Characteristics, Origin, and History 13 



two original types appear among the offspring in the 

 carving. 



Experimental studies of the inheritance of the tendency to 

 dance are of interest in their bearing upon the question of 

 origin. Such studies have been made by Haacke (19), von 

 Guaita (17, 18), and Darbishire (13, 14, 15, 16), and the 

 important results of their investigations have been well sum- 

 marized by Bateson (5). 



By crossing dancing mice with common white mice both 

 Haacke and von Guaita obtained gray or black mice which 

 are very similar to the wild house mouse in general appear- 

 ance and behavior. The characteristic movements of the 

 dancers do not appear. As the result of a long series of 

 breeding experiments, Darbishire (16 pp. 26, 27) says : "When 

 the race of waltzing mice is crossed with albino mice which 

 do not waltz, the waltzing habit disappears in the resulting 

 young, so that waltzing is completely recessive in Mendel's 

 sense; the eye-color of the hybrids is always dark; the 

 coat- color is variable, generally a mixture of wild-gray 

 and white, the character of the coat being distinctly corre- 

 lated with characters transmitted both by the albino and 

 by the colored parent." When hybrids produced by the cross 

 described by Darbishire are paired, they produce dancers in 

 the proportion of about one to five. 



Bateson (5 p. 93, footnote), in discussing the results ob- 

 tained by Haacke, von Guaita, and Darbishire, writes: "As 

 regards the waltzing character, von Guaita' s experiments 

 agree with Darbishire's in showing that it was always reces- 

 sive to the normal. No individual in Fj [thus the first hybrid 

 generation is designated] or in families produced by crossing 

 F! with the pure normal, waltzed. In Darbishire's experi- 

 ments F x x F x [first hybrids mated] gave 8 waltzers in 37 off- 

 spring, indicating i in 4 as the probable average. From von 



