The fact that more oxygen is required for combustion of fat than of starches and sugars is an important item for those who wish to call upon the fats stored within the body for daily heat and energy and thus reduce in weight. If sufficient starches, sugars, and fats are not consumed in the food to supply the daily heat and energy released by exercise, the body calls upon the sugars and starches temporarily stored up and, when these have been consumed, upon the reserve of fat. If much fat is consumed in the daily food this fat in the blood will be oxidized before the fat stored about the muscular tissue. The scientific reduction of weight, therefore, lies in the regulation of the supply of starches, sugars, and fats consumed, and, the oxidation of more of these substances through an increase in the daily exercise. Deep breathing of pure air should accompany all exercises, to supply sufficient oxygen for combustion, or oxidation. Manual laborers require more fat for energy than do people whose habits are sedentary. School children, or children who play hard, should have sufficient fat, and where fats are withheld, sugar should be freely supplied. The supply of fat stored in the body depends upon the quantity consumed with the food, upon the quantity used up in heat and energy, in muscular exercise, or in mental force. The quantity thus consumed depends somewhat upon the condition of the nerves. If the nerves are weak, they do not properly direct digestion and assimilation and less fat is consumed in the digestive and assimilative processes. =Butter and Cream.= The fat present in milk depends, of course, upon the quality of the milk. There is as much butter fat in a glass of fresh Jersey milk as in a glass of cream, which has been separated, by machinery, from the milk of some other cows. The cream from some Jersey cows is almost all butter. Skimmed milk contains very little fat. If milk is drunk by the adult, as a means of storing up more fat within the body, the cream should be stirred into it. =The Fat of Meat= should be thoroughly cooked and cooked with moisture. All meats in the process of baking or frying should be covered, in order to retain the moisture. To make fat easily digestible it should be well masticated. Bacon, if fully immersed in its own grease, in the process of frying, is a common source of fat and is easily digested. =Cod Liver Oil= from the liver of the codfish, is more easily absorbed and assimilated than any other fat. The odor is not pleasant and a little lemon juice, salt, baking soda, or any substance for pungency and flavor, may be added to make it palatable. The pure oil taken in this way is perhaps preferable to the prepared emulsions. One has the advantage, at least, of knowing what he is taking.