AUDITORY SENSITIVITY OF THE WHITE RAT 



347 



TABLE ^Continued 



CONDITION OP TKST 



NUMBER OP 

 TRIALS 



NUMBER 

 CORRECT 



f Light 10 



J Handclaps 10 



Light 10 



[ Handclaps 10 



Normal handclaps 10 



Sandpaper 10 



Handclaps 10 



Sandpaper 10 



Sandpaper -. . . . 10 



Sandpaper 10 



. Handclaps 10 



Sandpaper 10 



Handclaps 30 



Light 10 



Handclaps 10 



Light 10 



Handclaps 10 



Light 10 



8 



8 



6 



8 



8 



5 



8 



8 



6 



6 



8 



5 



24 



10 



10 



9 



9 



10 



silence; run left for buzzer and right for silence; or run right for 

 h.c. and left for buzzer. Each day's work was begun with either 

 of the auditory stimuli. This determined the right or left turn 

 and silence was then treated accordingly. Controls were now 

 instituted in an attempt to determine just wherein the difference 

 between the two noises lay. Illness in the animals finally pre- 

 vented an entirely satisfactory solution. The data are presented 

 in their present fragmentary form because it will probably rarely 

 happen that an experimenter will have rats possessed of these 

 two habits, thus making possible the extension of the work. 



The work on auditory sensitivity in the white rat has indicated 

 an insensitivity to tones in the lower portion of the scale and also 

 to some as high as the pitch 4096 d.v. on the fork. It has also 

 demonstrated that the rat can hear noises. In the case of rats 

 7 and 27, the opportunity was offered to extend these previous 

 observations on noise. Are noises for the rat grouped into the 

 three classes of continuous, intermittent and beat noises as Hensen 

 claims for man? The buzzer used in the tests with rats 7 and 27 

 gave a continuous sound and the handclaps constituted an inter- 



