620 



TABLE III. 

 Intensity of the omnilateral fore-illumination 25 C. M. 



Duration of 

 omnilateral fore- 



Energy of the unilateral after-illumination in C. M. S. 



illumination 



22 



44 60 ' 120 500 1000 4500 13.500 27.000 



10 sec. 



36 sec. 



100 sec. 



3 min. 



5 min. 

 20 min. 



1 hour. 



+ 

 ++ 



TABLE IV. 

 Intensity of the omnilateral fore-illumination 100 C. M. 



Duration of 

 omnilateral fore- 



Energy of the unilateral after-illumination in C. M. S. 



illumination 22 44 , 60 120 500 1000 4500 13.500 27.000 



10 sec, 

 36 sec. 

 100 sec. 

 5 min. 

 20 min. 

 1 hour. 



+? 

 + 



_? 



++ 



these intensities of foie-illumination the sensitiveness to the positive 

 reaction diminishes at first. Whereas at 12.1 C. M. (table II) it was 

 always possible to obtain a positive effect, this is not so at stronger 

 intensities. At 25 C. M. and 100 C. M. (tables III and IV) it is no 

 longer possible to bring about a positive curvature after a fore- 

 illumination of 100 seconds. 



Just as in table I the possibility of obtaining negative curvatures 

 disappears with increased duration of the preliminary exposure, we 

 see also from tables II, III, and IV, after a certain period of fore- 



