130 [ounial of Comparative Neurology and PsycJiology. 



TABLE III. 



Reaction-time to Electric Stimulation Alone, and to the Same when 

 Preceded for o.i, 0.5 or i.o Second by Visual Stimulus. 



In Table IV I have given the probable errors, standard 

 deviations and coefficients of variation of the means, except in 

 case of Series II. 



4. Electric Stimulation and Moving Red Disc. 



The indications of the importance of the temporal relations 

 of stimuli, so far as reaction-time results are concerned, fur- 

 nished by these crude preliminary observations led me to un- 

 dertake a more accurate study of the subject. To this end a 

 revolving disc, which moved at the rate of one revolution per 



