o'clock in the morning is between 12 and 1 o'clock, for he will then be in need of food and if he defers his principal meal till evening he will be so tired that he can neither enjoy nor fully digest it. Such persons should eat a good breakfast, a full dinner about noon, and a supper between 5 and 6 o'clock. If their appetite for an early breakfast is poor, they should eat a light lunch about 9 o'clock A. M. and a similar lunch between 8 and 9 P. M. For persons not engaged in active muscular work it is desirable that they should eat a light breakfast, a hot lunch at noon, dinner at 5 o'clock and some light lunch between 8 and 9 P. M. Unfortunately, we possess as yet no reliable data, as regards the requirements of food for men who, while leading a sedentary life, perform a great amount of brain work. Some authorities claim that mental, like physical, labor increases the amount of carbon consumption, but not of nitrogen. Others insist that since the brain and nerve tissues contain the elements of nitrogen and phosphorus which occur in the protein compounds, they should be especially concerned in building up brain and nerves and keeping them in repair. The general impression, however, is that people whose work is mental rather than physical eat too much, especially fat and carbohydrates, and that the ordinary subsistence diet composed of 100 grams of protein, 56 grams of fat and 450 grams of carbohydrates is best suited for their wants. The food for all persons of leisure should be selected with a view of preventing overtaxing the digestive tract, and the production of constipation with its attending evils, such as pelvic congestion, enlargement of the liver, hemorrhoids and chronic dyspepsia. The legumes, coarse vegetables and clarets should be avoided, but the use of light dry wines, fruits, and coffee instead of tea may be encouraged.

The importance of a good set of teeth for complete mastication and avoidance of bolting the food, in order to secure thorough insalivation, has already been pointed out; nor should we underrate the influence of our frame of mind upon this important physiological function. Every meal should be a feast; the food should be temptingly served and monotony avoided; relishes and flavors should not be wanting. Pawlow, in 1902, has shown that the primary secretion of true gastric juice is the result of a reflex starting in the mouth and that the relish of the food originates the reflex. In other words, he has experimentally demonstrated why certain tempting dishes, however inexpensive, "make our mouths water," and Hornborg in 1904 has shown that distasteful food fails to cause gastric secretion.

GOOD FOOD AT REASONABLE COST.

BY C. F. LANGWORTHY, PH. D.

Expert in Nutrition, Office of Experiment Stations, U. S. Department
of Agriculture.

The human body needs food, air, and water for its growth and maintenance just as do all living things. An engine can not run a machine or draw a train unless it has fuel, which is converted into energy or, as we say, which is used to generate power. In the same way the body must have fuel for the work of all sorts which it performs, for instance, for the work expended by a mason in laying stone, or by a carpenter in sawing or driving nails, by a woman who sweeps or does her housework, or by a child who runs or plays, and the body must also have fuel for the work which goes on inside it, such as the beating of the heart, or the movement of the chest when we breathe, a sort of work which is less often thought about and so less familiar to most of us.

Everyone knows that a large engine requires more fuel than a small one and that if the work is severe more fuel is needed than is the case when the engine is simply running and little or no work is done. It is the same way with the human body. A large vigorous man needs more food than a small child or a woman who is not more than twothirds his size, and if a man or woman is engaged in severe work each needs more food than when idle, the need being manifested by "a better appetite." Age also has a decided effect on the kind and amount of food needed, an aged man or woman naturally requiring less food than a man in youth or middle life, since the daily tasks and the amount of work done gradually decrease until in extreme old age most of the time is passed in quiet. Soft foods and simple dishes are more suited to old age when teeth are few and body vigor is much less than in the prime of life than are the hearty foods which strong men and women need. The infant needs the mother's milk and later the simple foods-eggs, milk, bread, vegetables, cereals, fruits, etc., which are the best foods for childhood and are most certain to build up a vigorous body. As childhood passes, the mixed diet with which most of us are familiar is commonly followed and, all things considered, is doubtless the most satisfactory for ordinary persons in health. Such a diet is made up of vegetables, fruits, flour and other products from cereal grains, meat, fish, dairy products, eggs, and so on.

Many persons have an idea that there is some special food, some ideal

diet suited to each kind of work and to every condition of life and that if we possessed full knowledge of the subject it would be desirable to prescribe the daily fare with the same care and accuracy with which a physician prescribes his medicines, but this does not seem to be the case. We do not regulate with such exactness the work we do, the leisure we take, the amount of clothing we wear, and all other conditions of our daily lives, and so it is for our best interest simply to regulate our diet along general lines in accordance with good sense, economy, and the knowledge which has been gained from a scientific study of the subject, taking care that the different foods are so combined that all the needs of the body are provided for, that excessive waste is prevented, and that both undernourishment and excess or overeating are avoided.

It is essential that foods should be of good quality, clean and wholesome, and that they should be well cooked. The dishes that are most relished and the methods of preparing them will vary in different countries and in different regions of the same country, for each race, and indeed each region, has its favorite foods and its special methods of cookery. However, when the question of food is carefully studied we find that value of the diet expressed in scientific terms is practically the same the world over when we consider persons of like size and weight performing equal amounts of work. This means that just as an engine of a given size would require in China the same amount of fuel for a given work which would be needed in the United States, so the human machine in any part of the world requires the same amount of fuel, that is, food, for a given task which would be required in any other region.

With the engine it is immaterial whether the fuel be wood, coal, or anything else which is convenient provided the quality is satisfactory and the engineer knows how to use it. With the human machine it is something the same. All ordinary foods are useful when rightly combined and each country will naturally make use of the food supply which may be most easily and economically produced.

A study of the various materials which are used as food shows that they are composed of comparatively few constituents, namely, water, mineral matter, starch, sugar, and other bodies which are called carbohydrates, fat, and nitrogenous material commonly called protein, such as the white of egg and the lean of meat. The human body is made up of the same constituents. All of the body tissues contain the nitrogenous material, protein, which is similar to that found in the lean of meat, the white of egg, in gluten of wheat, etc., and so it is understandable that the body must be supplied with food containing nitrogenous material

enough for forming this tissue and for replacing any which, like the skin, finger nails, etc., may be worn away by the various conditions of our daily life and also for other purposes for which the body requires protein. In the case of the infant the nitrogenous material needed for body growth is supplied by the milk-a food comparatively rich in this. constituent as well as in the other nutrients. Later in life the nitrogenus material is supplied largely by milk, cheese, eggs, meat, cereals, beans and similar foods.

As has been said, men, the world over, of like size and performing like amounts of work apparently eat practically the same amounts of food when considered from the standpoint of its composition, and students of nutrition questions are very generally of the opinion that this fact is more than a coincidence and that these average quantities eaten actually represent average needs. Values deduced from such observations are commonly referred to as dietary standards, that is, guides for food management.

Expressed in its simplest terms, the dietary standard for a man of medium size, say 150 pounds in weight, in good health and performing a moderate amount of work, calls for 100 grams (or 3.5 ounces) of nitrogenous material (protein), and fat and carbohydrates enough to supply with the protein 3,500 calories of energy in the amount of food provided per day. There is always some waste in cooking and serving food and if we consider the food purchased the values are 115 grams protein (4) ounces) and 3,800 calories. These terms are unfamiliar to most persons and it is unfortunate that some terms which are more familiar can not be found, but it is true here as everywhere else that each subject requires its own terms. We can measure cloth by the yard or milk by the quart, but we must measure work by horsepower or electricity by terms which are even less familiar. Fortunately, in the case of food and diet the matter can be explained in other ways so that the results can be applied in home management without undue difficulty.

The housekeeper who wishes to estimate the nutritive value of the food she prepares, in order that she may conform with the suggested dietary standards, can readily do so by the use of such a table as the one here given, which shows the protein and energy value of the portions ordinarily served of the more common food materials, the values given being approximately only as it would be hardly desirable to state absolute figures for such a purpose as that for which the table is designed. The weights of the food portions included in the table are given in both grams, the unit of weight commonly used in scientific work, and in ounces, the more common household unit. To avoid unusual fractions

of an ounce the nearest 1⁄2 ounce or 4 ounce or some similar common fraction is used instead of more accurate equivalents.

In such a table the protein content of the food gives an idea of its relative value for building body tissue. The value of the food as a source of power for carrying on work is expresed by the energy it supplies when utilized in the body as fuel is burned under a boiler, and is measured as calories. A calorie is equal very nearly to 1.54 foot-ton, that is, it represents force which would be sufficient to lift one ton 1.54 feet and is a more convenient unit for such purposes than horsepower or other similar unit.

APPROXIMATE WEIGHT AND NUTRITIVE VALUE OF AN AVERAGE PORTION OF SOME COMMON FOODS.