118 Metabolism of Healthy Man. 



variations in body-temperature during pathological conditions, and hence the 

 discussion must be confined to normal individuals. 



Factors Influencing Body-Temperature. 



The body-temperature is a resultant of thermogenesis, or the development 

 of heat inside the body, and thermolysis, the dissipation of heat from the body. 

 Ordinarily these are so well balanced that the resultant temperature remains 

 reasonably constant. If, for any reason, there is a decrease in the radiation 

 or dissipation of heat, unless there is a compensating decrease in the generation 

 of heat, the body-temperature will rise. Conversely if there is a sudden increase 

 in the radiation of heat and no corresponding increase in the generation of 

 heat, there will be a fall in body-temperature. It can be seen, therefore, 

 that an elaborate study of body-temperature involves the study and, so far as 

 possible, the control of two rather fugitive factors, namely, thermogenesis and 

 thermolysis. Any extraneous or internal influences affecting either of these 

 factors will cause a disturbance of body-temperature. The marvelous thing 

 about it is that the two processes are ordinarily so delicately balanced. 



Topographical Variations in Body-Temperature. 



It is now known that heat is produced not in any one locality in the body 

 but throughout the whole organism as the result of the oxidation of tissues by 

 oxygen carried to the different parts of the body in the blood; thus, there is 

 an enormous source of heat production and a large surface for heat radiation. 

 The temperature of the body is not, however, by any means the same in all 

 parts, for we find the highest temperature in the interior of the body, deep in 

 the rectum, the extremities present a lower temperature, and the surface of the 

 skin obviously a still lower temperature. Using round figures, it may be said 

 that the internal temperature of the body is approximately 37 C. (98.6 F.), 

 and that the temperature of the skin is on the average about 32 C. (89.6 F.), 

 a difference of 5 C. (9 F.). Between the temperature at the warmest point 

 inside the body and the temperature of the skin there may be a gradient, and 

 hence the average temperature of the whole human body is a difficult thing to 

 determine. 



It has often been felt by the investigators in this laboratory that one of the 

 most important researches as yet lacking is a topographical study of body- 

 temperature and particularly a study of the fluctuations in different parts of 

 the body. A number of investigators have attempted this, usually by means 

 of clinical thermometers, and occasionally by means of thermo-electric junc- 

 tions, but we know of no study where the internal temperature was examined 

 more carefully and more continuously than in an investigation made by one 

 of us. 1 In the experiments referred to, an electrical-resistance thermometer 



1 Benedict and Snell, Pfliiger's Archiv f. d. ges. Physiol., 1901, 88, p. 492; ibid., 

 1902, 90, p. 33. 



