266 The Dancing Mouse 



tests, and although they are not quantitative, I venture to 

 call attention to them. Indeed, I am led by the results of 

 my study of various aspects of the dancer's behavior to con- 

 clude that the race exhibits individual differences in discrim- 

 inating sensitiveness to a far greater extent than do most 

 mammals, not excepting man. The importance of this fact 

 (for I am confident that any one who carefully examines the 

 detailed results of the various experiments which are de- 

 scribed in this book will agree that it is an established fact) 

 cannot be overlooked. It alters our interpretation of the 

 results of training, memory, heredity, and discrimination 

 experiments, and it leads us to suspect that the dancing race 

 is exceedingly unstable. I do not venture to make compari- 

 son of my own observations of the dancer's sense equipment 

 with those of Cyon, Rawitz, Zoth, and Kishi, for the differences 

 are too great in many instances to be thought of as other than 

 species or variety peculiarities. It has seemed fairer to com- 

 pare only individuals of the same breed, or, as I have done 

 and shall continue to do throughout this chapter, of two lines 

 of descent. 



With respect to docility individual differences are prominent. 

 We need only turn to the various tables of results to discover 

 that in modifiability of behavior, in memory, in re-learning, 

 not to mention other aspects of docility, dancers of the same 

 sex and age differed strikingly. Let me by way of illustra- 

 tion cite a few cases of difference in docility. Number 1000 

 learned to discriminate white from black more quickly and 

 retained his habit longer than any other dancer with which 

 I have experimented. I should characterize him as an excep- 

 tionally docile individual. Table 44 offers several examples. 

 Numbers 403 and 407, though they were born in the same 

 litter and were alike in appearance and in conditions of life, 

 acquired the white-black habit with a difference in rapidity 



