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. 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. [Sidenote: Evils of acid fruit in northern countries] 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 fruits is added to the hydrochloric acid, of which most people have a deficiency, serious acid fermentation may result. Acid fermentation is the beginning of nearly all stomach trouble, and is the primary cause of many other ills. (See "Fermentation," p. 424.) [Sidenote: Value of subacid fruits] 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. [Sidenote: Value of non-acid fruits]