, gallic acid, perchloride of iron, catechu, oak-bark rhatany, etc.; and as mechanical styptics, collodion, matico, spider's web.
By contraction of the blood vessels internally: digitalis and ergot; also for checking excessive discharges: acetate of lead, carbonate of lead, subacetate of lead, lime water, the application of cold as ice, and of heat, as hot water, etc.
Vesicants, which belong to the class of Epispastics, are medicinal agents capable of producing a serous exudation beneath the cuticle. Included in this class are cantharides, cantharidal collodion, glacial acetic acid, strong solution of ammonia, mustard, etc., etc. (See Epispastics.)