EXPERIMENTS ON THE RABBIT 159 



Series 2. Red and Hering grey number 7. This was the light- 

 est grey we used in connection with red. Red opens. This 

 series was performed under the same conditions as the preceding 

 one. The total number of experiments was 30. The total percentage 

 of correct choices made by Light Nose was 84. His percentages 

 calculated for the first three days was 62 ; for the second three 

 days, 95; for the third two days, 100. The series lasted from 

 January 4, 191 1, to January 12. 



Series 3. Red and Hering grey number 24 (a darker grey 

 than the others). The conditions were as before. The total 

 number of experiments was 73. Light Nose made a total percentage 

 of right choices equal to 65. His percentages calculated every 

 three days were 75, 50, 75, 75, 58, 46. His falling off at the end 

 was due to the fact that the presence of his mate was becoming 

 too much of a distraction to him. From this time on we were 

 obliged to separate them. The series lasted from January 13 

 to January 31, 1911. 



Series 4. Red and Stoelting black paper. Red opens. The 

 paper thus designated is that supplied in rolls as black paper 

 by the C. H. Stoelting Company. It varies somewhat in bright- 

 ness, but stands closer to Hering grey number 46 than to any 

 other of the Hering greys. Light Nose's mate was removed 

 from the hutch and yard during these experiments, and Light 

 Nose was tested alone in the yard. His four tests therefore 

 followed each other at a shorter interval than had previously 

 been the case ; and if his previous successes in choosing the red 

 door had been due to a habit of alternating from side to side, 

 this habit should now have had more favorable opportunity to 

 develop. There were 32 experiments in the series. The total 

 percentage of correct choices made by Light Nose was 37. The 

 reason why it dropped below 50 was that the rabbit quickly 

 formed the habit of going to the right-hand door in nearly every 

 test. We occasionally tried to break up this habit by putting 

 the red paper on the left-hand door in several successive tests, 

 instead of alternating it from side to side. Fourteen tests were 

 made with the red on the right, in eleven of which the rabbit 

 chose correctly; and eighteen with the red on the left, in which 

 he made only one correct choice. This formation of a place 

 association under conditions which should have strengthened 

 an alternating habit, had one existed, but which substituted a 



