Ill 



OF TEMPERATURE COEFFICIENTS 



231 



Temperature-coefficients (Q^q) of Drosophila 



And Japanese students, studying a little fresh- water crustacean, have 

 carried the experiment much beyond the range of Van't Hoff 's law, 

 and have found length of hfe to rise rapidly to a maximum at about 

 13-14° C, and to fall slowly, in a skew curve, thereafter* (Fig. 67). 



20 30 40 



Temperature, °C. 

 Fig. 67. Length of life, at various temperatures, in a water-flea. 



If we now summarise the various temperature-coefficients (Q^) 

 which we have happened to consider, we are struck by their 

 remarkably close agreement: 



Yeast Qi = M3 



* A. Terao and T. Tabaka, Duration of life in a water-flea, Moina sp.; Joum. 

 Imp. Fisheries Inst., Tokyo, xxv, No. 3, March 1930. 



