in great esteem by the ancients. In 1520 it was introduced into England from Flanders. There are many varieties, some of which are spreading, and have large succulent leaves, while in others the leaves are drawn together similar to the cabbage and are crisp and nearly white. The varieties may be classified as (1) cabbage or head lettuce, (2) "Cos" or leaf lettuce, named from the Island of Cos, near the coast of Greece, and (3) cutting lettuce from which the leaves are cut as they mature.

There is not much food value in the lettuce, although its mineral salts may be of use in the processes of metabolism. Some ascribe medicinal virtues to the lettuce on account of its containing a small quantity of a sleep-inducing substance called "lactucarium" which is found more abundantly in the stem. Others have recommended it' for supplying iron in the organic form, as some believe this element is in this plant chemically combined in the chlorophyl. As a wholesome, cooling, agreeable salad plant, lettuce has always been a favorite throughout temperate and semitropical countries.

RADISH (Raphanus sativus)

The radish, although its root is the part generally used, may be classified here, as it is seldom eaten in any other way except raw and as a salad. This plant was originally grown in India, and later introduced into Great Britain and the United States. Many of the edible varieties are small and quickly grown; but large radishes are also used. One of the winter radishes, a Japanese variety, sometimes attains a length of 2 feet, and is a foot in diameter. It is commonly cut in chunks and pickled in brine. The radish has a somewhat pungent taste, and is valuable as an antiscorbutic.

MISCELLANEOUS SALAD PLANTS

Other salad plants are the cardoon, which is something like the artichoke, the leaf stalks of which are blanched like celery, 1 Human Foods, Snyder, p. 42.

which is eaten as a vegetable in soup or as a salad. It grows in the countries which surround the Mediterranean. The tender leaf stalks of several varieties of thistle are used as food in some countries, and the young leaves and stalks of the mallow. The finochia (sweet fennel) is a favorite salad plant in Mexico. The stems are blanched like celery.

Other plants of this group, some of which have vegetable acids or essential oils which give them a characteristic flavor, are borage, burnet, cress, water-cress, cowslip, corn salad or Lamb's lettuce, caper, chevril, mint, nasturtium, parsley, pepper grass, peppers (green), sorrel and tarragon.

AROMATIC AND MEDICINAL HERBS

The following aromatic and medicinal plants, although not properly belonging to the class of foods, are often used in foods for flavoring or garnishing, and may be grown in the vegetable garden: anise (seeds), balm (leaves), caraway (seeds), catnip (leaves), coriander (seeds), dill (seeds), horehound (leaves), hyssop (leaves), lavender (flowers), parsley (leaves), rosemary (leaves), rue (leaves), sage (leaves), saffron (flowers), savory (leaves), sweet basil (leaves), sweet fennel (seeds), sweet majorum (leaves), sweet thyme (leaves), wormwood (leaves).

For description of the most important of these see Spices and Condiments, p. 440.

CHAPTER VII

LEGUMES (Leguminosa)

The legumes,1 or pulses, as they are called in England, stand next in importance to cereals among vegetable foods. They include beans in great variety, chick peas, peas, lentils, peanuts and a few other plants. They have been in use for so many hundreds of years and in so many countries that their origin is lost in antiquity. In China, India, northern Africa and other countries bordering on the Mediterranean Sea, they have formed an important part of the food of the common people for centuries.

The plants of this family all have a characteristic papilionaceous or butterfly-shaped flower, and the seed grows in pods, containing sometimes few and sometimes a large number of individuals. Many of these plants are broad-spreading trees, which yield fruit entirely inedible for man, but most of those bearing edible fruit are low and herbaceous.

Perhaps the most interesting characteristic of the family is, that many of the plants not only furnish a valuable food, but at the same time actually increase the fertility of the soil in which they are grown. This is due to the fixation of atmospheric nitrogen by the bacteria working unceasingly in the laboratories of the root nodules. It is only within the last sixty years that these facts in regard to the soil-fixation of nitrogen2 have been understood, although the practice of plowing under cow peas, clover and similar crops has been common for many years.

Beans and peas mature rapidly, and therefore can be grown in the northern countries, as three or four months only are needed to bring them to full maturity. They are cultivated as garden

1 U. S. Dept. Agri., Farmers' Bull. No. 121.

2 U. S. Dept. Agri., Farmers' Bull. No. 315.

crops, and have the advantage of not requiring any special kind of soil and indeed they will not refuse to grow and produce a fair crop on comparatively poor soil. This is largely due to the fact that they can avail themselves of a double supply of nitrogenthat which is contained in the soil as nitrites, nitrates and ammonia, and that which is collected from the air by the root nodules.

Since protein food is usually expensive it would seem that in beans and other legumes we have found a cheap and abundant source of this kind of nutrient, and to a certain extent this is true, and beans have been extensively utilized for this purpose. It happens, however, that the protein exists in the legumes in the form of legumin with but little albumin. As has been pointed out by Voit, vegetable foods in general are less completely digested than animal foods, and this legumin is acted on mainly by the ferments which work in alkaline solutions, especially in the lower part of the alimentary system. On this account, then, beans are not readily digested in the stomach, although they are absorbed by the intestines.

Nutritive Value

Numerous experiments1 have been made to find out to what extent the protein of beans, peas, etc., is actually utilized as a nutrient in the human system. Some of these experiments seemed to indicate that there was a much greater waste of protein than when meat or wheat was used as food, but later results show that, with certain limitations and precautions, the protein of the legumes is fairly well digested. The legumes do, however, require more work by the digestive tract than many other foods. If beans or peas are ground before being cooked, the absorption of protein is more complete. It is also well established that if they are combined with other foods, and do not form too large a proportion of the diet, the nutriment is much more completely utilized than when they are used alone. In comparison with other vegetable proteins, the legume proteins are less well utilized.2

1 Human Foods and Their Nutritive Value, Snyder, p. 72. 2 Jour. Biolog. Chem., Vol. 10, p. 457.

The flatulence that is often occasioned by the use of a diet consisting largely of beans is probably caused by the breaking up by bacteria in the intestine of the germ of the bean, giving rise to a considerable quantity of the hydrocarbon, methan (CH4).

Legumes as Food

It is true that beans form an admirable and cheap addition to the food of persons engaged in manual labor, and persons exposed to severe weather, for in lumber camps and mining regions they are used in great quantities and with little discomfort. Under such conditions, a pound of baked beans per person a day produces no ill effects. People of sedentary habits, however, are not able to digest large quantities of leguminous foods, and whenever these foods are used an abundance of other nutrients should be eaten at the same time.

Says Hutchinson, in speaking of the pea and bean,1 “As a cheap and efficient method of supplementing the deficiency of nitrogen in a purely vegetable diet, however, their use is strongly to be recommended, and it is a pity that they are not more largely taken advantage of by those to whom economy is of importance, for unquestionably the pulses are among the cheapest of foods, and a given sum will yield more protein, if invested in these, than in any other way." As the legumes when ground into flour furnish a more digestible food than when used whole, it is rather remarkable that this product is not more generally placed on the market.

BEANS

The bean on account of the numerous ways in which it can be prepared for food, and because it is so readily grown, is one of the most important of the legumes. It is believed that beans were cultivated by the Indians of both North and South America, 1 Food and Dietetics, p. 224.