CEEEBKAL FUNCTION IN LEAENING 61 



ity given by them. Without careful training experiments such 

 observations, are absolutely worthless. My own experience 

 with an animal of the present series illustrates this. The rat 

 (number 19, section III) had extensive destruction in the frontal 

 and parietal regions. She had a paresis of the right legs which 

 made her walk stumbling and uncertain, disturbance of the 

 musculature of the face and excessive length of teeth which 

 gave her an expression of extreme stupidity. She seemed to 

 wander about aimlessly, rarely reacting to stimuli which 

 influenced normal animals. Several people who saw her 

 remarked her stupidity and predicted that she would never 

 learn the problem and this was also my impression. Yet the 

 animal learned the difficult double-platform box in 27 trials, 

 which is less than one fifth of the average of normal animals, 

 and showed in overtraining tests a constancy of performance 

 rarely equalled by normals. 



But few attempts have been made to train animals after 

 complete destruction of the cerebrum. The observations of 

 Goltz ('92) upon his decerebrate dog extended over a period of 

 more than eighteen months and some efforts were made to train 

 the animal (to back out of a narrow stall) but the author feared 

 to continue training because of the danger of producing con- 

 vulsions and death by continued stimulation. The result of 

 the tests were negative, but Goltz admits that the training was 

 not continued long enough to justify the conclusion that the 

 animal could not learn. Aside from the rapid recovery of 

 walking coordinations which was probably a concomitant of 

 recovery from shock, he reports no improvement except that 

 of finding food. The swallowing reflex could not be elicited 

 at first except by placing food in the pharynx. Gradually 

 the reflex came to be called out by more distal stimuli to the 

 tongue, chewing movements appeared, and on the twenty-fourth 

 day after the operation food was first taken when placed against 

 the lips. A similar improvement was reported by Rothmann 

 ('12) who did not give the time for recovery. Rothmann further 

 reported that his dog learned to accommodate the stepping 

 movements of his hind legs to follow the movements of a chair 



