Finally, we may call attention to the many possibilities of an intelligent modification of the daily diet to the temporary needs of the individual. The season of the year, summer and winter, the climate, the degree of activity of the body, the state of health, temporary ailments, etc., all present special conditions which admit of particular dietetic treatment. In hot summer weather, for example, there is plainly less need for food than in the cold winter season, especially for fat with its high calorific value. During the cold part of the year, the lower temperature of the surrounding air, with the tendency toward greater muscular activity, calls for more extensive chemical decomposition in order to meet the demand for heat, and the energy of muscular contraction. There is perhaps no special reason for any material change in the amount of proteid food consumed in the two seasons, except in so far as it may seem desirable at times to take advantage of the well-known stimulating properties of proteid to whip up the general metabolism of the body, in harmony with the principle that all metabolic processes may need spurring to meet the demands of a greatly lowered temperature in the surrounding air. Fuel value, however, should be increased somewhat during the winter months in our climate. Fat promises the largest amount of energy, but there is more of a tendency to store up excess of fat than of carbohydrate, hence the latter foods have certain advantages as a source of the additional energy needed during cold weather. In warm weather, it should be our aim to diminish unnecessary heat production as much as possible, though it must be remembered that the body is to be maintained approximately at least in equilibrium, and this calls for an adequate amount of food. Lighter foods, however, may be advantageously employed, such as fruits, vegetables, fresh fish, etc. Fats and fat meats especially are to be avoided, not only because there is no specific need for them, but particularly on account of a greater sensitiveness of the gastro-intestinal tract during the hot seasons of the year, that is liable to result in a disturbance whenever undue quantity of rich or heavy food is taken. Further, in hot summer weather we may advantageously live more largely on foods served cold, and thereby avoid the heat ordinarily introduced into the body by hot fluids and solids. These, however, are all obvious physiological truths, constituting a form of physiological good sense the application of which calls for no special expert knowledge.