374 Messrs. F. Kidd, C. West, and G. E. Briggs. 



Hours 2 4 6 8 iO ;2 H 16 18 20 



compared with values calculated from the respiratory index determined 

 at 10° C. on one occasion during the eight days. For the purpose of this 

 calculation, the physiological mean temperature for each period was found 

 from the temperature record.* Our method of obtaining this is as follows. 



* There are several possible methods of obtaining the average temperature for a 

 period. The geometric mean temperature would be used in preference to the arithmetic 

 mean temperature, because the rate of a physiological process is not a linear function of 

 temperature. But since the temperature coefficient decreases with increase of tempera- 

 ture it is not sufficiently correct to use a geometric mean. 



