A study of food composition and values will enable the housewife so to plan her meals that the various elements may be served to her family in the proper proportions. A knowledge of calories, and an intelligent application of the principles involved in these questions of nutrition, will enable any housewife to reduce the cost of feeding her family from twenty-five to fifty per cent, which would be worth while from an economical standpoint, not to mention the advantage to be realized healthwise. _Vitamines_ Says Lusk, "It has thus far been shown that nutrition means fuel for the machinery, new parts with which to repair the machine, and minute quantities of vitamines, which produce a harmonious interaction between the materials in the food and their host." In the words of another investigator, "The study of dietetics from the standpoint of the vitamines has only just begun." Sufficient has been learned and demonstrated about them, however, to show that they play a most important part in nutrition and in vital tissue processes. Since they are so little understood, a complete definition is not yet possible. The pure vitamine, it seems, cannot be isolated, so their exact chemical nature is not known. The chemical process necessary to free it is no sooner begun than the vitamine is apparently decomposed, and all trace of it is lost. One is reminded of the efforts of some early investigators to submit living protoplasm to a chemical analysis, they hoping thereby to reveal the mysteries of physical life itself; but at the first intrusion, this subtle something flees, taking its secrets with it, and leaving us only the empty shell of dead protein matter. While the activities and manifestations of life are seen on every hand in animal and plant, we are but little the wiser as to what life really is. Vitamines seem to stand closely related to the living process in the tissue cells. Some investigators have thought them to be the mother substances of the various bodily ferments and internal secretions, any disturbance of which produces serious constitutional troubles. Therefore the continuous use of a diet lacking in any of these mother substances would of necessity lead to a deficiency of these absolutely essential vital secretions and ferments. _Vitamines and Disease_