168 M. F. WASHBURN AND EDWINA ABBOTT 



Series 23. Saturated blue and Stoelting black paper. Black 

 opens. The rabbits had been unable to discriminate red from 

 Stoelting black paper, and the only rabbit so far tested with 

 blue and grey 7 and 15 had not learned to discriminate them. 

 The combination of Stoelting black paper and blue paper should 

 then be equivalent, if the black door opened, to the ordinary 

 red -grey combination, the red door opening. Ten tests a day, 

 on May 10 and 11, were given Abednego with the blue and black, 

 and he chose the black without hesitation in each of the twenty 

 tests. Whether the blue looked like grey to him or not, it is 

 probable that the red looked like black. 



Series 24. Blue and Hering grey number 15. Blue opens. 

 This was a series of twenty tests only, ten on May 12 and ten 

 on May 13. The blue door was pushed only 30 per cent, of the 

 time, seven out of the ten choices on each day being of the grey. 

 It is difficult to account for this sudden tendency to choose the 

 grey, which had not been once touched for a long period, except 

 on the supposition that the rabbit was continuing the habit of 

 choosing the darker impression, and that grey number 15 looked 

 darker to him than blue. One other possibility is that he was 

 avoiding the blue for some reason. But inasmuch as his previous 

 experience with blue had been confined to twenty tests with 

 blue and black, in none of which he had touched the blue, his 

 avoidance could not have been on the basis of experience gained 

 in the experiments. It might have been innate. And the 

 choices of the grey might, in view of the small number of experi- 

 ments, have been accidental. 



Series 25. Blue and Hering grey number 7. Blue opens. 

 This series lasted from May 1 5 to May 2 2 , a period which included 

 some abnormally hot weather, during which the rabbits were 

 languid and did not work well. There were 76 experiments in 

 all. The total percentage of correct choices was 48. The percent- 

 ages for each day, ten experiments being made on all the days 

 but one, were 40, 30, 70, 60, 60, t,^,, 50, 50. Unless this record 

 is due to the hot weather, the combination presented great 

 difficulties in the way of discrimination. , 



Series 26. Blue and Hering grey number 2. Blue opens. 

 This grey is next to the lightest in the Hering series, and to 

 human vision is almost white. The series lasted from May 23 

 to June 6. One hundred and fifty-four experiments were made 



