The fatty portion of our food is derived from both animal and vegetable sources, but far the larger portion is from the animal kingdom. Butter is probably the most pleasant flavored and popular of the animal fats, and commands a high price simply because better flavored and possibly more easily assimilated than most other animal oils. Olive oil holds a place among vegetable oils similar to that occupied by butter among animal fats. Some vegetables contain much oil, and large sums of money and much time have been expended in endeavoring to prepare them for culinary purposes.
Each fat, whether animal or vegetable, has a flavor peculiar to the animal or vegetable from which it is derived, hence in selecting fats for cooking food, as in frying and sauteing, we must choose fat which will combine harmoniously with the food to be cooked. In frying food in deep fat, the temperature of the fat has much to do with the food retaining its natural flavor, or taking the flavor of the fat in which it is cooking. If the fat is very hot when the food is put in, it does not impart its flavor to the cooking food. The odor of hot fat penetrates all parts of the house, and for this reason it is best to have, if possible, an odorless fat; in any case, we must have a pleasant odored one. It is generally believed that fats of vegetable origin will bear a higher heat without burning than animal oils will. Manufacturers have made great efforts to so deodorize fats as to render them fit for all culinary purposes, such as making cakes, etc., but so far thee are few, if any, that are entirely free from their natural flavor. Vegetable oils are usually liquid at all ordinary temperatures, while many animal oils are solid or semi-solid. Lard leaves a coating on the outside of food cooked in it, and mutton or beef tallow cools quickly, leaving a tallowy taste. Beef and lard are better mixed than either alone, for many purposes.
To prevent fats, either animal or vegetable, becoming rancid, they should be kept in a cool place. All bits of fat from the kitchen, except those which are highly flavored, as mutton fat, turkey fat, ham fat, etc., may be mixed and cooked slowly over the fire until they cease to bubble, then strained through cheesecloth, and used in cooking, greasing pans, etc.
U. S. Dept. Agr., Farmers' Bulletin No. 122; pp. 16 and 17. Food Products of the World - Green ; Johnston's Encyclopedia; U. S. Dept. Agr. Farmer's Bulletin No. 121.
In the combination of foods we have striking illustrations of the necessity of exercising both science and art in cookery. By art, we mean the disposition or modification of things by human skill, to answer the purpose intended. In order that the food fulfill its mission in the best manner, it must be palatable, digestible, and of such quantity and quality of nutrients as will meet all the demands of the system. The diet must be sufficiently varied to prevent its becoming distasteful. Each meal must be so ar-ranged as to not tempt those at the table to overeat.
The stockman devotes much time, thought, skill, and labor to ascertaining the best combinations of food for the domestic animals under his care. He first studies the composition of feeding stuffs, both what he calls rough-age, as hay, etc., and those which are termed "concentrates," as corn, oats, and such things. Experimenters ascertain the average coefficient of digestibility of these different food nutrients. This accomplished, they find the nutritive ratio, that is, the ratio which exists between the amount of digestible protein in a given feeding stuff, and the amount of digestible carbohydrates and ether extract which it contains. While the chemist and physiologist were ascertaining these things by analytical work and di-gestion trials, the stockman has been conducting feeding trials to determine how much protein, carbohydrates, etc., are. required to properly nurture farm animals under various conditions.
We, who are interested in the best rations for human beings, must master all these questions, and more than these, with human foods. Such things as the difference in the digestive apparatus of different persons, the effect of exercise and of rest, the consequence of the different modes of preparation of food, the effect of flavoring materials and beverages taken with our meals, all complicate the problem very much. There is still another point of difference. The ox will eat his portion of hay day after day in contentment and happiness. When the ox has no labor to perform, the stockman needs to give him no further attention than to furnish him a maintenance ration. It is not so with any specimen of the genus homo yet discovered. Even when he has need of no further food than the amount necessary to enable the heart to force the blood currents through the body, and give the digestive and assimilative organs power to do their work, if he only sits and breathes, he craves and needs, and perhaps demands, a variety of food.
Those who carry on digestive experiments on human beings say that they find it practically impossible, often, to carry on such an experiment longer than two days, because a single food, no matter how palatable at first, becomes so repugnant to the subject. Dr. Livingston, the African explorer, says: "Experience proves that the Europeans have greater endurance than the hardiest of the meat-eating Africans." Another argument in favor of varied diet. It is claimed that too great sameness, long continued, leads to an impairment of the digestive organs. All this evidence leads to the belief that the desire for variety of food is based upon physiological grounds.
For our present purpose, general principles applicable to all classes of people will be considered. Those questions which each person must settle with his own stomach must be considered and studied by each woman who has the special cases to deal with. Few courses in a meal are far preferable to many courses for several reasons. Such a meal affords sufficient variety to meet the idiosyncracies of different members of the family. It gives a sufficient amount of the different kinds of food to meet the demands of the system. It gives an opportunity for greater variety at different meals, and prevents one so soon tiring of any certain kind of food. It also relieves very much the tendency to overeat. Three or four courses are usually quite enough for a family dinner. It is very often well to begin both dinner and lunch with a soup. Whether the soup contains much or little nutrition should govern, to some extent the remainder of the meal.
In planning a meal, it is necessary not only to decide what food materials will furnish the needed nutrients in right amounts to meet the demands of the different members of the family, but we must see that we do not choose too many foods that are slow of digestion, nor too large a number that digest very easily and quickly. When foods are improperly combined, some portions are not digested and assimilated fully, and as they lie in the digestive tract unused, poisonous products are liable to be produced. "A daily ration consisting of milk, oysters, and rice would contain all the nutrients required by the body, and would be of about the proper bulk required for a ration, but if a laboring man were fed on such a diet for a long time he would experience hunger, because the foods are so easily digested that the digestive organs would not have enough to do. A ration consisting of roast pork, hard tack, bread, beans, skim milk, cheese, and olives would be exceedingly slow of digestion. This ration would contain all the nutrients required by the body, but discomfort would be experienced by many if they attempted to digest such a ration."*
The way in which improper combinations of food affect the cost of the nutrients is illustrated in the following:
"Dietary studies were carried on in the families of a teacher and of a tinner living in Lafayette, Ind., during the spring of 1895. An examination of the details of the two studies shows that the teacher's family obtained per man per day 75 grams of protein and 1,425 calories of energy at a cost of twelve cents; the tinner, 62 grams of protein and 1,640 calories of energy at a cost of thirteen cents. In other words, the actual nutritive value of the diet was not notably different in the two cases. The proportion of beef, veal, eggs, etc., in the two diets, was, however, quite different. The teacher's family used large amounts of beef round, shoulder, and some loin steaks, which were purchased at low prices. The tinner's family used rather less beef, but the cuts that were used were, on the whole, more expensive. The teacher's family used more veal, which was relatively costly, less eggs, more than twice as much milk, and less butter than the tinner's family. On the whole, the former got a little more protein and a little less energy than the latter in the animal foods purchased.
"However, the great difference in the two dietaries lies in the kind of cereal foods purchased. The teacher's family had home-made bread and cakes, while the tinner's family bought bakers' bread, and occasionally cakes. The former obtained his bread at about one-half the cost to the latter, even when a reasonable allowance is made for the cost of all the ingredients in the bread, and the heat required to bake it. The teacher's family used more •cereals and less vegetables and fruits than the tinner's family. In these ways, the former family obtained in their vegetable foods 36 grams of protein and 1,485 calories of energy for six cents per man per day, while the latter spent more than twice the amount (thirteen cents) per man per day, and obtained 44 grams of protein and 2,200 calories of energy. In other words, the teacher obtained for eighteen cents as much protein and nearly as much energy as did the tinner for twenty-six cents."*