Characteristics, Origin, and History 15 



of behavior to develop by means of careful and patient selec- 

 tional breeding a race of mice which is remarkable for its 

 dancing. Even if it should be proved that the mutation as 

 it appears among common mice is not inherited, the view 

 that slight deviations were taken advantage of by the breeders 

 would still be tenable. The dancing tendency is such in 

 nature as to unfit an individual for the usual conditions of 

 mouse existence, hence, in all probability human care alone 

 could have produced and preserved the race of dancers. 



In answer to the question, how and when did the race of 

 dancers originate, it may be said that historical research 

 indicates that a structural variation or mutation which occa- 

 sionally appears in Mus musculus, and causes those peculiari- 

 ties of movement which are known as dancing, has been 

 preserved and accentuated through selectional breeding by the 

 Chinese and Japanese, until finally a distinct race of mice 

 which breeds true to the dance character has been established. 

 The age of the race is not definitely known, but it is supposed 

 to have existed for several centuries. 



