December, 1926
ISDCSTRIrlL A S D ENGINEERING CHEXISTRY
knowledge of foods and nutrition gained through the chemical research of recent years, and that this mill bring to a much larger proportion of all people that full measure of health and efficiency which only the mo3t fortunate now enjoy. Perhaps deserving of special emphasis is the fact that, under the guidance of our present knowledge of foods and nutrition, it is entirely feasible so to improve the utilization of the primary crops now produced as t o make them pro7Tide both better nutrition and for larger populations than a t present Of course, this is not true to so great an extent in the older and more thickly populated countries as in the younger countries which are not yet thickly settled; but the difference is only one of degree Everywhere it is true that the grass and grain which are being turned into meat would yield several fold more human food if turned into milk instead. The energy and protein of the material eaten is much more economically converted into human food by the milch cow than by the animal which is fed merely for slaughter, and what is now seen u i t h special force is that the conservation of the vitamins and mineral elements so important to the human food supply is incomparably more efficient in the conversion of feed into milk than into meat.
1263
This is not t o suggest anything like a cessation of meat production, but only its intelligent moderation. I n a paper recently read before the British Association for the Advance ment of Science, this resource is recognized, but in what seems to be too reluctant and pessimistic a way. As reported in the daily press, the English speaker linked this suggestion with that of the saving of the waste now incurred in the use of grain to produce alcoholic beverages and added: “I feel that the race, noi the individuals, which cuts our meat and alcohol in order to multiply is of a permanent slave type, destined to function like worker bees in the ultimate community.” But is the drone a higher ensample than the worker? And as to slavery, might it not be a t least equally logical to hold that a people who would deny existence to descendants yet unborn rather than moderate the consumption of alcohol and meat are perhaps making themselves slaves to their palates? Is there not more to commend the more optimistic view that as people come to understand the possibilities opened by our present knowledge of foods and nutrition they will find satisfaction in acting upon them, both for their own and for the public good?
The Present and the Future of the Food Supply’ By E. B. Forbes INSTITUTB OF ANIXALNUTRITION, PENNSYLVANIA STATE COLLEGE, STATE COLLEGE, PA.
OOD is the most urgent requirement of life, and the food supply the basic problem of Civilization. From our American point of view, one aspect or another of the food problem has been to the fore, in our public consciousness, from the first winters spent by our European ancestors on this side of the Atlantic to the winter just past, in which the economic status of the food producer was one of the most insistent problems before Congress. Especially during the last quarter-century has our attention been called to matters of food and nutrition. Greatly stimulated by the revelation of conditions within the food industries which led in 1906 t o the passage of the national pure food law, our interest has grown apace through a revolution in our understanding of the principles of nutrition, through vast extension of mass production, marketing, manufacture, preservation, and transportation of foods, and particularly through the prominence recently given the subject of food in war, and of “a place in the sun”-that is, a place to produce food, as a cause of war. It will be readily understood that the food problem is in reality two-one having to do with kinds of foods, and the other with amounts.
F
Qualitative Aspect of Food Problem
I n a critical sense there are no essential foods. Only specific nutrient constituents of foods are essential. I n dietary terms, therefore, there are many roads to correct nutrition; in d ~ i c hsense, in spite of the differing food customs of the peoples of the world, the food problem is fundamentally and universally but one and the same. I n this light x e have come to understand that, from the point of view of the natural selective determination of nutritive requirements, during the evolution of the human 1 Presented a t the Round Table Conference on “The Role of Chemistry in the World’s Future Affairs,” at the Sixth Session of the Institute of Politics, XVilliamstown, l f a s s . , August 18, 1926.
species, the most important changes which man has made in his diet have been, first, the cooking of his food, and second, since yesterday he became a farmer, the adoption of cereals and cereal foods (including sugar) as the foundation of his ration. These two innovations have been prominent factors in the development of civilization, but have brought in their train a group of physical afflictions comprising the great qualitative food problem. We know something of the effects of cooking, both desirable and undesirable-to make foods easier to masticate; to make foods more palatable; to make some foods more digestible; to sterilize foods; but also to reduce the vitamin contents of foods; to develop in many foods a pasty condition resulting in adherence to the teeth, and the development of injurious acid fermentations on the teeth. Honeever, in spite of some important contributions, comparatively little scientific study has been given this problem of fundamental effects of cooking. A great flood of new scientific evidence, however, has shown in detail the nutritive deficiencies of the cereals and cereal foods, and has shown, especially in view of their quantitative predominance, that they constitute a distinctly disturbing and unbalancing element of the diet of most, a t least, of civilized mankind. Milk, meats, nuts, eggs, fruits, and leafy vegetables are each notable as contributing factors of safety-of nutritional insurance-to the diet. Some authorities on nutrition do not list meats with the protective foods, but the recent evidence on the protein values of foods, and on their effectiveness to support reproduction, lactation, and blood regeneration, requires that we consider meats, especially the glandular organs, as characterized by important protective qualifications. The common deficiencies of cereal foods-possessed by individual products, of course, in varying degree-are especially in mineral nutrients, vitamins, and the quality of the proteins. Sugar is characterized by all these deficiencies,
I N D U S T R I A L A N D ENGINEERIXG CHEMISTRY
1264
and white flour and polished rice by most of them. The liberal use, therefore, of these and other foods of cereal origin places upon us a burden of duty to restore the nutritive balance of the ration by the selection of other dietary components, in the light of their nutritive qualifications-an obligation which, we must admit, we fail, on one account or another, entirely to satisfy. Data on Food Production and Consumption in U. S.
As a basis for further observations we shall now consider the materials for nutrition which are available in the United States. Pearl2 classifies food products, in consideration of their economic status, as primary and secondary. Primary foods are foods derived from vegetable crops and aquatic animals; secondary foods are those derived from domestic animals. The significance of this distinction is that, as compared with primary foods, the secondary represent a loss of a very large part of the nutrients of agricultural origin used to produce them. During the seven years from 1911 to 1918 the total of primary and secondary food produced in the United States was distributed as follows: Protein Fat Carbohydrates Calories
Primary foods Per cent 51 17 94 59
Secondary foods Per cent
49 83 6
41
The fact that such an impressively large proportion of the total food production of the country is in the form of the relatively uneconomic secondary products of animal origin signifies that, in the present state of development of our agriculture, there is an enormous conservation function to be performed by domestic animals-a conservation of roughage, milling, and manufactory by-products, farm wastes, and cereals not wanted for human food. These data, i t will be understood, apply to production only. Pearl computes that during the six years from 1911-12 to 1916-17 the people of the United States consumed 48 per cent of the total calories of their diet in the form of grain foods, plus sugars-a fact of tremendous dietetic significance, in view of the nutritively unbalanced character of these products. The distribution of protein, fat, carbohydrates, and calories of the total of primary and secondary foods consumed during the years 1911 to 1918, in terms of percentages of the total caloric value of the diet, was reported by Pearl as follows: Protein
Fat
Carbohydrate Calories
Primary foods Per cent 47 18 95 61
Secondary foods Per cent 53 82 5 39
The average daily consumption of nutriment per adult man in the United States was computed by Pearl to be 120 grams of protein, 169 grams of fat, and 541 grams of carbohydrate, with a total energy value of 4288 calories; which figure was reduced, by allowance for edible wastage, to 3424 calories for ingested food. A nation consuming 53 per cent of its protein, 82 per cent of its fat, and 39 per cent of its energy as secondary foods has not been obliged seriously to consider the necessity of rigidly economic nutrition; and the amount of the average total ration leaves no question as to the sufficiency of the diet as a whole. Factors in Local Food Problems
The food problem in any particular region is influenced largely by the prevailing system of farming, as determining the foods available and as determined by a great complex of factors such as the following: fertility and depth of the soil, and the surface configuration of the land; conditions as to 9
“The Nation’s Food,” 1990.
W.B. Saunders Company.
T’ol. 18, No. 12
temperature, rainfall, and length of growing season; adaptation of the soil and climate t3 individual crops, especially grass; plant and animal pests, parasites, and diseases; prevailing methods of utilization of roughage, surplus grain, and milling and manufactory by-products; method of maintaining the fertility and the organic matter of the soil; method of distribution of labor throughout the year; food habits of the people; transportation and marketing facilities; power and labor conditions, tariff restrictions, availability of capital, cost of land, and amount of public taxes. Academicians have been known to introduce confusion into considerations of the food problem by failing to realize the great complication of conditions which determine systems of agriculture, and therefore foods available, and by basing recommendations upon single factors. Whatever the prevailing system, i t may be considered as a n expression of the local idea as to that which will yield the greatest profit per man, from the acreage, equipment, and capital available. Possible Competition between Man and Animals for Food
One of the measures of the successful feeding of the human family is that i t be accomplished without the depletion of man’s primal heritage-the fertility of the soil. Various methods of maintaining fertility have been evolved in different countries, but very generally, especially among Aryan peoples, the most practicable and profitable system involves the extensive employment of farm animals, to convert foods not available or not wanted for human use into food products of the highest type, at the same time yielding residues of great value for fertilizing purposes. Thus the food problem of the world is intimately bound up with considerations of systems of agriculture, and with the use of the several kinds of farm animals as converters and as producers of foods. Prominent, therefore, in all discussions of the economics of the food supply is a consideration, on the basis of chemical evidence, of the terms upon which domestic animals produce human food and, on this basis, the extent of the alleged or possible competition between human beings and farm animals for food. Such discussions are apt to result in most misleading conclusions, if these be based upon the amounts of feeds consumed as compared with the immediate food products, since animal production holds its own, not through any such simple relationship, but by virtue of a great complication and diversity of considerations. Notwithstanding the many sides of this problem, however, and the many advantages of a system of agriculture involving extensive use of domestic animals, the general truth prevails that dense populations turn away from those types of animal production requiring the use of the largest land area, toward the more intensive types of animal production, as indeed also of other food production, and especially toward an increasing use of vegetable in place of animal foods. To a large extent, at least, this becomes a matter of necessity. The extent to which this eventual necessity to increase the proportion of the primary vegetable foods in the diet will be a disadvantage, and a misfortune, is a most intricate problem, regarding which no one is now in position to speak dogmatically. In this relation we must distinguish clearly between present and future possible competition between human beings and domestic animals. To illustrate this distinction, let us compare meat, of any sort, with milk, peanuts, soy beans, or cottonseed flour. I n the light of their chemical composition these foods are all potentially close competitors, because they are nutritively capable of serving many of the same functions. At the present time, however, their actual competition is very slight,
December, 1926
IArDUSTRIilL A N D ENGINEERIiVG CHEMISTRY
because we do not wish to use them, and are not obliged to use them, for the same purposes-even in so far as we might effectively do so, in view of their similar chemical composition. But in the future increasing density of popul:ztion, maydoubtless will-require that we use these foods a t least more n a l y in the ultimate, truly economic manner. At the same time, the full realization of the nutritive possibilities of the less palatable foods will be delayed in accord with our economic ability to express our natural dietetic preferences. I would insist, however, that the truly economic place of animal production in the system of agriculture is much broader than many peoples unacquainted with the rearing of animals, and with the handling of animal products, have made it; and the idea of competition between men and domestic animals has been very greatly exaggerat'ed, by some writers, through discussing the subject as though the utmost, eventual competition prevailed today; while, as a matter of fact, to my mind, not only is there, at this time, no such competition, but animal production should be credited with very extensive and important services of conservation, of foods either unavailable or undesired for human consumption, and with contributing to the diet foods of the highest types, not only as to nutritive value, but also palatability and general dietetic usefulness. Armsby computed that the farm animals of the United States consume about 3.9 times as much food, on an energy basis, as do the people; that three-fifths of the food given to animals consists of grains; and that this three-filths, in grains, has an energy value two-and-a-third times as great as that of the aggregate human ration. It would appear, therefore, that the difference, in food, between the efficient and the careless feeding of the farm animals would feed the whole human population, and, further, that we pay an enormous price, in terms of food energy, for the animal foods that we eat. I n view, however, of the fact that the food which these animals eat is comprised of products which human beings either cannot eat or do not want, it is necessary to consider animal production in a broad and general way, as justified by a great complication of conditions, and especially as accomplishing most important food and fertility conservation functions. Relative Economic Efficiency of Different Animals
But in spite of these considerations, it is .obvious that the relative efficiency of animals to convert feeds into human foods, and the relative extent to which the different kinds of animals eat foods which human beings could eat, in case of necessity, constitute a most important question in relation to human living. Let us consider some representative fragments of the evidence available in this field, but realizing that many of the comparisons made are fundamentally illogical because of the implication of' a nonexistent equivalence of economic status. Thus, in comparing the economic efficiency, as food producers, of the cow, the steer, the sheep, and the hog, it is impossible to make proper allowance for the facts that the cow is fed very largely indeed upon the products of farmed land; that the steer is fed largely on roughage which is unavailable, or is not wanted, for milk production; that the sheep lives largely on unmarketable roughage, and at the same time grows a fleece; while the hog gleans his living to a large extent from the droppings of cattle. But the uncomparable must be compared. Cooper and Spillman3 computed estimates of the human foods produced from an acre of crops fed to livestock, and also from an acre of various crops consumed directly for human food. On this basis Indian corn is shown to be the a
U.S. Dept. Agr., Farmers' Bull.,
811.
1265
most efficient of our field crops, with potatoes, small cereals, and leguminous seed crops following in the order mentioned; and each of these primary food crops nahrally makes much more economical direct use of the land than does any type of animal production. Among the kinds of animal food product.ion, dairying leads, on this basis, but with pork production in the same class, while the production of beef, mutton, and poultry seems to make much less efficient use of the products of an acre of cultivated land. Such comparisons, however, are exceedingly unsatisfactory and deceptive, because of various untrue implications. Armsby4 states that the recovery of energy, available for human nutrition, of grain fed to hogs is 24 per cent; if fed to a milch cow the recovery is 18 per cent; and if to beef cattle or sheep, 3.5 per cent. Trowbridge, Moulton, and Haigh5 report experiments showing the gross efficiency of eleven beef steers. The two animals most nearly representative of commercial beef production exhibited gross efficiency of 9.6 and 8.3 per cent, respectively. These figures must be reduced by 30 to 60 per cent to allow for parts not eaten. Haecker6 reported experiments with forty-five steers, fed in fourteen lots, showing a variation of gross efficiency between 8.3 and 9.6 per cent. These values happen to be identical with the two noted from the work of Trowbridge, Moulton, and Haigh. The gross efficiency of dairy cows, to produce milk, is indicated by experiments of Eckles,' in which the recovery of feed energy averaged 16.9 per cent. This, of course, is entirely available for human food. On this basis, therefore, though it is evident that on broad agricultural economic grounds the comparison is unfair to the beef animal, the dairy cow possesses a several-fold advantage as to efficiency of production. Swine, however, on an energy basis are more efficient producers of edible food than is even the milch cow. The high efficiency of swine is indicated by experiments of Swanson,* in which t.wenty-six pigs were fed on various types of rations. The average gross efficiency of the sixteen animals which received corn and a protein supplement was 35 per cent. The reduction of this percentage, to allow for inedible parts, would be slight, as compared with the similar figure for beef cattle; and on this basis would make the hog appear to be nearly twice as efficient as the milch cow, and many times as efficient as the beef animal. The great advantage of the hog, in this relation, is due to his extensive feed consumption, to the concentrated nature of the feed, to the thick flesh and light bone of the carcass, to the small proportionate loss in killing, and to the slight waste in use of the fat of the carcass for human food. The Food Supply Becomes a Chemical Enterprise
A review of the situation as to the manufacture and preservation of foods must impress one with the phenomenal recent increase in the number and variety of products, with the corresponding opportunities for the selection of the diet; with the increased requirement for knowledge of foods and nutrition; and with the fact that a fully developed food industry is now largely a chemical enterprise. Consider, for instance, the meat-packing industry. I n addition to scores of products and by-products largely mechanically prepared-such as sausages and canned meats, meat extract, wool, bristles, curled hair, horn and bone manufactures, gold-beaters' skins, gas-proof skins for use in airship construction, surgical ligatures, and musical instrument strings-the packing industry turns out the following prod4 Science, 46, 160 (1917). 5 6
7 8
M o . Agr. Exp. Sta., Research Bull. 56 (1922).
Minn. Agr. Exp. Sta., Bull. 193 (1920). Mo. Agr. Exp. Sta., Research Bull. 7 (1913). J. Agr. Research, 21, 325 (1921).
1266
-
INDUSTRIAL AND ENGINEERING CHEMISTRY
ucts involving more extensive employment of chemical methods. or chemical control of physical methods, of production: leather (acid-tanned and oak-tanned), animal feeds, cooking fats, oleomargarine, lubricants, soap, glycerol, gelatin, glues of many kinds, bone black, calcined bone, ink, serum albumin, shoe polish, straw board, digestive enzymes, bile salts, insulin, adrenaline, thyroidin, pituitrin, extracts of pineal body, corpus luteum, and ovaries-and fertilizers, manufactured from fat-rendering residues, blood, meat and bone scrap, intestines, condemned carcasses, and gelatinmanufactory residues. Consider also the chemical products and processes involved in the fruit industries: the fertilizing of orchards; the spraying or fumigation of the trees; chemical cleansing of fruit to prevent decay in shipment; the bleaching of drying fruit and the fumigation of dried fruit; the control of canning processes, to preserve color, flavor, and vitamin contents; the manufacture of pectin (for use in jelly-making); the preparation and clarification of fruit juices; the manufacture of vinegar, essential oils, and fruit acids, and their salts; control of ripening in storage; coloring of citrus fruits in storage by treatment with ethylene; control of ventilation in storage and shipment; manufacture of animal feeds and fertilizers from fruit waste products. The entire milk industry is chemically controlled. Thus, the cow feeds are purchased on guaranteed chemical composition; rations are compounded in chemical terms; the quality of the milk, as to bacterial content, is determined by a chemical test; butter, ice cream, and four hundred varieties of cheese are sold under chemical control of fat content; casein manufactures in considerable variety are chemical products as ais0 are some synthetic baby foods based upon milk. Chemistry is also prominently involved in the manufacture of products of cereal origin, especially of sugar, and products of brewing and distilling. The blending of flour, the baking industry, and the manufacture of breakfast foods are chemically controlled. More than one hundred commercial products are said to be made from Indian corn alone. A recent venture in bread manufacture seems worthy of special comment. I n consideration of the well-known nutritive deficiencies of white wheat bread, George S. Ward carried out, under favorable conditions of scientific cooperation, a n extensive research having for its object the manufacture of a bread so composed as to correct these deficiencies. I n brief, the deficiencies of white wheat bread being due to its conditions as to protein, vitamin, and mineral nutrients, its status in these regards was rectified by the use, in its composition, of liquid milk and additional dried milk, inorganic salts, butter, oleo oil, and a protein-vitamin extract especially manufactured from wheat germ. This study was highly successful, the nutritional evidence being derived from extensive feeding experiments with small animals, carried out in triplicate, and confirmed by a longtime dietary experiment with children. This bread was a complete and balanced food in the sense of being able, supplemented only by water, to sustain normal growth and reproduction in laboratory animals through many successive generations-a most notable and, so far as the writer knows, unparalleled achievement. Unfortunately, the product fell into an unfavorable business situation before the problem of marketing it was fully solved, and it is not now being manufactured. The eventual success of the idea behind the product, however, of turning the most disturbing element of our diet into a complete food, and therefore a stabilizing dietary component, seems assured. For the present the net result of this venture is a general stimulus to the use of milk instead of water in bread-making; also there seems to be promise that another similar bread, utilizing
Vol. 18, No. 12
yeast, in quantity, in place of the wheat-germ product of the Ward bread, will soon be on the market. The public aspect of such a synthetic food project is important. As publicists should we approve of a “complete” bread, or should we withhold this approval in view of the fact that the wise selection of standard foods will providoall dietary essentials? The writer’s personal reaction is that the convenience of being able practically to assure the nutritive balance of the diet, through the bread, and the benefit which would thus accrue, especially to that large class of the population which is with most difficulty reached by nutritional education, constitute abundant warrant for a friendly interest in such a commercial product. It may be, however, that i t will prove more difficult to sell such a bread to the man who needs it most, a t a price allowing the necessary profit, than to reach him effectively with information as to correct choice of foods. This remains to be seen. Especially in relation to processes of preservation is food production a chemical industry. A recent development in this field is the cooperative trade association, through which small producers, as well as large, receive high-class scientific advisory service, directed toward the standardization of products a t the highest practicable level. Foods are preserved by storage, refrigeration, dehydration, chemical treatment, fermentation, hermetic sealing, and sterilization. Obviously, chemistry must control these processes, since the method employed is determined by such characteristics of the foods as moisture content, soluble matter in solution, hygroscopicity, temperature a t which to be handled and stored until used, and chemical reaction as to acidity or alkalinity. Refrigeration, the use of which is being vastly extended in food storage and in the shipment of foods the world around, is a chemical process. Chemistry is being used to study the respiration, and the ventilation requirements of eggs, fruits, and vegetables, and to control the ripening of fruits in storage. Food spoilage, due to chemical or other agencies, may be controlled by chemical or other treatment. Such spoilage may be caused by oxidative or enzymatic changes in sterile materials; to the growth of organisms in products stored under unfavorable conditions; to the becoming rancid of products rich in fat, especially if exposed to warmth and air; to the hygroscopic character of dehydrated eggs, milk, and vegetables; to colloidal changes produced by conditions of storage, in bakery goods, confectionery, and fruit juices; to light as an accelerator of chemical changes, especially of oxidative or enzymatic nature; to contamination by metallic containers, due to acidity, alkalinity, or intimate chemical composition of the product; to temperature changes; and to insect infestations. For the improvement of preserved food products there has been an extensive replacement of metal-lined by glass-lined cooking receptacles. Many critical and detailed chemical studies of processes and products are being conducted. New methods and new combinations of old methods are being used; for instance, a method for the sterilization of fruit juices without loss of flavor, by treatment with oxygen under pressure, has been developed. The exhaustion of the air from cans, or the replacement of this air by inert gases, is coming into extensive use, especially in the export trade Milk, preserved by cold, is now being shipped hundreds of miles in glass-lined vacuum tank cars, thus greatly extending the area of profitable milk proctiudon. Dehydrated milk and eggs have become standard products. The preservation of vegetables by dehydration has passed the experimental stage, and great expansion in the use of these dried vegetables awaits only the development of commercial demand, from
December, 1926
INDUSTRIAL A N D ENGINEERING CHEMISTRY
situations to which they are especially suited, and the adoption of the supplementary preservation processes required by their hygroscopic character. Among the live problems, on which further evidence is being sought, are the effects of preservation on the vitamin values of the products; means of retaining as much as possible of the color and flavor of preserved products; the prevention of the formation of hydrogen sulfide in some fish, meat, and vegetable products; prevention of the reaction of certain products with the metal containers, with resulting discoloration, and generation of hydrogen; and prevention of the deterioration of some products due to the presence of oxygen in the cans. Looking toward other possibilities of improvement of the diet through applications of chemistry in food industries, the use of cottonseed, soy bean, and peanut products as components of wheat bread has received some, and merits further, experimental study. Artificial butter will doubtless come to be generally improved as to vitamin content by apparently practicable methods already proposed, or by other similar procedures; and the increase of the antirachitic value of foods by irradiation may become a standard procedure in food manufacture. Ways will be found for deriving greater benefit from the nutritive superiorities of the glandular organs of nieat animals; and grester value will be derived from the protein of skin and bone, which we use as gelatin, when we have learned with what foods to use it to make good its amino acid deficiencies. The nutritive values of plant foods may be enhanced by selective breeding, a possibility which has been demonstrated in the development of the sugar beet and in the selective breeding of Indian corn for high and low fat and protein contents. Doubtless, also, we shall come to make greater use of the synthetic capacities of the lower organisms, such as bacteria, yeasts, and fungi, for purposes such as vitamin and protein production. Thus, partially hydrolyzed yeast has an attractive meat flavor; yeast can be grown on synthetic products; its protein is nutritively “complete;” it grows with marvelous rapidity; and recent, improvements in methods of growth of yeast have so cheapened the process as to promise great increase in the use of yeast as food. I n general terms, food manufacture and preservation have vastly improved the prevailing diet by providing for the better distribution of foods throughout the year, and, through the lessening of the labor in the home, have made an important contribution t o the emancipation of womankind. Also, the prevailing high morale in the food-manufacturing and preserving industries has especially favored the development of international trade in food products, which is noteworthy as a means of world-wide distribution of the materials for efficient and agreeable human nutrition. Conclusion
I n conclusion, the food problem is fundamentally one, the world around, in spite of differences in dietary detail; and, with increasing density of population will demand increasing attention as a part of the price of peace. I n the United States there is as yet no general quantitative food problem; ours are the qualitative food problems of great prosperity. These are the results (1) of the predominance in the diet of nutritively unbalanced foods of cereal origin, including a superabundance of white flour and sugar, which, collectively, are responsible for a great complexity of nutritional disorders, and (2) of the cooking of our food, which, in spite of important advantages, decreases vitamin values, and produces changes in the diet which are distinctly unfavorable to the hygiene of the teeth. The nutritive balance of the diet may be restored by the
1267
judicious selection of fruits, leafy vegetables, nuts, meats (especially glandular organs), eggs, and milk. At the present time there is no competition between man and the domestic animals for food in this country; the animals perform a definite and most important service of conservation, of foods either unavailable or unwanted for human consumption. With the tightening of economic conditions, however, as we approach the limit of population, we shall have no choice but t o increase the proportion of vegetable foods in the diet, and to discontinue the raising of cattle for beef alone; shall make increasing use of dual-purpose types of cattle; and eventually may have to depend for our beef solely upon that resulting as a by-product of the dairy industry. Pork and poultry products, however, seem to be assured to us in considerable quantities for all time by the efficiency of swine and fowls in the utilization of foods, and especially by the advantageous peculiarities of their food habits. It is obvious that there is a limit to the number of people which can subsist upon the earth, and that with continuously increasing populations there will be increasing pressure for land and for food. I n meeting this world food and population problem there are three alternatives which will appeal variously to different peoples in accord with their means, their temperaments, and their abilities. These alternatives are starvation, warfare, and the attainment of an equilibrium between births and deaths a t a population level allowing adequately for variations in food production. We are already familiar with many instances of starvation by millions; and have still fresh in mind the greatest combat of history, which impressed upon us the facts that while national nutrition has not been, by itself, the direct cause of recent wars, food is so prominent among human requirements as usually to be, in the last analysis, among the causes of war, and to be ever present among deciding factors in the conduct of war and in the making of peace. There can be no satisfactory final solution of the food problem until it is settled, together with the population problem, for the world as a whole, in accord with the third alternative, on the basis of an approximate equilibrium of population. There is absolutely no question but that, in time, there will be world-wide checks to the present rate of population increase. The only questions are as to whether they are to be accomplished by orderly and peaceable means, or by starvation, disease, and warfare; and as to the extent to which they are to be accomplished in such manner as to permit the survival of the superior types of mankind. The attainment of desirable ends in this greatest test of civilization will be facilitated by international good-will, flowing from international well-being. Whatever the nature of the differences between nations, these are accentuated by marked differences in the prevailing planes of nutrition. It is difficult for an undernourished man to be fair with one who dines in luxury. Bn old saying has it that “an empty stomach has no conscience.” From the point of view of practical world politics, therefore, the nutrition of the world as a whole is every nation’s problem, the solution of which will be favored by international organization, by the most extensive interchange of foodstuffs, and especially by the promotion of international fellowship in science and education, in all its diverse manifestations, as a means of helping every nation t o help itself. When we shall have been so fortunate as to attain a permanent population status, in a manner permitting the selective improvement of the human stock, and to have solved the problem of physical living in a finally economic manner, our minds will be freed for their own higher problems-for the development of a mental, a moral, a spiritual superiority beyond even our present conceptions.
