THROWING BACK 85 



always spin in the same direction, but sometimes 

 with the hands of the clock, and at other times in 

 the contrary direction. A " waltzing " mouse is not, 

 however, always spinning. It spins at night, as a 

 rule, and sleeps during the day when it is not 

 being fed. But it can always be recognised as a 

 " waltzer," even if it is not spinning, so long as it 

 is awake, by the following characteristics ; first, an 

 apparently complete lack of control over the move- 

 ments of its head, which is thrust up and down and 

 moved rapidly from side to side in a peculiar manner 

 which cannot be forgotten, but is not easily described ; 

 secondly, by a curious habit which it has, when 

 placed in a large open space, such as the floor, of 

 backing very vigorously as if it were on a slow- 

 moving avalanche, and moving its head, which is 

 kept near the floor, rapidly from side to side. Not 

 only can the adult " waltzer " be recognised as such 

 when it is not waltzing, but the young can also be 

 recognised before they can waltz, because they can 

 hardly keep on their four legs. The waltzer is 

 characterised by great delicacy and stupidity. The 

 death-rate is higher amongst them than amongst 

 ordinary tame mice ; they often fall out of the cage 

 when the door is opened, and are greatly inferior 

 to the albino, for instance, in the care of the brood. 

 They seem to be deafer than ordinary mice ; at any 

 rate, they take fright much less readily at a small 

 noise than an ordinary mouse does. For instance, 

 if a noise is made with the tongue and teeth whilst 

 a waltzer is at food, he will not, as the albino probably, 



