124 R. S. LASHLEY AND S. I. FRANZ 



vessels. The right half of the fornix is severed and there is an 

 extensive clot filling the third ventricle. 



There was in this animal a destruction of fully half the cortical 

 tissue, including the frontal pole and nearly all of the dorsal con- 

 vexity and embracing all of the excitable area and the area described 

 as motor by the histologists ; degeneration of the right corpus striatum 

 and fornix ; permanent spasticity confined to the left side] no loss of 

 learning ability beyond that due to motor incoordination. 



Experiment 39. Transverse frontal and longitudinal incisions 

 were made in the cortex of a small male rat, 126 days old. He 

 was very weak after the operation and grew emaciated rapidly. 

 A hemiparesis appeared immediately after the operation, giving 

 him some difficulty in walking and making it impossible for him 

 to sit up on his hind feet. In the home cage or in the maze 

 when his nose came in contact with the food he at once swung 

 his head to the left, away from the food and against the side of 

 the food dish, which he then gnawed. In order to eat without 

 constant help he had to be placed in a large dish of food. He 

 then usually twisted his head around to the left until his nose 

 was under his left hind leg and ate in that position, gradually 

 straightening out if left to himself. This behavior persisted 

 until the animal was killed, twelve weeks after the operation. 

 During the first three weeks after the operation he had an almost 

 constant erection of the penis and masturbated at frequent 

 intervals. There was a gradual recovery from this but a seem- 

 ing deterioration in other respects as he became more and more 

 inactive and stuporous. 



He was trained to go to the right in the simple maze 11 

 days after the operation. His paresis made it easier for him to 

 turn to the left and he showed little improvement in accuracy 

 after two hundred trials. The passage-way to the left was then 

 blocked and he was given one hundred trials with only the direct 

 way to the food open. He soon ceased to pause at the blocked 

 entry and ran directly to the food, but when the left passage was 

 again opened he at once entered it and did no better than before. 

 In all, four hundred and fifty trials were given but he only 

 once made five successive trials without error. An examina- 



