Cocoa and chocolate are made from the bean-like seeds of a small tree growing in the tropics and, in cake, or solid, form, contain considerable amounts of fat, and usually sugar and vanilla, which have been added to them to improve their flavor. As, however, only a teaspoonful or so of the powdered cocoa, or chocolate, goes to make a cupful, the actual food value of cocoa or chocolate, unless made with milk, is not much greater than that of tea or coffee with cream and sugar. They contain less _caffein_ than either tea or coffee, but are liable to clog rather than to increase the appetite for other foods.
Effects of Tea, Coffee, and Cocoa. Though the flavors of tea, coffee, and cocoa are so different, they all depend for their effect upon a spicy-tasting substance, called caffein from its having been first separated out of coffee. The caffein of tea is sometimes called _thein_, and that of cocoa _theobromin_; but they are all practically the same substance. Part of the taste of these beverages is due to the caffein, but the special flavor of each is given by spicy oils and other substances which it contains. Caffein acts as a mild stimulant both to the nervous system and brain, and to the heart; as is shown by the way in which tea or coffee will wake us up or refresh us when tired, or, if drunk too late at night, keep us from going to sleep. If used in large amounts, especially if taken as a substitute for food, tea and coffee upset the nervous system and disturb the heart, and produce an unwholesome craving for more.
[Illustration: A MILK STATION IN A CITY PARK
Many cities have established such stations, where people can buy, for a cent or two, a drink that is far better than soda water or any other beverage.]
Their chief value lies in the hot water they contain, which has been sterilized by boiling, while its heat assists the process of digestion; and in the fact that their agreeable taste sometimes gives us an appetite and enables us to eat more of less highly flavored foods, like bread, crackers, potatoes, or rice, than we would without them. They are, also, usually taken with cream, or milk, or sugar, which are real foods and bring their fuel value up to about half that of skimmed milk. So far as they stimulate the appetite and increase the amount of food eaten, they are beneficial; but when taken as a substitute for real food, they are most injurious. A cup of coffee, for instance, makes a very poor breakfast to start the day on; for although it gives you a comforting sense of having eaten something warm and satisfying, it contains very little real food, and soon leaves you feeling empty and tired; just as an engine would give out if you put a handful of shavings into its fire-box, and expected it to do four hours' work on them.