588 



METABOLISM 



the same amount of work as he performed before becoming fatigued, 

 will do so at a much greater expenditure of energy. 



There is a diurnal variation in the respiratory exchange, which is in 

 (general parallel with the body temperature; it rises during the day, the 

 (time of activity and work, and falls during the night, the time of rest 

 'and sleep. Foodjilso affects respiratory exchange, but it will be unnec- 

 essary to go into this further after what has been said on page 582. 



