But the simple provision of the total sum of calories may by no means satisfy the real food needs of the population. For example, all the calories might be provided by potatoes alone, or grains alone, or meat or fats alone. But the population would starve under such circumstances. Food provides not merely the energy for the body, but the substances from which the body adds new tissue to itself during growth and reproduces its constantly breaking down tissues during all of life. Now while all kinds of food produce energy in greater or less quantity, only certain kinds are the source of new tissues. Hence there must be in the personal or national ration a sufficient proportion of the tissue-producing foods, the protein carriers, as well as a sufficient amount of the more strictly energy-producing foods, such as the fats and carbohydrates. And there is necessary, too, in any ration capable of maintaining the body in properly healthy condition, the presence in it, in very small quantities, of certain food substances called vitamines which have an important regulatory effect on the functioning of the body. These substances occur only in certain kinds of food. All these things had to be taken into account in the war-time handling of food. So important was a proper knowledge of scientific food use and application of this knowledge, in connection with the efforts of the various countries to feed themselves most economically and to best effect in the light of their possibilities in the way of food supply, that every country concerned called on its scientific men to advise and help control the obtaining and distribution of its national food supply. For example, America and the Allies (England, France, Belgium and Italy) established an Inter-Allied Scientific Food Commission composed of experts who met at various times at London, Paris, and Rome, and on whose advice the determination, both as to kind and quantity, of the necessary importations of food from overseas to England, France, Belgium and Italy was largely made. Thus the war has done more to popularize the scientific knowledge of food, and to put into practice a scientific control of food-use than all the efforts of colleges and scientific societies and food reform apostles for years and years before. Calories, proteins, carbohydrates, fats and vitamines have been taken out of the dictionary and put into the kitchen. [Illustration: Photo by P. Thompson A Community Conference on Food-Saving The importance of work of this kind increased after the signing of the armistice, because the Poles, the Belgians, and other peoples whom we could not reach during the war needed every pound of food we could spare.] GOVERNMENT REGULATIONS