_Eggs._--Among the most delicate, digestible, and nutritious of all foods we may place eggs. Though somewhat more digestible when raw, they agree, as a rule, even with the most fastidious stomach, however cooked, even when hard-boiled. Eggs lend themselves readily to the formation of many delicious dishes, such as omelets, souffles, etc.; but unfortunately they do not contain nutriment in a very concentrated form, and where an adult is living on them alone it requires from one and a half to two dozen daily to furnish the necessary amount of food. _Fats._--Under the term "fats" are included all oily substances, such as butter, lard, olive and cotton-seed oils, and to a great extent the fat contained in meats. These substances are closely related to starches and sugars, and undoubtedly play a more or less similar role when taken into the body as food. From the standpoint of heat-producing capacity they more than double, weight for weight, meats and starches, and are, therefore, instinctively highly prized by dwellers in cold countries where much heat is necessary. In warmer countries the necessity for excessive heat-production in the body does not exist. While oily substances are certainly capable of adding to the cushion of fat commonly found beneath the skin in normal individuals, they are not looked upon as being to any extent tissue-builders, resembling in this particular the starches and sugars. When fats are to be eaten, care should be taken that they be as fresh as possible, or, if this is not feasible, they should be preserved in such a way as to prevent their becoming rancid--a condition which is the result of the formation of fatty acids, lending a peculiarly unpleasant odor and taste, and producing a decided decrease in food-value. This alteration may be largely prevented by keeping fats in a refrigerator at a low temperature, and may also be greatly retarded by the addition of salt. In this country butter is usually treated with a very considerable amount of salt, but in Europe it is universally served fresh. Within recent years facts have been established that show that Americans use an excessive amount of this substance--possibly causing disease in some cases; and doubtless we would be better off if we were to follow the European practice.