212 THE HUMAN SPECIES 



in which they live, but that of the warm-blooded animals (like 

 man, homoiothermic) remains constant within very strict limits. 

 This means that some mechanism exists whereby heat-produc- 

 tion and heat-loss proceed simultaneously and exactly balance 

 one another. 



TABLE OF AVERAGE TEMPERATURES. 



Horse (in stable) . . . 37 - 96 C. 



(in the open) . . 3 7 -40 C. 



Ass ... 36-95 C. 



Ox . 38-2-39-3 C. 



Sheep . 37'3-40'5 C. 



Goat ..... 39-2-40-0 C. 



Dog . . . 37'5-39'5 C. 



Cat 38-3-38-9 C. 



Rabbit . . 37-5-39-5 C. 



Porpoise .... 38-5-39-4 C. 



Man (adult) .... 37-2-37-5 C. 



True vocal cords False vocal 



Epiglottis cords 



FIG. no. Larynx in inspiration. FIG. in. Larynx during phonation. 



(Munk-6chultz.) (Munk-Schultz.) 



The heat-production of a man aged twenty to twenty-one 

 years and weighing 60 kilogrammes amounts to 2,210 calories 

 per diem. 



The variations in the body temperature of man and 

 mammals, at different times of day or night, depends on the 

 food taken and the muscular activity. According to Munk l 

 the daily fluctuations in man are as follows : 



Early morning .... 36'8 C. 

 Forenoon . . . . . 37" i C. 



1 Munk-Schultz, loc. cit., p. 318. 



