MILAN 



minute intervals. The factor 0.86 was used to convert watts to 

 kcal/hr (Handbook of Chemistry and Physics). 



The subject reclined in the bath with all except his face im- 

 mersed in water. The subject's total heat loss was determined with 

 a correction applied equal to the caloric equivalent of the water 

 displaced by the subject. Total immersion time was one hour. Al- 

 though heat production did not equal heat loss during this hour and 

 true steady state conditions were not achieved, rates of change were 

 constant during the last 30 minutes, and these data were used. This 

 period is what Burton (1939) has termed a "dynamic steady state." 



Heat production . Heat production was continuously monitored by 

 the respirometer-oxygen analyzer combination utilized to measure 

 basal metabolic rates. 



Rectal temperature . An indwelling catheter type thermistor was 

 inserted 10 cm into the rectum and secured to the buttock by water- 

 proof tape. Temperature^ were measured on a Yellow Springs 

 Instrument Go. Telethermometer and recorded on the strip chart 

 of an Esterline Angus Recorder. 



Calculation. The Laws of Heat Transfer by Thermal Conduction 

 have been summarized by Hardy (1949) and are analogous to Ohm's 

 Law for electrical circuits. The fundamental equation for heat con- 

 duction in the steady state is: 



H = KA(T - T ) X t, gm cal 



where: 



Hp. = quantity of heat conducted 



K = thermal conductivity, a constant 



A = area of conducting surfaces 

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