348 



REGULATION OF TEMPERATURE 



trate the influence of the rate of cooling on the body temperature 

 after severe work : 



TABLE LIX. 

 SOLDIERS ON COMPLETING A MARCH OF SEVEN MILES. 



On the cold day with a percentage difference of about 15 

 between dry and wet bulb temperatures, i.e. under good cooling 

 conditions, the temperature and heart rate of the soldiers showed 

 only a slight increase, while on the hot day with almost the same 

 humidity, the men became uncomfortably hot, and the heart rate 

 was increased. Under these conditions work is inefficiently done. 



The effect of the temperature and the humidity of the external 

 air on the loss of heat from the body is very well marked in those 

 people endowed with a good layer of adipose tissue. As has 

 already been mentioned, this dense non-conducting material is a 

 very effective heat insulator, thus preventing rapid heat loss. 

 In hot weather and during exercise, fat subjects become unduly 

 heated. If, in addition, they have poorly functioning sweat 

 glands, then severe or prolonged work becomes impossible. 



The following table gives a rough indication of the amount of 

 heat lost per day through the various channels : 



TABLE LX. 



The question now under consideration is, provided some 2500 

 calories of heat are lost per day, (a) how is excessive heat loss 

 prevented and (b) how is the amount lost made good ? 



