EXPERIMENTS ON THE RABBIT 153 



exceptions she was tested every day. Work with the male 

 lasted until March 12, 1911, at which time we sent him away: 

 he was tested, or at least the attempt was made to test him, 

 every day with the exception of the interval during the Christmas 

 holidays. On January 22 a litter of three males was born (Shad- 

 rach, Meshach, and Abednego). Tests on these were begun 

 when they were 24 days old, and were continued with Shadrach 

 and Abednego during the greater part of the time until June 1 2 , 

 191 1. The entire family was disposed of at this date in June. 

 The next fall we obtained from the same dealer a young female 

 (Polly) whose exact age and antecedents were also unknown, 

 and experimented with her from October 3 until December 21, 

 191 t. With the exception of the illness of Dark Nose, above 

 mentioned, all the rabbits remained on the whole in excellent 

 health and spirits during the whole period of work. 



As was to be expected, the individual characteristics of the 

 six rabbits differed considerably. Light Nose, the father of the 

 litter was nervous, quick at learning, but decidedly unstable in 

 temperament. After making a perfect record on one day, he 

 would on the next day pay little attention to the box, but frisk 

 about or push the wrong door apparently from a mere vagrant 

 impulse. Dark Nose, the mother, was more stolid and more 

 steady: it was long before she succeeded in making a perfect 

 record, but when a discrimination was once acquired, she main- 

 tained a continuous high level of accuracy which her mate 

 never acquired. She showed less tendency than any of the other 

 rabbits to be distracted from the problem in hand, and in work- 

 ing on the difficult discriminations, while she would shake her 

 ears over a mistake, she showed no tendency to delay subsequent 

 trials because of previous failures, but worked with mechanical 

 regularity throughout. The maturing of the sexual instinct 

 in the male put an end to satisfactory work with him. If he 

 was allowed to be in the hutch with his mate at the time of the 

 tests his interest in her overcame his interest in food, and when 

 he was separated from her he was often too restless and ill- 

 tempered to test. For this reason, and because we did not have 

 time to test five rabbits thoroughly each day, we discontinued 

 work with Light Nose in the spring. 



Of the three young rabbits, Abednego was most thoroughly 

 tested. He was docile and steady. Shadrach was the most 



