84 



Sl3cty-flve Day Rats. 



These rats began the problem when sixty-five days old, and 

 were fed in the maze for one week before actiaal experimentation 

 began. They were lively, but did not show the superabundant 

 activity of the twenty-five day group, and were not so speedy. 

 Twenty-seven rato were run, sixteen males and eleven females, 

 representing nine strains as follows: 



Trials variel from fourteen to sixty -five, absolute time from 

 four and seven tenths to eleven and eight tenths, total time 

 for sixty -four minutes to seven hundred thirty -one minutes; and 

 total distance from ninety-one and eight tenths meters to seven 

 hundred fifty meters. Here as in tlie preceding group, we can 

 trace no close connection between number of trials and time or 

 distance. The rat which finished in the fewest number of trials 

 had ft low time record and the lowest distance record for the 

 group, while the one requiring the greatest number of trials had 

 the highest time and distance records. So far the relation seems 

 very close. But the lowest time record was made by a rat fin- 

 ishing in twenty-tv.o trials, whose distance record was high, 

 while two other rats which finished at tventy-two trials had 

 very high time and distance records. The next to tlie highest 



