BODY HEAT 53 



Even if one transposes day and night by a journey to 

 the other side of the world, the temperature rhythm 

 adjusts itself to the new conditions, so as still to show 

 the normal daily curve.* 



There is a considerable amount of evidence, also, to 

 show that the temperature of the body is not quite 

 uniform all over the globe, but that it tends to be 

 somewhat higher in the tropics than it is in temperate 

 regions. This is probably owing to interference with 

 heat loss. The central temperature, however, is much 

 less affected by climate than that of the periphery of the 

 body. 



TEMPERATUKE-REGULATING MECHANISM. 

 The constancy of temperature of the body is attained 



1. By varying the heat loss (physical regulation). 



2. By varying the heat production (chemical regu- 



lation). 



1. Physical Regulation, 



In man the heat loss is regulated (a) naturally, 

 (b) artificially (i.e., by clothes and artificial heating of 

 rooms). 



(a) The Natural Channels of Heat Loss are 



Percentage of 

 Total Heat Loss. 



(i.) The skin ... ... ... 87'5 



(ii.) The lungs ... ... ... 10'7 



(iii.) The excreta ... ... 1-8 



* Gibson, 'The Effects of Transposition of the Daily Eoutine 

 on the Ehythm of Temperature Variation' (Amer. Journ. Med. 

 Sci., 1905, cxxix., 1048). 



