In our climate but very few fresh vegetables can be had in winter. A few varieties of cabbage, like the red cabbage and possibly some few others, are to be had when the winter is not yet well advanced. Brussels sprouts, chicory and endive, etc., may often be obtained late in the autumn. Even in the middle of winter one may have fresh vegetables by growing them in a cellar, in which case one first spreads out a layer of earth, then some manure, and on the top another layer of soil. Such vegetables as do not absolutely require light can be made to grow well in a cellar, and some kinds, like the chicory and endive, even lose a part of their bitter taste. Certain fungi, like the mushrooms, can be planted in a cellar. The same is the case with salad, and usually the vegetables raised in this way are rather more easily digested, although they are poorer in some o,f the saltsiron, for instance. Naturally, the salad grown in the open is much better, particularly because of its high content of iron, 5.31 per cent., and other nutrient salts. It also contains 37.63 per cent. of potash, 7.54 per cent. of soda, the rather large amount of 14.68 per cent. of lime, 6.19 per cent. of magnesia, 9.19 per cent. of phosphorus, 8.14 per cent. of silicic acid, and 7.65 per cent, of chlorine.
Salad thus grown also contains acids, like citric acid, in combination with the potash. The amount of nutrient sub-stance is very small, and it has less of protein (1.92 per cent.) than the field salad (2 per cent.), but is generally more easily digested. The sugar content is only 0.11 per cent., and the other carbohydrates are likewise poorly represented, for which reason it may be freely eaten by diabetics. It is also useful owing to the salts contained in it, which have an alkalinizing action. Head salad when well prepared with good ingredients is a very good food in summer. It is more healthful when mixed with lemon juice than with vinegar. Nature has already provided it with some citric acid, and when a good vegetable oil, like olive oil, is added its nutritive value, which is really slight, is considerably increased.
In the heat of summer the fresh acid taste of such salad increases the appetite, and it is a useful adjunct to meat foods. We have already referred to other varieties of salad, like the endive, chicory, cress, etc., as well as tomatoes and cucumbers. As a salad vegetable we may also, mention the olive, which would prove very nutritious, owing to the oil contained in it, were it not for the fact that it is very indigestible. In some countries, as in France, Italy, and Spain, the olive is eaten at the beginning of a meal, as a “hors d’oeuvre,” for the purpose of stimulating the appetite. The olive contains barely i per cent. of protein, but rather more carbohydrate (9 per cent.) and a great deal of fat (18 per cent.). In salads it is especially important to use pure oil, with preferably lemon juice or the best vinegar.
Olive salad can always be used during the winter, the summer vegetables being also available when preserved. Naturally, preserved vegetables are never as good as fresh ones; the fine flavor is impaired, but the nutritive substances and nutrient salts remain when the vegetables are kept, together with the juice in which they have been cooked. The vegetable must first be cooked and then be placed in sterilized bottles or large jars. The neck is then hermetically closed with rubber bands between the lids and bottles, in much the same way as in the Weck process. This is probably the best method of keeping the vegetables. In the Weck method the vegetables are cooked in the bottles. In this way the majority of summer vegetables may be at our disposal in the winter, although they will have lost some of their taste. Unfortunately bought pre-served vegetables often have the disadvantage that injurious substances have been added in order to give them a fine appearance; thus, the peas and cucumbers have a wonderful green color. This is usually obtained by the addition of a very small quantity of copper sulphate or blue vitriol, and, although it is stated that experiments have shown that this is not in the least harmful to normal persons, the statement should not be depended upon. As we have shown in another portion of this work, the natural condition is always greatly to be preferred in everything, and, although such additions may not be directly fatal to life or to the health, the accumulation of such minimal quantities of injurious agents continued during a long time would probably prove injurious to the majority of persons. Even the vinegar in which some vegetables, such as cucumbers, beets, etc., are pickled may often be injurious, owing to the mineral acids contained in it. The mixed pickles of commerce are also very indigestible.