HEAT 



305 



tionary rate of loss, 21.7 Cal./kg. hr., prevails. This represents an 

 increase (augmentation ratio) of about 22 times the control rate 

 of heat loss. 



The resistance to heat loss might be computed in arbitrary 

 ways ; in any case it changes during the loading. By a usual defi- 

 nition the resistance is the reciprocal of rate of loss per unit tem- 

 perature difference between inside and outside. Lefevre (p. 498) 

 used as '^ coefficient of resistance" the ratio of heat production to 

 heat loss, but this is the definition of the economy quotient (§13). 



TABLE 34 



Bates of heat loss during loading, Cal./lcg. hr., in various species; indicating how 

 quicMy deficits of heat may be imposed. Data of Lefevre {1897) 



Negative heat loads of other types are produced by rectal irriga- 

 tion, or by drinking ice-water, or by surrounding the body with ice. 

 All are like baths in eliciting local deficits of heat that are later 

 distributed. 



Positive heat loads are rapidly acquired in physical exercise, 

 diathermy, intense radiation, stoppage of heat losses, and other 

 circumstances. 



For accurate measurement of the heat load, not only the total 

 heat lost but also the total heat produced during transition is ascer- 

 tained, for in any transitional state the load is the difference be- 

 tween the integrated gain and the integrated loss. Alternatively, 

 heat load is ascertained as the product of increment in tissue tem- 

 perature and of heat capacity. In the whole man, various tem- 

 peratures appear in diverse portions of the body, and approxima- 

 tions of their distribution (Burton, '35) are necessary to evaluate 

 the heat content of the body. This measurement is less practical 



