The outward appearance of the fruit is often a fairly reliable indication of the amount of sugar. Trielle has observed that fruits with yellow skins contain much sugar, and have a very penetrating odor. Fruits with red skins contain a medium amount of sugar, and have a pleasant, delicate perfume. Fruits with a reddish brown skin usually contain much sugar, and have very little perfume.
As showing its perfectly digested state, demonstrations have proved that fruit sugar may be injected directly into the blood, from which it will be utilized in nourishing the body. This is in marked contrast with ordinary cane sugar, which, if injected directly into the blood, is expelled through the kidneys, the body being unable to appropriate it as such from the blood.
Fruit sugar may be eaten in practically unlimited quantities. It supplies the body with heat and energy in the most available form. For this reason, fruit when eaten will quickly relieve the sense of exhaustion.
Fruit Acids
The acids of fruits give to them their delightful and appetizing flavors. Fruits in the unripe state contain tannic acid, a marked astringent. The gastric and peristaltic woes of the small boy the night following the green apple episode are due to the tannic acid the unripe fruit contains. The three chief acids of fruit are citric acid, found in oranges, lemons, and grapefruit; malic acid, as found in apples, pears, peaches, and similar fruits; and tartaric acid, as found in grapes. These are organic acids, recognized and readily digested by the body.
The acids of fruits are remarkable peptogens; that is, they stimulate the appetite and promote the flow of the digestive juices. Fruit acids are most efficient disinfectants. Some years ago, an eminent medical authority of this country, in a representative medical gathering, said, "We are as yet without a satisfactory medicinal intestinal disinfectant." In fruit acids, we possess such an agent in a most desirable form. No germ, disease-producing or otherwise, can live in the presence of fruit acid. Fruit acids can be taken practically ad libitum. Fruit acids taken freely by mouth or diluted and injected into the bowel, most efficiently asepticize the intestinal canal. Three or four pints of water to which the juice of one lemon has been added, injected into the bowel following a cleansing enema, will thoroughly destroy disease-producing bacteria in the colon. Flushing the bowel frequently with such a solution is one of the most efficient known means of successfully combating the fetid summer diarrheas of children.
The proteid or nitrogenous element of fruits, as well as their fatty element, may be passed over with little consideration. Fruit contains little proteid; and aside from the olive, there is almost no fat in fruit. The fat of the ripe olive, however, is one of the most delicious and digestible forms of fat. Ripe olives contain about fifty per cent fat. Olive oil can be mixed with water; therefore it readily mixes with the intestinal juices, and is most easily digested.
Fruit Salts