*Regulation of the Food Supply to the Cells.*—The storage of food materials is made to serve a second purpose in the plan of the body which is even more important than that of supplying nourishment to the cells during the intervals when no food is being taken. It is largely the means whereby the rate of supply of materials to the cells is regulated. The cells obtain their materials from the lymph, and the lymph is supplied from the blood. Should food substances, such as sugar, increase in the blood beyond a low per cent, they are converted into a form, like glycogen, in which they are held in reserve, or, for the time being, placed beyond the reach of the cells. When, however, the supply is reduced, the stored-up materials reënter the blood and again become available to the cells. By this means their rate of supply to the cells is practically constant. We are now in a position to understand why carbohydrates, fats, and proteids are so well adapted to the needs of the body, while other substances, like alcohol, which may also liberate energy, prove injurious. It is because foods are of such a chemical nature that they are adapted in all respects to the body plan of taking up and using materials, while the other substances are lacking in some particular. [Fig. 80] Fig. 80—*Diagrams illustrating the relation of nutrients* and the non-relation of these to alcohol. _A._ Inter-relation and convertibility of proteids, fats, and carbohydrates (after Hall). _B._ Diagram showing disposition of alcohol if this substance is taken in quantity corresponding to that of the nutrients (F.M.W.). The alcohol thrown off as waste is unoxidized and yields no energy. *Why Alcohol is not a Food.*—If the passage of alcohol through the body is followed, it is seen, in the first place, that it is a simple liquid and undergoes no digestive change; and in the second place, that it is rapidly absorbed from the stomach in both weak and concentrated solutions. This introduces it quickly into the blood, and once there, it diffuses rapidly into the lymph and then into the cells. Since the body cannot store alcohol or convert it into some nutrient that can be stored (Fig. 80), _there is no way of_ _regulating the amount that shall be present in the blood, or of supplying it to the cells as their needs require_. They must take it in excess of their needs, regardless of the effect, at least until the organs of excretion can throw off the surplus as waste. Compared with proteid, carbohydrates, or fats, alcohol is an _unmanageable_ substance in the body. Attempting to use it as a food is as foolish as trying to burn gasolene or kerosene in an ordinary wood stove. It may be done to a limited extent, but is an exceedingly hazardous experiment. Not being adapted to the body method of using materials, alcohol cannot be classed as a food.