Tlie Sense of Sight : Brightness Vision in 



TABLE 12 

 POSITION OF WHITE CARDBOARDS FOR A SET OF 150 TESTS 



It is to be noted that in the case of each series of ten tests 

 the white cardboard was on the left five times and on the 

 right five times. Thus the establishment of a tendency in 

 favor of one side was avoided. The irregularity of the 

 changes in position rendered it impossible for the mouse to 

 depend upon position in its choice. It is an interesting fact 

 that the dancer quickly learns to choose correctly by posi- 

 tion if the cardboards are alternately on the left box and on 

 the right. 



The prevalent, although ill-founded, impression that mice 

 have an exceedingly keen sense of smell might lead a critic 

 of these experiments to claim that discrimination in all prob- 



