78 K. S. LASHLEY AND S. I. FRANZ 



The brains were first turned over to a technician to be sec- 

 tioned. As a result two brains were lost and several others so 

 badly prepared that accurate reconstructions were impossible. 

 Six brains were sectioned by the technician, the remainder by 

 one of the writers. In the descriptions of the lesions reference 

 is made to well defined land-marks, particularly the limits of the 

 ventricles, the divisions of the corpus callosum, the gyrus hip- 

 pocampus, and the subcortical ganglia. The relative positions 

 of these structures are shown in the serial sections, figured in 

 plate I, figure 22. 



I. THE RETENTION OF A SIMPLE KINESTHETIC-MOTOR HABIT 



AFTER DESTRUCTION OF THE FRONTAL POLE OF 



THE CORTEX 



In experiments described earlier (1) a number of animals were 

 trained in the simple maze (fig. 1). An attempt was then 



FIG. 1. THE SIMPLE MAZE 

 a, starting compartment; b, middle alley; c, cul de sac; d, alley leading to food. 



made to destroy the frontal portion of the cortex by transverse 

 incisions through small openings in the parietal bones and as 

 soon as the animals had recovered sufficiently from the opera- 

 tion, usually within forty-eight hours, they were tested for 

 retention of the habit. In thirteen of the fourteen animals 

 that survived the operation there was demonstrated some re ten- 



