148 



The Dancing Mouse 



that they lack green-blue vision, or that they have it in a 

 relatively undeveloped state. 



If it be objected that the number of training tests given was 

 too small, and that the dancer probably would exhibit dis- 

 crimination if it were given 1000 instead of 200 tests in such 

 an experiment, I must reply that the behavior of the animal 

 in the tests is even more satisfactory evidence of its inability 

 to choose than are the results of Table 20. Had there been 

 the least indication of improvement as the result of 200 tests, 

 I should have continued the experiment ; as a matter of fact, 

 the mice each day hesitated more and more before choosing, 

 and fought against being driven toward the entrance to the ex- 

 periment box. That they were helpless was so evident that it 

 would have been manifestly cruel to continue the experiment. 



TABLE 21 



VIOLET-RED TESTS 

 With Odor of All Cardboards the Same 



