This section is from the book "Practical Dietetics With Special Reference To Diet In Disease", by William Gilman Thompson. Also available from Amazon: Practical Dietetics with Special Reference to Diet in Disease.
There is a group of vegetables of which lettuce is the chief type, the leaves of which are eaten raw. They are useful for their flavour and for the variety which they furnish in the course of a meal. They cannot be said to possess any nutrient value, but they are usually taken with vinegar and oil, and the latter is very nourishing. Since they contain little starch and practically no sugar, they may be allowed in the diabetic regimen.
Sorrel and cress, or peppergrass, are used in the making of salads, but less in this country than in Europe. Sorrel has a somewhat pungent or acid flavour, which is due to acid oxalates, and this fact renders it unfit for use by patients who are subject to attacks of gout and rheumatism or who have the uric-acid diathesis. A fatal case of sorrel-poisoning in a boy five years of age has been reported. To quench thirst, excited by eating a quantity of sorrel, he swallowed some soapy water, the alkali of which produced a soluble oxalate. A quantity of oxalic acid was found in the stomach.
Many other substances are mentioned in works on dietetics which are used in the making of salads or pickles and as relishes. They are antiscorbutic and serve to stimulate the digestive secretions and give a fillip to the appetite. Such are green peppers, capers, mint, tarragon (an aromatic Siberian plant), parsley, chervil, endive, chicory, okra.
Celery is a wholesome vegetable when cooked in milk until it is quite soft; but eaten raw it is stringy, and, as it has but little nutritive value, its use in that form should be discarded by invalids. Its aromatic flavour makes it very popular, and it furnishes a useful addition to a light luncheon with bread and cheese. It has acquired an undeserved reputation for use in rheumatism. "Celery salt" is an agreeable flavouring substance for soups and salads. Various preparations are made from the plant, which are sold by druggists as hypnotics. They are of no value.
Artichokes are a variety of thistle. They contain tannin and mucilaginous materials, but nothing of true nutrient power, although, according to Moleschott, they hold 17.75 per cent of organic matter.
Green artichokes when tender and thoroughly cooked are easily digested, but their cost in this country prevents them from being consumed except as an article of luxury. They may be given to some diabetic patients among the few vegetables which they can eat with impunity. Eaten raw, as they sometimes are in France, they are very indigestible.