74 The Dancing Mouse 



to believe that the mice are deaf, and this despite the fact 

 that he observed no responses to the sounds made by a series 

 of tuning forks ranging from C 5 to C 8 . He believes rather 

 that they are strangely irresponsive to sounds and that their 

 sensitiveness is dulled, possibly, by the presence of plugs of 

 wax in the ears. Since another investigator, Kishi, has 

 observed the presence of similar plugs of wax in the ears 

 of common mice which could hear, there is but slight 

 probability that Panse is right in considering the plugs 

 of wax as the cause of the dancer's irresponsiveness to 

 sounds. 



Far more thoroughgoing tests than those of Rawitz or 

 Panse were made by Cyon (9 p. 218), who holds the unique 

 position of being the only person on record who has observed 

 the adult dancer give definite reactions to sounds. To a 

 Konig Galton whistle so adjusted that it gave a tone of 

 about 7000 complete vibrations per second, which is said to be 

 about the pitch of the voice of the dancer, some of the ani- 

 mals tested by Cyon responded unmistakably, others not at 

 all. In one group of four mice, two not only reacted markedly 

 to the sound of the whistle but apparently listened intently, 

 for as soon as the whistle was blown they ran to the side of 

 the cage and pressed their noses against the walls as if 

 attempting to approach the source of the stimulus. The 

 remaining two mice gave not the slightest indication that 

 the sound acted as a stimulus. By the repetition of this 

 sound from eight to twelve times Cyon states that he was 

 able to arouse the mice from sleep. When thus disturbed, 

 the female came out of the nest box before the male. Simi- 

 larly when the mice were disturbed by the whistle in the 

 midst of their dancing, the female was first to retreat into 

 the nest box. There is thus, according to Cyon, some indi- 

 cation of sex, as well as individual, differences in sensitiveness 



