VISION IN THE MOUSE 



579 



MOUSE 



Ke 



Kh 



Ka 



J 



Q 



T 



X 



BF 



I" 



Xa 



Xc 



X.l 



Xc 



DATE OF EXPERIMENT 



white 



white 

 white 

 white 

 white 

 graj' 

 black 

 black 

 black 

 gray and white 1 

 gray 

 black 

 white 



male 



female 



male 



male 



male 



male 



female 



female 



male 



male 



male 



female 



female 



6 weeks 

 6 weeks 

 6 weeks 

 adult 

 adult 

 3 months 

 •'! months 

 3 months 

 5 weeks 

 2 months 

 2 months 

 2 months 

 2 months 



1906 

 1906 

 1906 



March, 1900 

 March.. 1906 

 March. 

 March, 

 March. 

 Oct. 10 

 Oct. 15 

 Oct, 15-17 

 Oct. 20-25, 

 Feb. 25-Mar. 23, 

 Feb. 25-Mar. 23, 

 Fed. 25-Mar. 23. 

 Feb. 25-Mar. 23, 



1906 



1907 

 1907 



1907 

 1907 



1 The gray and white mouse had pigmented eyes. 



The animals were tried separately. After each trial the posi- 

 tions of the partitions B and C were reversed. The reaction was 

 recorded as an error of choice, and therefore indicative of lack of 

 perception of depth, if the mouse inclined to the left when B was 

 the nearer to A", or to the right when C was the nearer. 



As a rule the mistakes were very marked. Often an animal 

 would run forward until its nose touched the partition. Again an 

 individual would slowly approach the partitions, examine them at 

 close range, and then dash through between them. Such reactions 

 as this last were of doubtful value in connection with the problem. 



Results: The following tables give the results for different 

 groups of mice and different positions of the partitions. 



Albino mice. Partitions respectively 10 cm. and 15 cm. from X. Reversed after 

 each trial 



