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The Special Uses of Fruits and Vegetables. We come now to the very much larger but much less important class of foods—the Kindling foods, which help the Coal foods to burn, and supply certain stuffs and elements which the body needs and which the coal foods do not contain. These are the vegetables—other than potatoes and dried peas and beans—and fruits.

Fruits and vegetables contain certain mineral elements, which are not present in sufficient proportions in the meats, starches, and fats. Furthermore, the products of their digestion and burning in the body help to neutralize, or render harmless, the waste products from meats, starches, and fats. Thirdly, they have a very beneficial effect upon the blood, the kidneys, and the skin. In fact, the reputation of fruits and fresh vegetables for "purifying the blood" and "clearing the complexion" is really well deserved. The keenness of our liking for fruit at all times, and our special longing for greens and sour things in the spring, after their scarcity in our diet all winter, is a true sign of their wholesomeness.

Not the least of their advantages is that they contain a very large proportion of water; and this, though diminishing their fuel value, supplies the body with a naturally filtered and often distilled supply of this necessary element of life. One of the best ways of avoiding that burning summer thirst, which leads you to flood your unfortunate stomach with melted icebergs, in the form of ice water, ice cold lemonade, or soda water, is to take an abundance of fresh fruits and green vegetables.

Many of the vegetables contain small amounts of starch, but few of them enough to count upon as fuel, except potatoes, which we have already classed with the Coal foods. Most fruits contain a certain amount of sugar—how much can usually be estimated from their taste, and how little can be gathered from the statement that even the sweetest of fruits, like ripe pears or ripe peaches, contain only about eight per cent of sugar. They are all chiefly useful as flavors for the less interesting staple foods, particularly the starches. In fact, our instinctive use of them to help down bread and butter, or rice, or puddings of various sorts, is a natural and proper one. Like the vegetables, they contain various salts which are useful in neutralizing certain acid substances formed in the body. Soldiers in war, or sailors upon long voyages, who are fed upon a diet consisting chiefly of salted or preserved meat, with bread or hard biscuit and sugar, but without either fruits or fresh vegetables, are likely to develop a disease called scurvy. Little more than a century ago, hundreds of deaths occurred every year in the British and French navies from this disease, and the crews of many a long exploring voyage—like Captain Cook's—or of searchers for the North Pole, have been completely disabled or even destroyed entirely by scurvy. It was discovered that by adding to the diet fruit, or fresh vegetables like cabbage or potatoes, scurvy could be entirely prevented, or cured.[10]

Their Low Fuel Value. How little real fuel value fruits and vegetables have, may be easily seen from the following table. In order to get the nourishment contained in a pound loaf of bread, or a pound of roast beef, you would have to eat: 12 large apples or pears (5 lbs.); 4–½ qts. of strawberries; a dozen bananas (3–½ lbs.); 7 lbs. of onions; 2 doz. large cucumbers (18 lbs.); 10 lbs. of cabbage; ½ bushel of lettuce or celery.

Apples, the most Wholesome Fruit. Head and shoulders above all the other fruits stands that delight of our childhood days, apples. Well ripened, or properly cooked, they are readily digested by the average stomach; though some delicate digestions have difficulty with them. They contain a fair amount of acids, and from five to seven per cent of sugar. Their general wholesomeness and permanent usefulness may be gathered from the fact that they are one of the few fruits which you can eat almost daily the year round, or at very frequent intervals, without getting tired of them. Food that you don't get tired of is usually food which is good for you.

Dried apples are much inferior to the fresh fruit, because they become toughened in drying, and because growers sometimes smoke them with fumes of sulphur in the process, in order to bleach or whiten them; and this turns them into a sort of vegetable leather.

Other Fruits—their Advantages and Drawbacks. Next in usefulness probably come pears, though these have the disadvantage of containing a woody fibre, which is rather hard to digest, and they are, of course, poorer "keepers" than apples. Then come peaches, which have one of the most delicious flavors of all fruits, but which tend to set up fermentation and irritation in delicate stomachs, though in the average stomach, when eaten in moderation, they are wholesome and good. Then come the berries—strawberries, raspberries, blackberries—all excellent and wholesome, when fresh in their season, or canned or preserved.

One warning, however, should be given about these most delicious, fragrant berries; and as it happens to apply also to several of our most attractive foods, it is well to mention it here. While perfectly wholesome and good for the majority of people, strawberries, for instance, are to a few—perhaps one in twenty—so irritating and indigestible as to be mildly poisonous. The other foods which may play this kind of trick with the stomachs of certain persons are oranges, bananas, melons, clams, lobsters, oysters, cheese, sage, and parsley, and occasionally, but very rarely, eggs and mutton. This is a matter which each of you can readily find out by experiment. If strawberries, melons, and other fruits agree with you, then eat freely of them, in due moderation. But if, after three or four trials, you find that they do not agree with you, but make your stomach burn, and perhaps give you an attack of nettle-rash or hives, or a headache, then let them alone.

The banana is of some food value because it contains not only sugar, but considerable quantities of starch—about the same amount as potatoes. But, if bananas are not fully ripe, both their starch and sugar are highly indigestible; while, if over-ripe, they have developed in them irritating substances, which are likely to upset the digestion and cause hives or eczema, especially in children. Bananas should therefore be regarded rather as a luxury and an agreeable variety than as a substantial part of the diet.

Food Values of the Different Vegetables. The vegetables depend for their value almost solely upon the alkaline salts and the water in them, and upon their flavor, which gives an agreeable variety to the diet. Parsnips, beets, and carrots are among the most nutritious, as they contain some starch and sugar; but they so quickly pall upon the taste that they can be used only in small amounts.

Turnips and cabbages possess the merit of being cheap and very easily grown. They contain valuable earthy salts, plenty of pure water, and a trace of starch. But these advantages are offset by their large amount of tough, woody vegetable fibre; this is incapable of digestion, and though in moderate amounts it is valuable in helping to regulate the movements of the bowels, in excess it soon becomes irritating. Both of them, particularly cabbages, contain, also, certain flavoring extracts, very rich in sulphur and exceedingly irritating to the stomach, which cause them to disagree with some persons. If these are got rid of by brisk boiling in at least two waters, then cabbage is a fairly wholesome and digestible dish for the average stomach. And because of its cheapness and "keeping" power, it is often the only vegetable that can be secured at a reasonable cost at certain seasons of the year.

Onions, especially the milder and larger ones, are an excellent and wholesome vegetable, containing small amounts of starch, although their pungent flavor, due to an aromatic oil, makes them so irritating to some stomachs as to be quite indigestible.

Sweet corn, whether fresh or dried, is wholesome, and has a fair degree of nutritive value, as it contains fair amounts of both starch and sugar. It should, however, be very thoroughly chewed and eaten moderately, on account of the thick, firm indigestible husk which surrounds the kernel.