222 MEDICINAL USES 



obvious bad effects. Thus the action of alum in excessive 

 doses is simply to produce gastro-enteritis, and this because 

 very little of the drug is absorbed. Alum is decomposed 

 in its passage through the intestines, rendering the faeces 

 odourless and somewhat firmer. Over-doses are decomposed 

 and neutralised by small and repeated doses of sodium 

 carbonate, followed by demulcents. 



MEDICINAL USES. Alum closely resembles copper and zinc 

 sulphates, but is less active. It is occasionally given to the 

 dog as an emetic. Applied in a dry state, it absorbs water 

 from the tissues, and hence acts as a mild caustic. It has 

 little or no effect upon the unbroken skin. It coagulates 

 albumin and gelatin, and hence invests the abraded skin 

 and mucous membranes with a protective film, diminishes 

 their blood supply, and thus relieves congestion, and lessens 

 secretion. In virtue of its astringent properties, it is used 

 as a lotion for aphthous or ulcerated conditions of the mouth; 

 as a gargle and spray for sore-throat ; as a dressing for 

 blistered surfaces, as a stimulant injection for leucorrhcea ; 

 and in many of these cases it may be conjoined with glycerin 

 and borax. Alum is occasionally prescribed with opium 

 in diarrhoea and dysentery, but vegetable astringents are 

 preferable. In America, large doses have been given to 

 horses infested with bots. With the object of precipitating 

 lead salts in the intestine, it has been prescribed as an early 

 antidote in lead-poisoning. Alum was formerly given for 

 polyuria in horses, but iodine and iron sulphate are more 

 effectual remedies. To arrest the flow of synovia from open 

 bursse, or joints, finely powdered alum, mixed with two or 

 three parts of wheat flour, or a powder composed of equal 

 parts of dried alum, iron sulphate, and myrrh, is a valuable 

 application. A saturated, aqueous solution is a useful 

 styptic for haemorrhage. For simple conjunctivitis and 

 keratitis, alum (5 grains) and morphine (2 grains), in an 

 ounce of water, form a useful collyrium, but it is said to 

 dissolve the intercellular cement substance of the cornea, 

 and so increase the size of ulcers and lead to perforation. 

 An ointment, made with one part of alum to three or four 

 of lard, or vaseline, will be found useful as a dressing for 

 ulcerated heels and slow-healing wounds. Glycerin of alum, 



