In the lesson on "Vieno System of Food Measurement" I give the energy value of various fruits, and also the nitrogen factor. These tables consider fruits in the same light with other foods; that is, as sources of energy and nitrogen. In the table which follows, the more important fruits are grouped according to their total acidity. The figures represent the volume of acidity, not strength:

Acid Fruits

Subacid Fruits

Sweet And Non-Acid Fruits

The fruits in the above table are all reasonably wholesome, and the particular fruits to be used depend as much upon convenience as upon the nature of the food substances. The above groups, however, will be given much attention in dietetic prescriptions, and the food scientist should become thoroughly familiar with this classification.

Of the acid fruits, oranges are the best and most desirable, and cranberries perhaps the least.

Acid fruits are responsible for much stomach and intestinal trouble. Food was prior to life. Animal life on this globe has been fitted into, and is the net result of food; therefore, in the wonderful adaptations of Nature, it is evident that life will develop higher and better by subsisting upon the food that grows in its respective country.

Evils of acid fruit in northern countries.

Acid fruits, such as lemons, limes, grapefruit, pineapples, and oranges, are grown in the tropical and semi-tropical countries, where the climate is warm, and where people subsist largely upon native vegetables. These fruits supply the acids and the fruit-sugars which the system requires in a warm climate.

In the tropics the people live out of doors, the pores of the skin are kept open, and the effete matter produced by acids can be cast out of the body.

In northern countries people live largely indoors, and are heavily clad except during a very short term in midsummer, therefore they do not eliminate freely. They subsist largely upon the heavier foods, such as flesh and grains, both of which require a large amount of hydrochloric acid for digestion, hence when the acid of citrus-fruits is added to the hydrochloric acid, of which most people have too much, serious acid fermentation is the result.

Value Of Subacid Fruits

Acid fermentation is the beginning of nearly all stomach trouble, and is the primary cause of many other ills. (See "Fermentation," p. 424.)

Practically all the fruits of the subacid group are excellent; however, on account of the mechanical irritation of the seeds, berries should not be used in cases in which the stomach and the intestines are irritated or catarrhal. In such cases the juice should be pressed from the fruit and the seeds discarded.

Of the non-acid fruits, raisins, figs, and dates are excellent foods from the standpoint of furnishing a large amount of sugar in its very best form. Very ripe bananas and ripe persimmons, especially the large Japanese variety, are fruits which have a distinct nature, and are suited to a particular purpose in dietetics. These pulpy fruits are especially desirable in all cases of digestive irritations and disorders, because of the amount of nourishment contained in them, which is greater than that contained in the juicy fruits. In my practice I seldom, if ever, find a stomach so weak that it cannot digest ripe persimmons and very ripe bananas. I attribute much of my success in treating such cases to the skillful use of these products. The persimmon and the banana as remedial and nutritive articles, are the most valuable fruits grown.

Value Of Non-Acid Fruits

Canned and evaporated fruits.

Raisins, prunes, figs, dates, apricots and peaches are common types of fruit preserved by the process of evaporation, and when soaked in clear water may be restored to almost their original condition. Evaporated fruit should not be cooked. This is perhaps the most palatable and wholesome method of preserving fruit. Next in purity and importance are the methods of canning, as practised by the housewife. The ordinary commercial preparations of canned fruits, together with the many jams, marmalades and jellies, are generally of doubtful, if not inferior quality. The Pure Food Law has accomplished much to establish honesty in the preserving and the labeling of food, but these products are still far from ideal, and are not to be considered where fresh or evaporated fruits are obtainable.