Role of Sight in Daily Life of Dancer 191 



was laid over the electric wires and therefore prevented the 

 punishment of mistakes. The purpose of these tests was to 

 discover whether the smoked paper, which was an essential 

 condition for the next test, was itself a disturbing condition. 

 These tests were continued until the animal had followed the 

 path correctly, despite the smoked paper, twice in succession. 



V. The electric lights were now turned out and tests were 

 given in total darkness, with smoked paper on the floor as a 

 means of obtaining a record of the number of errors. These 

 tests were continued until the path had been followed once 

 correctly. 



VI. The labyrinth was now thoroughly washed with warm 

 water, to which a little kerosene had been added, and quickly 

 dried over a steam radiator. This usually necessitated a 

 delay of about five minutes. As soon as the labyrinth was 

 dry, tests were given to discover whether the odors of the 

 various passages had been serving as important guiding 

 conditions. These tests were continued until the path had 

 been followed once without error. 



VII. A final test in darkness completed the series. 



As it was not possible for the observer to watch the ani- 

 mal and thus to count the number of mistakes which it made 

 in total darkness, the simple method of placing a piece of 

 smoked paper on the floor of the labyrinth was used. The 

 mouse left a graphic record of its path 'on the paper and 

 from this the number of errors could be ascertained. In 

 the tests now to be described the smoked paper was placed 

 upon the electric wires, but later a form of electric labyrinth 

 was devised in which it was underneath and therefore did 

 not interfere with the electric shock. 



The above series of tests was given under the same external 

 conditions in a dark-room to six pairs of dancers. In all 

 cases, two individuals, a male and a female, which had been 



