ONE of the mysteries of the human race is the fact that civalized man is subject to certain diseases that rarely attack primitive man and never appear in wild and domestic animals. These are various nervous and mental disorders, exophthalmic goiter, neurocirculatory asthenia, Raynauds disease, diabetes, peptic ulcer, essential hypertension, and coronary disease. Each of these diseases is related to the expenditure of energy. It would appear that this fact alone offers a biological clue to the mechanism of the energy characteristics of man and animals. It is well known that only certain organs and tissues control the expenditure of energy in all animals, including man. These are the brain, the heart and the blood, the thyroid gland, the adrenal glands, the celiac ganglia, and the sympathetic system. I postulated that if we were to analyze, measure, and compare the organs of this energy-controlling system in fish, reptiles, birds and mammals and then compare the influence of the heat of...