24 



both tine and distance become much more gradual, and continued 

 30 until the problem was learned. Tlie rat roferrei to above re- 

 quired on the fifteenth trial twenty -four seconds, and ran seven 

 and two-tenths meters, on the thirtieth trial the trip occupied 

 fourteen seconds and covered five and six-tenths meters. This 

 ] articular animal completed the problem at the sixty-sixth trial 

 when the time record was seventy and two-tenths seconds and the 

 distance record four and five-tenths meters, which, it will be 

 remembered, constitutes a perfect run. 



The data set forth above may be conveniently tabulated thus 



Distance run in maze be- 

 Trial Time required to reach fore reaching food. (The 

 food true pathv»ay 4.5 M. ) 



49.6 meters 



30.9 



10.2 



8.6 



7.2 



5.6 



4.5 



This rapid decrease in time and distance at the beginning 

 of the problem was characteristic ai all groups, and is clear- 

 ly shown in the initial drop in all the curves. 



The Twenty-five Day Rats . 



Work on this group began at twenty-five days when the 

 rats were so small that they could crawl through the mesh toi- 

 of the maze, and could touch the sides of the alleys only by 

 running from side to side, while other rats could remain in 

 the center of the path and touch both walls of the runways with 



