DEUGS ACTING ON THE SKIN 65 



chafing and superficial inflammation when emollients pro- 

 tect 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 not ouly exert a direct sedative influence 

 on the throat, but, either reflexly or in some measure 

 directly, abt on the bronchial 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 Influencing the Secretion of Sweat. 



The mechanism controlling the sudoriparous glands and 

 secretion of sweat, comprises sweat centres in the spinal 

 cord ; secretory nerves proceeding from them with termina- 

 tions in the glands ; the gland cells, and blood vessels of 

 the skin. Any portion of this mechanism may be affected 

 by drugs to increase or diminish sweat secretion. 



(1) Drugs 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 vascu- 

 larity of the skin. Stimulation of the secretory and vasodi- 

 lator nerves usually go hand in hand, since they accompany 

 each other in their course to the sweat glands. 



DIAPHORETICS 



Pilocarpine 



Alcohol 



Spirit of nitrous ether 



Heart stimulants 



External heat 



(Warm drinks) 



Pilocarpine stimulates the gland 

 cells, or secretory nerve-endings. 

 The others act indirectly by pro- 

 moting the vascularity of the 

 skin, and thus the activity of 

 the sweat glands. 



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