The alkali, Soda (sodium), which is most necessary in the body for the proper constitution of its fluids, is derived chiefly from animal foods, this being taken in the chemical form of chloride of sodium, or common salt; whilst the alkali Potash (potassium), which is essential for the renewed construction of cells, perhaps also of the red blood corpuscles, and of the muscles, is got more abundantly from the vegetable group of foods. Green vegetables, and ripe fruits are a particularly valuable source of potash salts. A craving for table-salt as an addition to the diet specially prevails among vegetable feeders. If it be wished, by the use of alkalies, to prevent the gouty formation of uric acid sediments, as gravel, and the like, or to gradually dissolve such concretions as have already become formed in the bladder, it will certainly be more rational to prescribe a diet of fresh fruits, potatoes, and other such vegetable products than to order alkaline mineral waters, or medicines, which, if taken constantly, are likely to create all kinds of irritative disturbances in the blood.

Speaking generally, it is not to the laboratory of the chemist we should go for our potash salts, but to the laboratory of nature, and more especially to that of the vegetable kingdom. They exist in the green parts of all vegetables; but we wastefully extract a considerable proportion of these salts when we boil the vegetables, and throw away their potage, which our wiser and more thrifty French neighbours add to their everyday menu.

When we eat raw vegetables, as in salads, though, not converting their starch elements into soluble dextrin, especially if vinegar is added, yet we obtain all their potash constituents. Fruits, taken generally, contain important quantities of potash salts; and it is upon these vegetable products that the likely victims of gouty acid formations should especially rely; lemons, and grapes contain the same most abundantly. It should not be forgotten that nearly all the chemical compounds of potash, as they exist in fruits, and vegetables, are acid. But these organic acids become disintegrated in the body by their combustion, and then leave alkaline residual bases. Far different is the case with vinegar, and the mineral acids, which are of fixed chemical composition, and remain acid throughout.

Mattieu Williams teaches, in his Chemistry of Cookery (1898), that the saline constituents of vegetables (which are usually boiled out in the cooking water) are absolutely necessary for the maintenance of health; without them we become the subjects of gout, rheumatism, lumbago, gravel, and all the ills which human flesh, with a lithic acid disposition, is heir to. The potash of these salts existing in the vegetables, as combined with organic acids, is separated from these acids by organic combustion, and is straightway presented as an alkali to the baneful gouty acid of the blood, and tissues, the stony particles of which it converts into harmless, soluble lithate of potass, and thus enables them to be carried out of the system by the urine, the skin, and other channels. "I know not which of the Fathers of the Church invented fast days, and sowpe maigre, but I can almost believe he was a scientific monk, and a profound alchemist, like Basil Valentine, who, in his seekings for the "aurum potabile," 'the elixir of life, had learnt the beneficent action of organic potash salts on the blood, and therefore used the authority of the Church to enforce their frequent use in vegetable foods among the faithful." The proper compounds to be produced are those which correspond to the salts existing in the natural juices of vegetables, and in flesh, viz., compounds of potash with organic acids, such as tartaric acid, which forms the potash salt of the grape; such again, as citric acid, with which potash is combined in lemons and oranges; likewise malic acid, with which the same alkali is combined in apples, and many other fruits; similarly, too, the other natural acids of vegetables in general, as well as the lactic acid of milk.

As long as the human body remains alive a continuous state of slow combustion goes on within its economy, gradually, and for the most part gently, during which the organic acids of these potash salts become slowly consumed, whilst giving off their excess of carbonic acid, and water through the outlets of lungs, skin, and kidneys, but leaving behind their alkaline potash. This potash combines with the otherwise stony lithic acid (gouty material) just when, and where it begins to be harmfully formed, and neutralizes it into a soluble innocent combination. But no such happy decomposition is possible with free mineral acids in the blood, and tissues, to wit, sulphuric, nitric, or hydrochloric (if given medicinally), which are therefore poisonous to persons of a gouty, lithic acid disposition. Neither does the acid of vinegar - acetic, produced by fermentation - become changed so as to yield an alkali against gouty deposits; but, as already stated, lemons, and grapes contain the fruit salts of potash most abundantly.

Persons who cannot afford to buy these fruits as daily food may use cream of tartar, which, when genuine, is the natural salt of the grape.

Again, we shamefully neglect the best of all food by failing to partake more freely of fruit when ripe and sound. If it must be had cooked, then what we have to say is, "Jam for the million, jelly for the luxurious, but fruit-juice in some form for all." The desire among boys for fruit, which sometimes tempts them to rob the orchard, is due to the craving of nature at this time of life for vegetable acids, a craving which it is needful to gratify, and wrong to deny.

The chief mineral substances necessary in food are soda, potash, lime, magnesia, and iron, together with phosphorus, chlorine, sulphur, and traces of such matters as silica, fluorine, and iodine. These constituents are of vital importance as structure-builders, and renovators. Lime and phosphorus are organically combined in milk; iron in yolk of eggs, meat, and artichokes; sulphur in all vegetable nitrogenous foods. Of dietetic articles the richest in lime is milk, next eggs, then the cereal grains, especially rice. Iron is present (as to order of richness) in spinach, yolk of egg, beef, apples, lentils, strawberries, white beans, peas, potatoes, and wheat. Milk, and its derivatives, such as cheese, are very poor in iron. Of vegetable foods, oatmeal, and Egyptian lentils are amongst the richest in iron, but bread, rice, artichokes, potatoes, and spinach also contain a good proportion.