It is generally taught that man is a homothermal organism, that he has a wide range of adaptability to external atmospheric conditions, that his mean daily temperature varies between 98 and 99 F., this being subject to minor variations according to age, exercise, altered respiration, period of the day, food metabolism, etc. Some observers, nevertheless, have shown that there is a certain relationship between the body and atmospheric temperatures. Hermans1 records that in crowded theaters and churches his own body temperature rose. Castelli and Chalmers2 observe that if a person, lightly clad and in good health, places himself in the hottest part of an engine room on a steamer in the Red Sea, it will be found that for a short time his temperature remains normal, but in due course of time his temperature will gradually rise to 102 F. or over, when the person breaks off the