za 



IS 



/.6 



I 



D 



O 



6 



0.7 



Q4- 0.5 



R.ec/procal of lo^I 

 Fig. 2. Relation between the reaction time and the reciprocal of the logarithm 

 of the intensity. Same experiment as Fig. 1. 



I 



o^ 



as 



09 



as ay aa 



/iec/procal of /ogl 

 Fig. 3. Relation between the reaction time and the reciprocal of the logarithm 

 of the intensity. Open circles are the data of Experiment 9.9; 250 watt lamp; 

 seven animals; one measurement for each animal for every intensity. Dark 

 circles are the data of Experiment 10.10; 100 watt lamp; seven animals; three 

 readings for each animal for every intensity. 



372 



