Nearly all people in normal health instinctively avoid heat-producing foods in hot weather, and as in warm or hot climates people live more in the open air, oxidation is therefore more perfect, and has a tendency to aid elimination, so the errors of diet are not so serious. Nevertheless, the food to be taken in hot climates, or the heated term of summer, should receive scientific consideration. Anthropoid life, of which man is the highest type, originated in the tropics, and nearly everything necessary for his highest physical development grew prodigally in that country. His natural or primitive diet was nuts, fruits, and salads (edible plants). Civilization has transplanted him in the north, and has laid heavier burdens upon him, therefore he needs, in many instances, heavier and different foods, such as the carbohydrates, proteids, fats, and the albumin and the phosphorus in eggs. As the temperature becomes warmer, the heat-producing factors, such as fats and carbohydrates (starch and sugar), should be gradually reduced. The following menus are suitable for the average person, in normal health, between the ages of thirty and sixty, when the temperature is ranging from 70° to 90° Fahrenheit: BREAKFAST Cantaloup, peaches, or berries Very ripe bananas, with grated nuts and cream A glass of milk LUNCHEON One whipped egg A fresh vegetable A teaspoonful of nuts A lettuce and tomato salad A baked sweet or white potato DINNER Peas, beans, asparagus, or corn A salad, with grated nuts and carrots A potato One whipped egg Half a glass of milk A service of gelatin These menus are mere suggestions, not invariable, and in following them it should be remembered that all green salads may be substituted for one another, and as a general rule such underground articles as beets, carrots, turnips, and parsnips may be substituted for one another. Also green corn, peas, and beans are in the same general class. (See "Constipation," Vol. III, p. 761.) Observation of these rules will give the student rather a wide range of articles to draw upon in selecting a diet for the normal person. LESSON XVII NERVOUSNESS ITS CAUSE AND CURE The nerves of the human body are the most important, the most complex, and probably the least understood of any part of the human anatomy. In conditions of health they are never heard from, therefore every expression of the nervous system is a symptom of some abnormal physical condition. [Sidenote: True meaning of nervousness]