Of the inorganic foods water may well take precedence in our discussion, because it comprises about sixty-six and two thirds per cent of the body. So much of the body is composed of water that it has been stated that we are still aquatic animals. Water is absolutely essential in the performance of every body function. One may do without the organic foods for many days or even weeks, but twenty-four hours without water will cause the victim to experience a thirst which soon becomes not only a desire, but passes beyond the stage of desire to a torturing longing for water, and this after two or three days merges into a suffering which nearly unseats the reason.

Water is used in the digestion of foods. While the water of digestion is frequently taken as drink during meals, it ought to be largely secreted by the salivary glands during the process of chewing; in order that these glands may secrete freely during mastication, one should drink copiously an hour or so before each meal.

Water is used also in the process of absorption of digested foods. Water makes up nearly ninety per cent of the circulating fluids of the body, thus making possible the easy distribution of food materials from the point where they are absorbed to the various parts of the body where they are assimilated by the tissues. Within each living cell of the body water is necessary to all the life processes. It is used by the glands in their elaboration of various products or secretions. For example, ninety-nine and one half per cent of the saliva and the gastric juice and about ninety-eight per cent of the pancreatic juice is water.

Man has in his ingenuity added many things to water, but, as a rule, these additions are useless, if not actually harmful. No drink ever devised by man has been more effective for the slaking of thirst than pure water.

It is hardly necessary to enumerate the sources of pure water. Springs and wells furnish a large proportion of the water in general use for domestic and dietetic purposes. Cities frequently take their water from rivers and lakes, adopting many devices to protect the original source from contamination through drainage from factories, houses, and barns, as well as to protect it from contamination during its passage through reservoirs and mains. Most of the water from the sources above mentioned contains a certain amount of mineral salts in solution, for the most part carbonates. When these mineral salts are sufficient in amount to cause any appreciable curdling of soapsuds, the water is said to be hard, while waters with too small an amount of mineral substance to cause any appreciable curdling of soap are called soft waters. Springs which issue from sand usually produce soft water. Wells which draw their water from between rock strata usually produce hard water, the water having taken up salts from the rock through which it has percolated. Rain water, being really distilled water, is soft when it first falls, though it may take up various salts and other impurities from the roofs and cisterns. These impurities may be in part removed through filtration.

The boiling of water not only kills all bacterial germs, but deposits a considerable portion of the carbonates from hard water. Almost any water not actually contaminated by putrefying animal matter can be made wholesome and satisfying by boiling and aerating. Boiled water that has not been aerated has an insipid taste, but if boiled water is cooled in a jar or bottle that has been filled to only one half or two thirds of its capacity, it may be aerated by thoroughly shaking the bottle or jar. This gives the water its original flavor.

The average person needs about two quarts of water in twenty-four hours. About half of this is taken with soups, fruits, vegetables, milk, and other foods, thus leaving, as a rule, only about one quart to take as beverage. This general average need of the body is greatly varied by weather conditions. On a hot, dry day one will drink very much more water than on a cool, damp day.

This requirement of the system is quite accurately indicated by the sense of thirst. This sense can be relied upon as a faithful guide to the individual as to the amount of water needed by the system. However, this sense, like all others, is subject to perversion. Many people accustom themselves gradually to the use of a very small amount of water, less than their systems really need. As a rule, most people use too little water. Such people are almost certain to suffer from constipation and various other disturbances, which they seldom attribute to their meager use of water. One of the most important rules in personal hygiene has to do with the use of water and is as follows: Arise at least three fourths of an hour before breakfast, drink two glasses of cold water; take ten minutes of brisk exercise in the open air, preferably out of doors. If not out of doors, then before an open window, filling the lungs full of fresh morning air, and repeatedly contracting and relaxing the muscles of the legs, arms, and trunk, particularly the latter.

One of the most important parts played in this morning exercise is performed by the water, which washes out the stomach, carrying its slimy accumulations down through the coils of the intestine, during the morning exercise, thus preparing, as well as inducing, a copious natural evacuation of bowels, usually before eight o'clock. No more important hygienic regime could be adopted than that outlined above to produce tonicity of the muscles, keen appetite, quick and complete digestion, complete and natural excretion of waste materials, a clear complexion, and clear lustrous eyes.

This is the regime followed by those world-renowned beauties who look thirty-five at the age of seventy, as well as by those husky octogenarians who swing an ax, a scythe, or a golf club with the vim and spirit of youth, notwithstanding the fact that they have passed the age that marks the senile decay of most men.

If a person is unable to take active exercise because of invalidism, the use of the water, and perhaps massage on the part of nurse or attendant, serves a most important substitute for the above outlined strenuous regime.

Inorganic salts may be discussed very briefly because the dietitian seldom has to provide for them separately. These substances are very important, the calcium salts making the substance of bones and teeth, while the sodium, potassium, and magnesium salts are used in the circulating fluids. However, the milk which forms the first food taken by all mammals, and the egg which is the food for young birds, contain all of these salts in the proper proportions and quantities. It therefore follows that when milk and eggs are used in the diet of older animals they furnish important sources of mineral salts. All vegetable and fruit juices likewise are rich in various salts. So are also the cereals, legumes, and nuts. It would, therefore, be impossible to devise a reasonable diet which would be free from mineral salts. The usual admixture of milk, eggs, vegetables, and fruits will in a vast majority of cases contain the proper salts in quantities sufficient to serve all the purposes of the body. Common table salt seems to be an exception to the general rule, so that a diet composed largely of vegetable products needs a small addition of sodium chlorid to bring up these elements to the full requirements of the body. Herbivorous animals seem to experience the same need, and they occasionally make long journeys to find salt. Stock raisers usually put salt where it is accessible to the animals. Salt has thus come to be used as a condiment, and in this capacity it is likely to be used in quantities much greater than necessary, and while any moderate use of it cannot be looked upon as deleterious, its immoderate use is certainly not to be recommended.

About the only inorganic substance to which the dietitian needs to give special attention is iron. This substance is essential in the making of red blood corpuscles. It sometimes happens that more iron is excreted from the body than is taken up from the foods. This condition is due to some disturbance of nutrition. This disturbance may be in the digestion, the absorption, or the assimilation, but wherever the disturbance is, the blood-making organs do not receive the necessary amount of iron, and as a result the formation of the red blood corpuscles is interfered with. The blood becomes poor in hemoglobin; the victim becomes pale. This pallor may become extreme, until it reaches a waxy whiteness. Naturally this condition can only be removed by correcting the nutrition when that is possible. While the details of this treatment are left to the physician, to the dietitian is frequently left the choice of foods. The yolk of egg is especially rich in iron. The reason for this must be evident. The iron in the egg yolk supplies that substance to the red blood corpuscles of the young chick. It seems, therefore, a rational practice in dietetics to seek this same source of supply when we wish to get iron to replenish the blood of any individual. In the use of eggs, therefore, for such patients, the yolks of two eggs might well be substituted for the yolk and white of one egg. A very good way to administer these egg yolks would be in the form of egg lemonade, using two egg yolks and the juice of half a lemon, with sugar to taste, water half a pint and iced.

Another important source of iron is to be found in lean meat, especially the highly colored, deep red meat of the better cuts of steak or mutton and the breast of wild game. A third important source of iron is to be found in the chlorophyll or green pigment of plants. This is usually served in a menu in the form of greens, as spinach, chard, etc. Lettuce, celery, and cabbage leaves have also a considerable amount of iron, but all of these vegetables are usually bleached out, and therefore have a smaller chlorophyll content, and with that a smaller amount of iron. It is better, therefore, to use the greens that have the deepest color. It is interesting to note in passing that the highly colored meat red as well as the highly colored plant green owes this color to a pigment rich in iron. The dietitian seeks this pigment to bring back to the cheek of his patient the ruddy flush of health which is also indicative of red blood rich in iron.