314 INORGANIC AGENTS ~ 



Action External. — When applied in dilution to mucous membranes, 

 raw surfaces or wounds, alcohol is a stimulant and local anesthetic; 

 while in concentration, it is irritant and even caustic, coagulating 

 mucus and albumin. If alcohol is allowed to evaporate from the un- 

 broken skin, cooling of the surface and contraction of the superficial 

 blood-vessels ensue, with diminished secretion of sweat; but when alco- 

 hol is rubbed into the skin, it is absorbed, takes up water, hardens the ' 

 integument and causes temporary vascular dilatation. Alcoholic aqueous 

 dilutions containing 60 to 70 per cent, of absolute alcohol are among 

 the most valuable skin disinfectants, equal in germicidal action to 3 per 

 cent, carbolic acid solution. Absolute alcohol, or the undiluted commer- 

 cial alcohol, has no germicidal action on dry bacteria, and alcohol in less 

 than 40 per cent, strength is too weak. 



Action Internal. — Alcohol acts locally upon the mucous membrane 

 of the alimentary canal, as described above, and if swallowed in concen- 

 tration it produces congestion and white patches in the mouth by coagu- 

 lating albumin upon the mucous membrane. The secretion of saliva is 

 increased. In small doses the more powerful alcoholic liquors, as whisky 

 and brandy, aid digestion by stimulating locally the taste buds and appe- 

 tite, and reflexly and locally, the gastric circulation, secretion, movement 

 and absorption. 



Alcohol, above 10 per cent, dilution, tends to inhibit the action of 

 the digestive ferments — gastric and pancreatic — and in so far antago- 

 nizes its beneficial influence on gastric digestion just noted. So, while 

 often aiding digestion, alcohol may fail on this account in some cases. 



In large amounts, alcohol causes inflammation of the walls of the 

 stomach and perverts the normal secretion into a mucous discharge. 

 Alcohol is slightly astringent in the digestive tract, and may relieve pain 

 by its local anesthetic action upon the stomach, and spasm, by stimulat- 

 ing the nervous mechanism controlling the stomach and bowels, and so 

 co-ordinating the peristaltic movements. 



Circulation. — The reputation of alcohol as a circulatory stimulant 

 has been much dimmed by the results of many experimenters . who have 

 found it has no stimulating action on the heart whatever. Still more 

 recent work shows that alcohol, after absorption, has a mild stimulating 

 action on the heart muscle, and when nutrition is low — probably by pro- 

 viding the heart muscle with assimilable nutriment. 



The reason for the supposition that alcohol is a heart stimulant was 

 based on its action in increasing the pulse rate in man. In animals di- 

 luted alcohol does not affect either the rate or force of the heart, ex- 

 cept in poisonous doses, when the pulse is slowed and weakened, owing 

 to weakening of the cardiac systole and the dilatation of the heart cavi- 

 ties. In man the increased pulse rate is attributable to reflex irritation 

 in the mouth, possibly to stimulation of the heart muscle or depression 

 of the vagus center, and to muscular and mental activity produced by 

 alcohol. 



The blood pressure is not materially altered by medicinal doses of 

 alcohol after absorption. Alcohol raises blood pressure, however, after 



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