EXPERIMENTS ON THE RABBIT 165 



grey number 1 5 looked darker to her than the blue : . at the same 

 time the number of experiments is too small to allow us to make 

 this statement with certainty. It is a disadvantage of the method 

 of interpolating tests that much time is required to gather a 

 few results. The series lasted from April 10 to April 16. 



Series 18. Stoelting black paper and grey number 7. Grey 

 opens. This series was undertaken with a view to training Dark 

 Nose to choose the lighter rather than the darker of the two 

 papers presented, in order that further color experiments might 

 be made with this reversed habit as a basis. We did not antici- 

 pate that it would take as long to form the habit of opening 

 the grey door as proved to be the case. The experiments were 

 made at the rate of ten a day. In all there were 387. The 

 daily percentages of right choices, that is, choices of the grey, 

 were 10, 10, 30, 40, 50, 50, 55, 41, 37, o, 40, 57, 50, 50, 55, 50, 

 30, 30, 50, 80, 60, 80, 100, go, 60, 80, 70, 60, 70, 70, 70, 70, 90, 

 90, 90, 60, 70. Evidently there existed to be overcome one of 

 two tendencies: either a strong tendency to choose the darker 

 of the two impressions presented, or a strong inhibition of the 

 impulse to push grey, whose absolute character was somehow 

 impressed on the rabbit's mind. The series lasted from April 17 

 to May 26. 



Series 19. Red and Stoelting black paper. Red opens. This 

 series was a final attempt to see whether the red-Stoelting 

 black discrimination could be acquired. Ten experiments were 

 made a day. The total number of experiments was 173, and the 

 total percentage of correct choices was 48. The daily percentages 

 were: 37, 77, 62, 50, 50, 40, 60, 40, 20, 55, 55, 33, 63, 45, 50, 

 50, 30. Twice in this series a well-marked right-hand tendency 

 appeared and once a left-hand tendency occurred for a short time. 

 Although the red-grey discrimination had been thoroughly 

 learned, and as Series 16 and 17 show could be rapidly re -learned, 

 no progress is shown in learning the red -black discrimination. 

 This series lasted from May 27 to June 12. 



C. Experiments with Abednego {male) 



The three rabbits born in the laboratory were first tested on 

 the twenty-fourth day of their lives. They were well able to 

 eat lettuce and carrots by this time, and much interested in 

 them. Their slowness in learning the box discrimination seemed 



