64 GENERAL ACTIONS OF DRUGS 



rhage, when locally applied, both by coagulation of albumin 

 of the blood and by direct contraction of the vessels and 

 tissues surrounding them. The solutions of ferric alum, 

 ferric chloride and subsulphate are the most powerful styp- 

 tics, although all astringents possess an haemostatic action. 



Uses. — Astringents are employed in local loss of tone 

 and relaxation of tissues accompanied by serous, mucous or 

 purulent exudation from mucous membranes or raw surfaces. 

 The irritating astringents are usually contra-indicated in 

 acute inflammatory conditions, but are thought to prevent 

 the out-wandering of leucocytes through the blood vessels, 

 which results in purulent exudation. 



Styptics are employed in the treatment of haemorrhage 

 from mucous membranes, or in bleeding from other parts 

 which cannot be stopped by surgical means, heat or cold. 

 The coagulated blood is prone to sepsis, speedy decomposi- 

 tion and infection. 



(B) Drugs Locally Softening, Soothing and Protecting 

 THE Skin, or Emollients. 



Demulcents are drugs exerting a soothing, protecting and 

 softening influence on the mucous membrane of the aliment- 

 ary canal, when given internally. They are mostly gums, 

 syrups and albuminous fluids, as : 



Uses. — Emollients are serviceable in softening the skin 

 when it has a tendency to be dry and fissured ; also in 



