Ethyl alcohol is the active principle of alcoholic beverages. It is produced by fermenting sugars with yeast. The difference in these beverages is due in part to the kind of sugar used, in part to the kind of ferment, and largely to by-products of fermentation that help to give flavor to them.

Alcoholic beverages do so much harm that their utility under any circumstances has been denied. It is true that they are unnecessary as beverges and even as medicines, for there are other things that can produce all the good results ascribed to them, but they do excite definite physiologic effects that are often forgotten because of their common use as drinks.

A man in health does not need to use alcohol; but it is so extensively employed the world over either to produce factitious exhilaration, or, by lessening sensibility, to mitigate fatigue and discomfort, sorrow and suffering, and it has been so largely and often so injudiciously used in disease, that it demands consideration. As the physiologic effects of beverages containing alcohol are due practically to this factor alone, it seems well to discuss these effects before describing the various forms of alcoholic beverages.

Alcohol is a poison to protoplasm which checks the activities of living matter and may kill it. By a rapid abstraction of water it precipitates albumin. The latter may be quickly redissolved in water if it has not been left too long in the alcohol. After a certain time resolution is impossible. When alcohol is taken into the mouth, it causes a sense of warmth in the mucous membranes, causes them to be unusually congested, and forms upon the surface a pellicle of precipitated albumin that is rapidly washed off by the saliva. The latter is formed in unusually large amounts because of the irritation of the mouth by the alcohol. In contact with the mucous membranes of the stomach it causes similar changes. It also increases the formation of gastric juice, provokes more vigorous peristalsis of the stomach, induces congestion of its mucous membrane, and thus excites an excessive secretion of mucus. If a large amount of concentrated alcohol is swallowed, it will produce acute inflammation of the stomach. If moderate amounts are taken frequently, and especially upon an empty stomach, it will gradually cause subacute inflammation.

The chemical changes of digestion are not affected by very dilute solutions of alcohol. Five to 10 per cent., however, retards them, and 20 per cent, stops digestion. Strong alcoholic solutions precipitate the pepsin of the gastric juice and coagulate the albumin of foods, making them less soluble. Pancreatic digestion is more easily affected by alcohol than is peptic digestion. From 2 to 3 per cent, will retard it. Two tablespoonfuls of brandy delay the digestion of a meal in the stomach for a half-hour.