^^2 Journal of Comparative Neurology and Psychology. 



The paths taken throughout all the experiments by the 

 guinea pigs, their customary accuracy in turning corners, and 

 the general precision of their movements after the problem is 

 learned give unmistakable evidence of the great importance of 

 kinesthetic sensations in the recollection of the path. 



Test X. Preference for the dark. 



A series of experiments was now tried which did not lead 

 to anything definite, and hence will be only mentioned. 



Observation had not indicated any preference of the guinea 

 pigs for the dark side of the cages, or for remaining under cover 

 except when frightened, but the fact- that always in the ev^ening 

 they are most active suggested that there might be a preference 

 for dark passages. 



A large galvanized iron box was divided into a light and a 

 dark compartment, and an opening was so arranged that the 

 partition in the box divided it also into halves. Food was 

 placed in equal amounts at the distant ends of both compart- 

 ments, and the guinea pigs were placed outside in the experi- 

 mental cage. That tracking or any odor other than the food 

 might not complicate the situation, the box and cage were al- 

 ways carefully washed after each trial. 



The first few records with two of the four animals tried in- 

 dicated a slight preference for the dark side ; but all the rest of 

 the trials, forty or more, showed the choices of the light side 

 to be equal to those of the dark side.' 



The conclusion, therefore, was that for this particular kind 

 of test there was no preference for the dark. 



Green, blue and red glass covers were substituted first for 

 the white glass, and then for the black glass covering the re- 

 spective compartments, but in a large number of trials no pref- 

 erence was indicated. 



' Dr. Watsox found with the white rat no preference for dark passages. 

 Animal Education, p. 56. 



[40] 



