58 MATER i A MEDIC A AND THERAPEUTICS. 



is somewhat caustic if the skin be broken, for instance, over 

 ulcers. It is used to destroy weak exuberant granulations. 



Internally. The local action of alum is appreciated in the 

 mouth as an " astringent taste,'' and in the throat as," dryness," 

 the mucous secretions of the parts being coagulated, and the 

 membrane constringed, especially if the parts be inflamed and 

 swollen. Alum is therefore a remedy for sore throat, in the 

 form of gargles or sprays, variously combined with other sub- 

 stances. 



A similar effect is produced on the mucous membrane of 

 the stomach and intestines, dyspepsia and constipation being 

 the result ; in large doses it is an emetic, irritant, and purga- 

 tive. A teaspoonful mixed with syrup is an excellent vomit in 

 croup. As an injection in discharges from the vagina, uterus, 

 and urethra, it is in constant use ; and also as a wash for the 

 eyes. 



2. ACTION IN THE BLOOD. 



Alum is absorbed into the blood, probably as an albumi- 

 nate. 



3. SPECIFIC ACTION AND USES. 



This salt is believed to possess astringent properties when 

 it reaches the tissues, arresting haemorrhage and chronic in- 

 flammatory discharges from the mucous membranes ; and is 

 used in the treatment of haemoptysis, epistaxis, gleet, diarrhoea, 

 and even whooping cough. Much of this is doubtful. 



4. REMOTE LOCAL ACTION AND TSES. 



Alum is excreted by the kidneys, and may arrest haemor- 

 rhage from these organs. Part of the salt may also escape 

 by the skin, as it proves useful in some cases of excessive 

 sweating. 



PLUMBUM. Pb. 207. LEAD. 

 Lead is one of the most powerful and useful of 

 metallic drugs. 



1. Pliimbi Oxidmii. Oxide of Lead. Litharge. PbO. 

 Characters. Heavy scales of a pale brick-red colour. So- 

 luble in diluted nitric and acetic acids. 



Impurities. Copper, iron, and carbonates ; detected by 

 ordinary tests. 



Preparations. 



Emplastrum Plumbi. Lead Plaster. 1 in 2| of 

 Olive Oil and 1 of Water. 



