Fresh air, pure water and clean food are more essential for nutrition than any special selection of foods. The surroundings and in stincts of a people lead them to adapt their diet to the climate. In the tropics fruits and vege tables are the main sources of subsistence, in arctic regions foods are chiefly animal and value. Medical authorities on dietetics have laid much stress upon the choice of foods, but hard ly enough upon their preparation. A piece of meat or a*vegetable, however innocent in itself, may be ruined in cooking, while one of doubtful value, by right processes of cookery, may be come harmless and even useful. This is equally true from the economic standpoint. Count Rumford found that °the richness or quality of a soup depended more upon the proper choice of ingredients and a proper management of the fire in the combination of these ingredients, than upon the quantity of solid nutritious mat ter employed; much more upon the art and skill of the cook than upon the sums laid out in the market.° The nutritive qualities of many foods are doubtless made more available by a wise use of flavors, which in themselves con tain little or no nutriment. Condiments and spices, tea and coffee and the extractives of meats are of special value for the flavor which they impart. The cheap substantial.grain foods after all provide the larger part of the food of the human race and are made palatable by changes in flavors.
The hours and arrangement for meals have an influence in the assimilation of food.
Breakfast in America is a more substantial meal than it is in Europe, perhaps from climatic con ditions. The midday dinner seems best adapted to children and invalids, the night dinner is a concession to the competition of business. One dietetic authority estimates that more than half of the day's ration of protein and fat and one third of the carbohydrate is taken at dinner. Therefore the hour of the meal should be such as to provide for a period of rest afterward. The savage gorges himself when food is abund ant, then sleeps like an animal. The gourmand of classic days took an emetic to relieve his stomach that he might partake of delicacies yet to come. The best thought of the present day tends to shorter menus and simpler compounds, toward living and high Dietetic theories vary from age to age be cause of imperfect knowledge of bodily proc esses, or because of changes in the production and preparation of foods. Water, for example, was once excluded mainly from the dietary of patients suffering from fevers, and its use re stricted in other cases. Now it is recognized that a lack of water in the diet is a serious error and that many of our foods as served are not sufficiently diluted with water. In the past an exaggerated nutritive value was ascribed to beef tea and to gelatine, but later investigations show that the one should be classed as a stimu lant and the other not so much a real food as a protein sparer. There is yet much discussion
as to the relative value of whole wheat and white flour. The former is probably better for young children, because it supplies bone-mak ing material, but by modern methods of milling most of the nutritive material in the grain is retained in the best grades of white flour. The natural instinct of children for sweets has been repressed, but now sugar is recognized as a val food, provided it is taken at proper times. Oysters are less nutritious than is popularly supposed, and as ordinarily cooked are not es pecially easy of digestion. Combinations of foods often produce different effects from the separate ingredients, and small quantities of cer tam things may be helpful where larger quan tities would produce bad results. A food may be nutritious, economic in the true sense, and prepared in such a way as to be easily acted upon by the digestive organs and yet fail of perfect assimilation because it does not suit the habit or whim of the eater. In popular estima tion a food is digestible when no feeling of dis comfort follows after eating it, or when it is easily and quickly digested. The scientist con siders a food digestible in proportion as it is completely digested, whether the time be shorter or longer. Persons in health should consume some foods that digest slowly and beware of de pending upon pre-digested foods. If allowed to be idle, the stomach, like any other organ, soon finds it difficult to work.
The seven ages of man described by Shake speare might illustrate the different periods of hfe calling for a change in diet.
The infant thrives and grows on a diet of milk. When the mother cannot supply a suffi cient amount, clean milk from a healthy cow, by dilution with water or whey and by modifi cation with milk and cream, may be adapted to the increasing needs of a baby as it develops. Greater cleanliness in collecting and transmit ting milk to consumers. is a first requisite for the diet of young children. Defective nutrition causes indigestion, rickets, intestinal catarrh and many disorders of childhood.
The schoolboy requires abundant food from which to construct his rapidly growing body and to provide energy for his active exercise. With him quantity is often more important than quality, while his sister, enjoying less active sports, is over-fastidious. Dainty children and excessively greedy ones both are usually ill fed. Nervous diseases of children, even stammering, will yield to more careful diet. Milk, fruit, cereals, whole wheat bread, eggs and vegetables should form the bulk of the diet of school children. The school luncheon now receives considerable attention from educators.