298 ALDA GRACE BARBER 



correctly, with the possible exception of the fact that he was 

 consequently delayed a moment or two in being fed. As the 

 rat was allowed only a nibble of the bread held over the side 

 of the box, his zest for the work was not impaired during the 

 8 trials given per day. The records were noted in symbols, 

 e. g. « A' tq B' C D 16-14. Interpreted, this means that 



the rat was standing in the inner triangle, A' (see fig. 1), headed 

 away from the experimenter (^ ) when the signal was given, 

 turned quickly (tq), went through triangles B', C, D, standing 

 up finally at section 16 in D, while the experimenter Was at 



section 14. 



The accuracy of localization is therefore 2. A regular series 

 of presentations was used, in which each of the 32 sections of 

 the box (see fig. 1) was given once every four days while each 

 side of the box was given once every day. The order was 

 as follows: 



14 3 11 31 24 5 25 20 



The capitals stand for the different sides of the box, and the 

 numbers for the sections. Daily records were tabulated from 

 the reactions of each rat by averaging the eight trials. The 

 results are in terms of error, i. e., of accuracy of localization, 

 denoting how many sections the rat missed the point of tapping. 

 The reaction of the rat was considered completed when he 

 stood up, and no further record was made for that test, regard- 

 less of subsequent behavior. 



After the rat had been trained to a degree of accuracy which 

 was reasonably constant from day to day, whereby the fact 

 was established that the animal was localizing something, the 

 next phase of the problem was considered, viz., was the reaction 

 an auditory one. To establish this point controls were put in 



