122 K. S. LASHLEY AND S. I. FRANZ 



Experiment 38. Transverse frontal and longitudinal incisions 

 were made in the cerebral cortex of an old male rat, through 

 a circular trephine hole 8 mm. in diameter. After the operation 

 he was very weak and emaciated rapidly. He was fed by hand 

 for five days, then recovered the ability to eat alone. From 

 the day after the operation he showed a pronounced spasticity 

 of the left side, carrying his head rotated about 60 degrees to 

 the right and walking with the left hind leg extended stiffly 

 and only the tips of the toes set down on the ground. During 

 the first few days he fell over at every third or fourth step and 

 always made a complete rotation to the right in getting to his 

 feet again, his behavior resembling that of an animal after uni- 

 lateral destruction of the semicircular canals. 



In the cage the animal was much more restless than any of 

 the others in the group. He ran almost constantly around an 

 oval path, bounded by the sides of the cage, and always in the 

 same direction, clock-wise. On one day, 35 days after the 

 operation, his activity was observed nearly continuously for 

 12 hours. During this time he ran around the same path 

 at an average rate of twenty devolutions per minute, with a 

 total of not more than one hour's interruption for rest and eat- 

 ing; a total distance of not less than seven miles. During the 

 40 days that he was kept under observation he showed very 

 little improvement in motor control beyond that acquired in 

 the first week after operation. 



Habit formation. Training in the simple maze was begun 12 

 days after the operation. He was active, although his move- 

 ments were very badly coordinated. On the first trial in the 

 maze each day he had great difficulty in walking and his first 

 passage of the central alley was usually a series of somer- 

 saults. After the first trial coordination was usually better. 

 After sixty to seventy trials in the maze he learned to tra- 

 verse it with a few falls but this was accomplished by support- 

 ing himself against the sides of the alleys and not by improve- 

 ment in walking in a straight line. He always had great diffi- 

 culty in turning around to his left and when he finally learned 

 to go to the food in the left alley of the maze he accomplished 



