Green vegetables are even less nutritious than roots,, and are chiefly valued for their mineral salts, especially salts of potassium, and as a source of ballast, their indigestible residue stimulating intestinal movements. These vegetables contain about 90 per cent, of water and only from 1 1/2 to 3 per cent, of nitrogenous matter, probably only half of this consisting of protein (see table). In addition they contain cellulose in large amount, chlorophyll, sugars, gum, pectin, and sometimes traces of fat.
Calories per lb.
Lettuce . ...
Rhubarb . ...
Spinach . ...
The young vegetable has a bitter flavour and is more digestible than an old one. As age advances they become tough and stringy from the increase in cellulose. Their digestibility is increased by careful cultivation in suitable soil. They should be eaten fresh, for owing to the large quantity of water which they hold, they soon dry when stored, and so loose their freshness. Celery and winter cabbage are exceptions, as they may be kept for weeks. Before use they should be carefully cleaned, not only by removal of dead and decaying parts, but by careful washing and soaking in salt and water: the latter to kill any embryos of tapeworms, etc.
Vegetables as a whole are not very easily digested, on account of the large amount of cellulose. In the process of cooking, vegetables gain much water and lose some of the carbohydrates and proteins, and much of their salts. As the nutritive value and digestibility of vegetables depend largely on their careful cooking, and special attention should be directed to this, a short account of the best methods of preparation is given later (p. 122).
The Cruciferae tribe of green vegetable, to which the cabbage and its varieties belong, furnish a large proportion of the vegetables for table use.
There are many varieties, but they all contain a large quantity of sulphur, which tends to cause flatulence, hence they are not suitable for invalids. When fresh and tender, cabbage is a wholesome food for the healthy, and has decided antiscorbutic properties. When young, they can be eaten raw with vinegar. They may be used in broth, or boiled and made into a puree.
Cauliflower is the flower of a variety of cabbage grown large and tender by cultivation. It is one of the most easily digested green vegetables. It is boiled and eaten with white sauce or cheese sauce; or if shredded down and dressed with vinegar and oil, it can be added to salad, and it is also used as a pickle. Broccoli is a variety of cauliflower, but inferior in flavour.
"Greens" or Kale have open heads' of leaves. German greens are the most delicate. They should be boiled and mashed like cabbage.
Seakale are the tender young sprouts of the sea cabbage grown in the dark, so that there is no chlorophyll. The presence of the green colouring matter gives a disagreeable acrid taste. When properly cultivated they are as easy to digest as the cauliflower.
Brussels sprouts are clusters of leaves resembling miniature cabbages growing in the axils of the main leaves. They are very nice when thoroughly cooked.
Savoy is another variety of cabbage.
Sauerkraut, a German dish. The leaves of the white cabbage, when fully grown, are taken out, layers of salt laid between them and pressed; this bruises the leaves and squeezes out the juice; it is then set aside until fermentation commences. It is generally eaten boiled, like fresh cabbage.
Celery is much cultivated for the blanched leaf-stalks or for the root. It is eaten raw, alone or in salad. It may be cooked in milk and used as a vegetable, or used in the flavouring of soup. It can also be made into a puree, and used as celery cream.
It is not easily digested, but Its aromatic flavour makes It very popular. Celery salt and celery seeds are much used as flavourings. It has a great reputation for rheumatism; the reason for this is not quite clear.
A cultivated thistle. The heads are cut before they expand. They are either boiled or eaten raw with salt and pepper. The vegetable contains tannin, and is easily digested, but has a curious flavour and is not in common use.
Asparagus is considered a great delicacy, and was even cultivated by the Romans. There are two varieties, white and green - the green is probably the finest. This vegetable possesses a very delicate flavour, and is much appreciated by invalids. The seeds are sometimes used on the Continent instead of coffee. The ingestion of asparagus has a diuretic effect, largely increasing the quantity and imparting a strong and disagreeable odour to the urine; it appears within one hour after it is eaten, and may persist from twelve to twenty hours. It is due to a sulphur product, a methyl mercaptan which is formed in the intestine during digestion and is excreted by the urine.
Spinach is a favourite vegetable, but contains no nutriment. It is used for improving the complexion, and it is certainly of benefit in relieving chronic constipation. If the leaves are young and tender, and if they are cooked until they are quite soft and then rubbed through a sieve, it is a very easily digested vegetable.
"Beet tops" turnip tops, and dandelion leaves can all be used in the same way as spinach.