TEMPERATURE OF THE BODY.
The production and regulation of heat in the body is a problem by no means elucidated. We consider heat production to be of internal origin, by a complex process involving tissue metamorphosis, chemical changes in nutrient elements, muscular movements, etc. Heat regulation is accomplished, not only by variation in the loss of heat by the body, but by what is more important, variations in the amount of heat generated. It is an accepted physiological conclusion that there exists in the body a thermotaxic nervous mechanism which controls its normal, as well as its abnormal, manifestations of heat.
The average temperature of the body in health is 37° C. (98.6° F.), in the axilla. Taken in the vagina or rectum, .9° C. (1.3° F.) higher is noted. The daily average range of variation is about 1° C. (1.8° F.).
In disease or injury considerable variations occur; very high, as well as very low, temperatures are met. In severe neuroses and some forms of malarial disease a temperature of 42.2° C. (115° F.) has been recorded, and after an injury 71° C. (122° F.).[688]
Very low temperatures are reported in several cases of acute alcoholism, accompanied by exposure to cold, where a temperature of 28.8° C. (75° F.) in the rectum was noted, recovery following.[689]
Such extreme temperatures, though authentic, are exceptional.
Very high temperatures in febrile conditions are borne because remitting; and low temperatures, subject to periods of elevation, are met in wasting and other conditions. Very high and very low temperatures are also noted, just before death, in acute diseases and conditions specially involving the nervous system.
The degree to which the temperature may be raised without destroying life has been investigated by Berger, Bernard, Chossat, and others.[690]
Their experiments show that if an elevation of temperature of the body 7.20° C. (13° F.) be maintained for any length of time in warm-blooded animals, death ensues. Depression of the temperature of warm-blooded animals 12° C. (20° F.), or even less than these degrees below the normal, results fatally. Portions of the body may be frozen and yet, under appropriate treatment, recover. But freezing of the whole body must necessarily prove fatal.
Great differences in ability to endure extremes of heat and cold appear among different nations and in different individuals. The very young and the very old are unable to bear exposure to extreme cold. In both, the capacity for heat production is low and the vital powers are soon enfeebled to a critical degree. The healthy adult can, with proper precautions, safely endure great extremes of heat and cold. The experience of arctic explorers in the expeditions of Kane, Nares, Greely, and others has demonstrated the power of endurance, for a considerable period, of a temperature from 90° to 100° F. below the freezing-point. On the other hand, laborers employed in pottery and other establishments, using ovens raised to 148° to 315° C. (300° to 600° F.) or higher, are often exposed for some time without injury to temperatures approaching these intense figures.