—The kumquat is one of the smallest of citrus fruits. It stands as one extreme of that important family of which the grape fruit or pomelo represents the other. The fruit is oval in shape, about one inch in diameter, and is one and one-half inches long. It may be regarded as a dwarf orange, and was brought into the United States from Japan, although it is a native of China. The name—kumquat—is of Chinese origin and is intended to mean “Gold Orange.” The kumquat tree, under favorable circumstances, reaches a height of 10 or 12 feet and forms a compact, symmetrical, and handsome head. The pulp of the fruit is very tender and agreeably acid and the rind is spicy, as is the case with most of the acid fruits. It is not only valued as a fruit, but the tree is also highly prized as an ornament. Its beautifully colored fruit, in contrast with its green leaves, presents a most agreeable spectacle. It is grown in the United States principally in Florida. The composition of the kumquat is practically that of the orange.
Lemons.
—The citrus fruit, next in importance to the orange, if not more important, is the lemon (Citrus limonum). This fruit is grown extensively in the United States in the same localities that produce the orange, that is, chiefly in Florida and southern California. Its method of cultivation, general treatment, time of ripening and harvesting are the same as that of the orange. Its principal difference from the orange is in its greater acidity and in certain peculiarities of its aromatic and oily substances. From the rind is produced an essential oil which, while resembling that of the orange in general character, has distinct properties which easily discriminate it from the orange product. The lemon also has a correspondingly less proportion of sugar than the orange. In 22 analyses of California lemons they were found to contain 5.26 percent of acid and only 2.33 percent of sugar. The distinct feature of the lemon, therefore, is its acidity. The principal acid present in lemons is citric acid, though other organic acids are also found. The acids are either free or in combination with a base, the principal base being potash. On account of its high acidity and low sugar content the lemon is used more as a relish and in the manufacture of acid beverages than directly as a food. There are some varieties known as sweet lemons which are eaten as oranges or used directly for food purposes, but generally the lemon is too sour and acid for consumption in this manner.
Lime.
—A species of citrus fruit which is even more acid than the lemon is known as the lime (Citrus hysrix acida).
Limes are not eaten directly as food on account of their high acidity, but their expressed juice is sold throughout the world for beverages and medicinal purposes. The lime also yields an essential oil, which is very similar in character to that derived from lemons. In fact the lime may be regarded as a very sour lemon, just as the orange may be regarded as a very sweet one.
Adulteration of Lime Juice.
—Unfortunately lime juice is offered on the market often in entirely spurious forms, that is, a mixture made up with flavoring of an acid character resembling that of the natural juice. The natural juice is also frequently adulterated by the addition of preservatives. Among these, sulfurous and salicylic acids are perhaps the most frequent. Lime juice can be perfectly preserved by sterilization, and there is no necessity for the use of preservatives therein.
In the tropics there is also found a lime of a saccharine character known as the sweet lime, but this fruit does not have a very great vogue.