568 



NAOKI SUGITA 



Chart 7 Giving the corrected thickness of the cerebral cortex of the albino 

 rat in horizontal section. Individual entries for the cortical thickness at locali- 

 ties IX and XIII, and also the average thickness of the cortex of the horizontal 

 section at localities IX, X, XI, XII and XIII combined. Based on table 8. O, 

 Cortical thickness at locality IX. Corrected. X, Cortical thickness at locality 

 XIII. Corrected. •, Average thickness of the cortex of the horizontal section. 

 Corrected. 



By making tables 6, 7 and 8 in the form here used and by en- 

 tering for each brain weight group the data for the correction- 

 coefficient, it is made possible for any one who so wishes to re- 

 cover from the corrected values here given the values as obtained 

 by direct observation on the shde (table 5), though, in some in- 

 stances, small discrepancies result between the values thus cal- 

 culated and the values given in table 5, owing to repeated aver- 

 aging and the frequent dropping of fractions under 0.005 mm. 



To obtain the average thickness in any brain weight group the 

 values for the average thickness in sagittal, frontal and hori- 

 zontal sections are again averaged, as shown in table 9. The 



