Before the physiologic effects of heat are discussed it would be instructive to consider the factors constituting the physiologic background for the regulation and maintenance of body temperature. This will afford a scientific basis for the dynamic stability of body temperature and indicate the modus operandi of the various factors taking part in regulation of temperature and in production of the physiologic effects.
NORMAL RANGE OF BODY TEMPERATURE
The temperature of the human body, in health, remains remarkably constant under conditions of extremely varying heat production and heat loss. The normal range of body temperature as determined by a thermometer placed in the mouth is between 96.7 and 99 F. The average is about 98.6 F. (37 C.). The rectal temperature is about 1 F. higher (97.2 to 99.5 F.) and the axillary about 1 F. lower than the oral temperature. Rectal temperature is the highest and most reliable. The