GEORGE II. ROHE, Baltimore.
ALUM.—The alum generally used is an aluminium and potassium sulphate. This salt is likewise official in the U. S. P. It occurs in the form of translucent, whitish, octahedral crystals having a sweetish and strongly-astringent taste. Alum is soluble in water, insoluble in alcohol, and soluble in heated glycerin.
Physiological Action. — Alum is an active astringent. It coagulates albu min, and when, therefore, it is applied to moist mucous membranes, it causes them to turn white. This is intensified by its power over the blood-vessels of the part, which it firmly contracts, probably by stimulating the local vasomotor nerves. It also contracts the tissues, depleting them of their blood. Upon the blood itself it acts as an effective coagulant, and is, therefore, an excellent styptic. When administered to animals, such as dogs, cats, and rabbits, by subcutaneous injection, a soluble salt of alum causes no symptoms at all for three or four days. Then the animal experimented upon suffers from loss of appetite and obstinate constipation, emaciation, lan guor, and disinclination to move. Next there is vomiting and loss of sensibility, as a deep prick with a needle is scarcely felt. When forced to move, the leg is raised, but trembles and twitches vio lently, and is with difficulty placed on the ground. Sometimes there is general tremor or convulsive twitching and sometimes extreme weakness or partial paralysis of the posterior extremities.
There is complete loss of sensibility to pain, while the animal retains its senses. Then the power of moving the tongue and of swallowing is completely lost; even the saliva cannot be swallowed. The symptoms are precisely those of human acute bulbar paralysis. (Mayer and Siem.) Case in which, through gargling with a concentrated alum solution, a portion of the fluid was accidentally swallowed. This was followed by severe abdominal pains, vomiting of mucus and blood (thirty-nine times), and voiding of blood-stained urine. Recovery only after the lapse of thirteen days. Kra molin (Therap. 1N1onats.. 323, 1902).
Alum is credited with antiseptic power by some observers: a quality probably due to its property of coagulating albuminoid bodies. When ingested in sufficient quantities alum irritates the gastric mu cous membrane and causes vomiting.
Therapeutics.—Alum may be said to be useful as an astringent in all catar rhal conditions of the mucous mem branes—those of the upper air-passages, the vagina, and the urethra particularly —in aqueous solutions of from 5 to 20 grains to the ounce. Strong solutions are rarely indicated, their secondary ef fects being those of undue stimulation, namely: irritation.