352 C. H. TURNER. 



direction along the right path. From the time the roach entered 

 a blind alley until it returned to the right path was counted one 

 error. If a roach which was moving in the wrong direction along 

 the right path paused from time to time, each movement after a 

 pause was counted an error. Movements, other than dashes 

 into the water, which were made by a roach on / before it had 

 entered the runway I were not counted; but once the roach had 

 entered the runway i, even though it returned to the starting 

 platform /, all incorrect movements made by it were counted 

 errors. 



In my first experiments I arranged for the successive trials of 

 each roach to come at intervals of several hours. This was done 

 because I had an idea that experiments conducted at short 

 intervals would produce fatigue effects which would vitiate the 

 work. However, I soon found that the best results were obtained 

 where the successive trials came at intervals of about half an 

 hour and were continued throughout the working hours of a day. 

 Towards the end of a long hot day such fatigue effects as a 

 pronounced slowness of movement and the lapsing into errors 

 that the roach had formed the habit of omitting would appear; 

 but, on the whole, the repetition of trials at short intervals was 

 much more satisfactory than the other method of experimenting' 



DISCUSSION OF THE EXPERIMENTS. 



Upon being placed on the maze for the first time, a roach 

 almost invariably rushes off into the water. Upon being re- 

 placed on the maze, it usually repeats the performance; some, 

 however, do not rush into the water a second time. Sooner or 

 later it stops rushing into the water and begins to move around 

 in search of some other means of escape. It moves to and fro 

 along the runways, if paths with neither sides nor top may be 

 called runways, enters blind alleys, occasionally falls into the 

 water, 1 makes its toilet one or more times, perhaps engages in a 

 few acrobatic stunts, and finally, by accident, discovers the 

 incline and passes down it to the glass cell that is its home. The 

 first time the roach is placed on the stage, this performance 



1 After it had fallen into the water, the roach was always replaced on the maze at 

 the place from which it had its fall. 



