INTRODUCTION 



Conditions for Experimentation. — In this study, experiments 

 with the porcupines, from May 26th to October 20th, were 

 carried on in an open-wire cage 8 feet by 20 feet and 7 feet 

 high, situated on a gentle eastern slope under the trees at the 

 experiment station connected with Clark University. On Octo- 

 ber 2ist transfer was made to winter-quarters where work was 

 continued until December 23rd of the same year. After that 

 an intermission of 100 days occurred for the purpose of testing 

 memory without intervening work. Various new check experi- 

 ments were instituted when work was resumed in the spring. 

 Winter-quarters consisted of a large, well-lighted inside room, 

 with a ground floor, provided with dark dens in close approxi- 

 mation of those in the wild. There was also an outside run 

 9 feet square and 7 feet high. Adjoining the inside apartment 

 were other rooms of a similar kind, where special apparatus 

 could be used and where the animals could be isolated during 

 experimentation. No artificial heat was used for obvious rea- 

 sons. From May 26th to September 25th, experiments were 

 made in the forenoon daily with a few short interruptions. 

 After that it was found to be more convenient to do work in 

 the afternoon. There was no difficulty, however, in changing 

 the time of day or the place of experiment, though both changes 

 were made with seven animals. Davis (14), it will be remem- 

 bered, lost ten weeks time in changing his raccoons from outside 

 cages to finished rooms and artificial heat. This difference in 

 the behavior of the raccoons and the porcupines in respect to 

 environment is very marked and the explanation is not cer- 

 tain. It may be that the porcupines are less sensitive to en- 

 vironment, which fact in turn, may be only a condition of 

 acuteness of sense organs. It is also possible that porcupines 

 can adapt themselves to a new situation more readily. And 

 again, it may be that the artificial heat and the closer confine- 

 ment of the raccoons lowered their physical vitality for a time. 

 Still other equally obvious explanations might be offered. 



The selection of this particular animal was made on the 

 recommendation of Dr. James P. Porter, Dean of Clark College. 



