WILLIAM H. COLE 



571 



definite form the effect of temperature on the phototropic response of 

 Necturus, and it may be concluded that the decrease in the reaction 

 time is due to an increase in the velocities of the chemical processes 



V 



12' 



zv 



32°C. 



Temperature 



Fig. 1. Relation between temperature and reaction time. Each point is the 

 average of sixty trials; ten on each of six animals. Intensity of light, 4,200 

 candle meters. 



which cause muscular movements, and not to any effect of the tem- 

 perature upon the photochemical reaction. 



48 hours after the eyes had been removed, the six' animals were 

 tested again at each of the four temperatures, and with a light inten- 



