54 GENERAL ACTION OF DRUGS 



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 decomposition and infection. 



(B) Drugs Locally Softening, Soothing and Protecting the Skin, 



Emollients. 



They include: Olive oil 



Lard Cottonseed oil 



P etr olatum L anolin 



Cacao butter (Fomentations — Poultices) 



Demulcents are drugs exerting a soothing, protecting and softening 

 influence on the mucous membrane of the alimentary canal, when given 

 internally. They are mostly gums, syrups and albuminous fluids, as : 



Acacia Glycerin 



Linseed infusion or tea White of egg 



Liquorice Milk 



Syrup Starch 



Molasses Sweet oil 

 Honey 



Uses. — Emollients are serviceable in softening the skin when it has 

 a tendency to be dry and fissured; also in chafing and superficial inflam- 

 mation when emollients protect the skin from the natural irritation of the 

 air. 



Demulcents are of value in inflammation of the mucous membrane 

 of the digestive tract (olive oil, not starch or gums, which may decompose 

 and irritate), and again in catarrh of the mucous membrane of the upper 

 respiratory tract, because they exert a direct sedative influence on the 

 throat, and either reflexly or in some measure directly, act on the bron- 

 chial tubes. Demulcents are often employed to relieve irritation in the 

 urinary tract, but after their decomposition in the alimentary canal and 

 absorption into the blood they can not act as such. They act chiefly by 

 supplying water. 



(C) Drugs Influj:ncing the Secretions of Sweat. 



The mechanism controlling the sudoriferous glands and secretion of 

 sweat, comprises sweat centres in the medulla and spinal cord; secretory 

 nerves proceeding from them with terminations in the glands ; the gland 

 cells, and blood vessels of the skin. Any portion of this mechanism may 

 be ailected by drugs to increase or diminish sweat secretion. 



(1) Drwgs increasing the secretion of sweat, or diaphoretics. 

 They may: 



(1) Stimulate the sweat centres. 



(2) Excite the secretory nerve-endings in the glands. 



(3) Increase the activity of the gland cells. 



(■4) Stimulate the vasodilators and increase the vascularity of the 

 skin. Stimulation of the secretory and of the vasodilator nerves usually 

 go hand in hand, since they accompany each other in their course to the 

 sweat glands. 



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