Group I. Apple, Pear, Quince

Good apples are a wholesome fruit. They are useful for their antiscorbutic and also for their laxative properties. They should be given to invalids only when cooked. When well masticated they are one of the best forms of fruits for children, being specially valuable for cleansing the teeth. They are better avoided by the diabetic. Crab apples are used to make a jelly, with a distinctive sweet acid taste and beautiful colour.

Pears and quinces are less digestible than apples, and should not be given to invalids.

Guavas are a wholesome and nutritious fruit. There are many varieties. In the tropics they are used largely, and they are imported into this country in the form of a table jelly.

Group II. Orange, Lemon, Lime, And Grape Fruit

Oranges and other members of this family are specially rich in free citric acid, and their chief value in therapeutics lies in their well-known antiscorbutic properties. Sweet oranges are eaten raw. Bitter oranges are used for making marmalade. When oranges or lemons are wanted for flavouring, as in Russian tea or lemonade, the juice alone should be used. Orange juice is laxative, especially for infants. Small unripe oranges, known as orange-berries, are used in making curacao. Lemon juice is useful in cleansing the tongue and assuaging the thirst in fevers. It is also of value for imparting flavour to otherwise tasteless foods, such as rice or barley water. (For Lemonade drinks, see p. 276.) Lime juice, sweetened and unsweetened, is used largely as a beverage, especially in warm weather The shaddock and grape fruit are useful for their laxative and slightly diuretic properties, when taken early in the morning. The somewhat bitter taste may be disguised by the addition of sugar and a little brandy.

Group III. Stone Fruits

Plum, Sloe, Damson, Greengage, Bullace, Peach, Apricot, Cherry, Olive, Date, and Prune. - Damsons, greengages, bullaces, and sloes may be regarded as varieties of the plum. Plums are a wholesome fruit when wholly ripe and not over-ripe. If consumed in the over-ripe or unripe state they are very liable to induce colic, diarrhoea, and other evidences of gastro-intestinal derangement. A special variety of plum forms, when dried, the medicinal prune. Common prunes are dried plums, and are largely used in desserts; they are useful for constipation. The ratio of sugar to free acid in plums is low, 1.6: 1, but in damsons it is higher, 7: 1.

Peaches, apricots, and nectarines do not contain so much sugar as apples and some other fruits, and are useful in diabetes. Peaches contain less than 2 per cent, of sugar. These fruits do not keep well; their juice has a distinctly laxative action in many subjects. Cherries, in this country, are eaten fresh, stewed in tarts, or preserved. Cherry brandy is made by mixing brandy with cherry juice. Maraschino is similarly prepared, specially fine sugar being employed in its preparation.

Dates are the fruit of the date palm. They rank in nutritious value with grapes; dried dates contain from 50 to 60 per cent, of sugar and allied substances. The fruit is eaten fresh or dried, and in the latter state is made into flour. It forms a staple article of diet to the Egyptians. Figs, though hardly a stone fruit, may conveniently be referred to here, since they rank with dates in nutritive properties. Dried figs are a highly nutritious carbohydrate food, containing from 50 to 60 per cent, of carbohydrate and 3 to 4 per cent, of protein.

Olives are little used in dietetics except as appetisers. The taste is an acquired one. Olive oil is largely used as a salad dressing.

Group IV. Acid Fruits. Grape, Gooseberry, Currant, Cranberry, Etc

Grapes are specially rich in sugar, in this respect resembling dates. The amount of sugar present is always high, and ranges from 10 to 30 per cent.; the ratio of sugar and acid in good grapes being 25:1; and in slightly sour grapes, 10: 1. The acid in grapes is mainly tartaric acid, combined with potash, lime, and magnesium. Grapes have laxative properties. The "grape cure" is sometimes employed for constipation and obesity (see p. 538). Raisins are dried grapes, and are prepared in two ways, the finest - Muscatels - being dried on the growing plant; other varieties - Uxias - being dried after collection.

Currants, raspberries, barberries, gooseberries, cranberries, blackberries, mulberries, all contain considerable free acid. The ratio of sugar and acid is, as a rule, about 4:1, and they are therefore eaten with sugar. They are used to make refreshing beverages, or to make jelly or jam.

These may be usefully employed, especially in the feeding of children. The fruits in the following section also come into the category of acid fruits.

Group V. Fleshy Fruits. Strawberry, Raspberry, Black-Berry, Mulberry

The ratio of sugar and free acid in strawberries ranges from 2 to 1 up to 7 to 1 in the pineapple strawberry. They are rich in potash and soda salts. When taken in moderation, they are a wholesome and very agreeable food. Many people have an idiosyncrasy against them, manifested by the development of urticaria or gastrointestinal trouble. Gouty subjects should partake very sparingly. Strawberries have special value in the treatment of sprue (see p. 369).

Group VI. Banana, Pineapple

Bananas are very rich in carbohydrate, and for a fruit contain also a high proportion of protein. A diet consisting solely of this fruit will maintain life for long periods. In its ordinary form, however, it is too bulky to serve as the staple constitutent of food. Dried bananas are now imported into this country, and form a pleasant, highly nutritious dessert food. Dried bananas are also ground into a meal or flour, which has valuable properties as a food. It can be made into a thin gruel or porridge, and when taken with cream is a very nutritious foodstuff. The cheapness of bananas is another point which adds greatly to their value as an important food. Torrefied bananas ground down make a coffee which is a wonderfully good substitute for ordinary coffee.

Pineapple is one of the less digestible fruits, on account of its fibrous nature. Its juice is pleasant and wholesome, and has the power of digesting protein. It enters into the composition of Mosquera's beef meal.