PHOTIC REACTIONS OF TADPOLES 



265 



reaction-times was subtracted 0.7 second, an assumed value 

 for the probable duration of secondary processes. The general 

 course of the curves in figure 7 is the same as that shown in 

 figure 6, and it is characterized by the same deviation in the 

 higher intensities. If, now, the values obtained with 60, 200, 

 and 500 candle-meters are also plotted, the region in the curves 

 representing these intensities assumes an irregular form. Other, 



TABLE 5 



Reaction-times in seconds of blinded Rana clamitans tadpoles to light intensities of 

 60, 200, and 600 candle-meters. Source of light above 



smaller, assumed values were subtracted from the average of the 

 reaction-times and curves for these values were also plotted. 

 They were 0.2 second and 0.5 second. Such a treatment of 

 the data led to no improvement in the reciprocal curves. With 

 an assumed value of 0.5 second for secondary processes there 

 was a slight improvement in the intensity-time products. But 

 here also the gradual characteristic deviation with the higher 

 illuminations was retained. This becomes clearer from an 

 inspection of table 6. The deviation with the higher intensities 



