14 



S. I. FRANZ AND K. S. LASHLEY 



Experiment 13. G2cf. Sixty-nine days old. Learning was com- 

 pleted in 24 trials with 2 trials per day. Training was continued for 

 200 trials. 



Frontal lobes destroyed by a transverse incision. Retention was 

 tested twenty-two hours after the operation. The animal was very 

 weak and spastic. He had great difficulty in finding the food and 

 gnawed at the edge of the dish as much as at the bread. Nevertheless 

 he followed the direct path to the food with never a suggestion of reac- 

 tion to the entrance to the cul de sac. During the trials there were 

 many stuporous pauses (one of fifty seconds duration, which accounts 

 for the long time consumed in the fifteen trials recorded below) so, 

 after five trials the rat was returned to the home cage and the tests 

 continued two days later when he had recovered strength. The records 

 of learning and retention follow. 



Experiment 14- F4cf. Sixty-nine days old. Learning was com- 

 pleted in 18 trials with 2 trials per day. Training was continued for 

 120 trials. 



Frontal lobes destroyed by a transverse incision through a small 

 trephine hole on the left. Retention tested 20 hours after operation. 

 The animal had developed a left hemi-paresis and failed to leave the 

 starting compartment of the maze in an hour on each of three consecu- 

 tive days. Autopsy showed an extensive clot over the orbital sur- 

 face of the right hemisphere, extending back to the pons. 



