A solution of potassium hydroxide (caustic potash) containing about five per cent of the hydroxide.
Derivation.—Boiling a solution of potassium carbonate with calcium hydrate leaves potassium hydrate in solution, while calcium carbonate is precipitated.
Properties.—A clean, clear colored liquid, odorless, having a very acrid and caustic taste.
Dose.—Horses and cattle, 1⁄2 to 1 oz.; sheep and pigs, 1⁄2 to 1 dr.; dogs, 5 to 10 m.
Action and Uses.—Externally potassium hydroxide and the solution of potassium hydroxide are irritant and caustic, when applied they abstract water from the parts. They dissolve fatty matters, antacids and if well diluted acts as a sedative. Internally not used to any extent, as milder salts of potassium are preferred, is antacid, alterative, febrifuge and diuretic. Large undiluted doses corrode and inflame the alimentary tract, cause colicy pains, great depression and sometimes perforations. Caustic potash is sometimes used to destroy warts and fungous growths. A dilute solution is used to cauterize poisoned wounds, but is dangerous, as it may penetrate too deeply and spread. This can be overcome by washing with vinegar.
POTASSII IODIDUM—POTASSIUM IODIDE
Derivation.—Potassium iodide may be prepared in the same manner as potassium bromide iodine, being used in place of bromine.
Properties.—It is a colorless, transparent, translucent, or opaque white, cubical crystals, or white granular powder, having a peculiar, faint, iodine-like odor and a pungent, saline, afterwards bitter, taste. Permanent in dry air and but slightly deliquescent in moist air. Soluble in 0.7 parts of water, and in about 12 parts of alcohol at 77° F., in 0.5 parts of boiling water, in 6 parts of boiling alcohol; also soluble in 2.5 parts of glycerine.
Actions.—Potassium iodide closely resembles iodine but is less powerful and devoid of local irritant action. Medical doses are antiseptic, desquamatic, deobstruent, expectorant, alterative and diuretic. It stimulates the lymphatic system. It is readily soluble, and is quickly absorbed in the tissues, where it undergoes decomposition; the iodine, when liberated, apparently combines with albuminoids and acts specially on the lymphatic glands and vessels, modifying nutrition, hastening metabolism and promoting absorption. It is doubtless in this way that it also unites with lead and mercury deposited in the tissues, renders them soluble, carries them into the circulation and causes their elimination.
It is quickly excreted by the mucus and skin surfaces, but chiefly by the kidneys.