VISION IN THE MOUSE 



5 / o 



the column to pass through, was placed over the papers in order 

 that the surfaces might not be soiled-by the animals, as well as to 

 keep the papers flat and in position. A circular disk of polished 

 steel, 7 cm. in diameter, was fitted closely around the column over 

 the glass. This was intended to prevent the animals from jumping 

 down too close to the column. A small wooden disk wrapped with 

 electric wires was fastened to the top of the disk to bring about 

 a quicker reaction by making too long a stay on the disk slightly 

 unpleasant for the mouse. The wires from this small disk passed 

 through the larger disk and were sunk into the sides of the column, 

 thence they passed downward through the bench top to the floor 

 where they were connected with an induction coil and dry cell. 

 The time records are of little importance here, for the purpose 

 of the experiment was merely to observe the choice of the black 

 or white surface as a landing place. It was assumed that the ani- 

 mal would jump down on the surface which appeared to it the 

 nearer. 



Results 



Height of disk \ cm. above bench 



STIMULI'S 



Disk turned 180 degrees 



