12 



S. I. FRANZ AND K. S. LASHLEY 



tenth and thirteenth trials she again entered the cul de sac but did not 

 go to the end. On the other trials she followed the most direct path 

 and cut close around the end of the partition. The records of learning 

 and retention were the following. 



Experiment 9. Dl 9 . Sixty-nine days old. Learning was completed 

 in 48 trials with 10 trials per day. Training was continued for 200 

 trials. 9 



The frontal lobes were destroyed by a transverse incision. Re- 

 tention was tested twenty-four hours after the operation. The rat 

 oriented correctly in the starting compartment, attempting to lift the 

 door by thrusting her nose under it. Two errors were made on the 

 fifth trial. The others were run correctly and by the shortest possible 

 path. There was no exploratory sniffing. The records of learning 

 and retention follow. 



Experiment 10. Blcf. Sixty-seven days old. Learning was com- 

 pleted in 70 trials with 10 trials per day. Training was continued for 

 200 trials. 



The frontal lobes were destroyed by a transverse incision. Re- 

 tention was tested twenty-eight hours after operation. On the first 

 trial the rat explored the maze hurriedly without pausing to sniff. 

 In the later trials he usually paused and swayed back and forth at the 

 end of the first passage but entered the cul de sac only once, on the 



