18 



GARDNER CHENEY BASSET 



TABLE lid 

 THE MAZE 

 ANATOMICAL DATA OF SIXTH AND SEVENTH GENERATION INBRED RATS 



. In Plate IV is shown the curve of learning (below) and of 

 relearning (above) of the 6th generation of inbred rats compared 

 with those of the 7th. These curves are constructed from figures 

 given in Table II. The curve of the 6th generation rats is indi- 

 cated by the broken line, that of the 7th generation by the solid 

 line. The ordinates show the average daily time in seconds for 

 each group, and the abscissae the number of the day in which 

 such time was made. From the twenty-second day the curve 

 of learning of the 6th generation lies below the six-second mark, 

 and from the eighty-third day is flat at 5.158 seconds, signi- 

 fying that on that day the last of this group had perfected the 

 habit. The 7th generation learning curve is very irregular 



