CEREBRAL FUNCTION IN THE RAT 



125 



tion of the records of the first two hundred trials (table 5) shows, 

 however, that he at first made some improvement both in time 

 and in the number of errors and that this improvement was per- 

 manent. This is evidence for learning, though of a simple type. 

 In the later part of training he developed a stereotyped reaction 

 to the maze which must be classed as a habit, though it did not 

 contribute to the getting of food. In the trials, day after day, 

 he would first turn into the entrance of the right alley, advance 

 for twice his body-length, then whirl about quickly, run to the 



TABLE 5 



Rate of learning in rat described in experiment 89 

 To right 



end of the left alley, turn back to the right alley and go directly 

 to the food. Records of time and errors for the first two hun- 

 dred trials are given in table 5. 



The rat was killed 71 days after the operation. Microscopical 

 examination of the brain showed (plates I and II, fig. 39) : 



Right hemisphere. There is a destruction of tissue over the 

 dorsal convexity of the cortex down to and including the corpus 

 callosum. There is transverse lesion extending diagonally for- 

 ward just behind the knee of the corpus callosum to the base of 

 the olfactory bulb, completely cutting off the frontal pole. The 

 for nix and gyrus dentatus are completely destroyed. The cor- 



