Boys and girls up to fifteen or sixteen years of age are much better off without tea, coffee, or cocoa; for they need no artificial stimulants to their appetites, while at the same time their nervous systems are more liable to injury from the harmful effects of over-stimulation. If the beverages are taken at all, they should be taken very weak, and with plenty of milk and cream as well as sugar. ALCOHOL How Alcohol is Made. The most dangerous addition that man has ever made to the water which he drinks is alcohol. It is made by the action of the yeast plant on wet sugar or starch--a process called _fermentation_. Usually the sugar or starch is in the form of the juice of fruits; or is a pulp, or mash, made from crushed grains like barley, corn, or rye. As the spores of this yeast plant are floating about almost everywhere in the air, all that is usually necessary is to let some fruit juice or grain pulp stand at moderate warmth, exposed to the air, when it will begin to "sour," or ferment. Wine. When the yeast plant is set to work in a tub or vat of grape juice, it attacks the fruit sugar contained in the juice, and splits it up into alcohol and carbon dioxid, so that the juice becomes bubbly and frothy from the gas. When from seven to fifteen per cent of alcohol has been produced, the liquid is called wine. It contains, besides alcohol, some unchanged fruit sugar, fruit acids, and some other products of fermentation (known as _ethers_ and _aldehydes_), which give each kind of wine its special flavor. Beer, Ale, and Cider. If the yeast germ be set to work in a pulp or mash of crushed barley or wheat, the starch of which has been partly turned into sugar by malting, it breaks up the sugar into alcohol and carbon dioxid. When it has brewed enough of the starch to produce somewhere from four to eight per cent of alcohol, then the liquid, which still contains about three or four per cent of a starch-sugar called _maltose_, is called beer, or ale. It is usually flavored with hops to give it a bitter taste and make it keep better. If the same process be carried out in apple juice, we get the well known hard cider with its biting taste. Whiskey, Brandy, and Rum. When left to itself, the process of fermentation in most of these sugary or starchy liquids will come to a standstill after a while, because the alcohol, when it reaches a certain strength in the liquid, is, like all other toxins, or poisons produced by germs, a poison also to the germ that produces it. The yeast-bacteria probably produce alcohol as a poison to kill off other germs which compete with them for their share of the sugar or starch. So even the origin of this curious drug-food shows its harmful character. We should hardly pick out the poison produced by one germ to kill another germ as likely to make a useful and wholesome food. [Illustration: PROPORTION OF ALCOHOL IN LIGHT WINE IN BEER IN WHISKEY The liquid shows what part of a tumblerful of each is alcohol.]