570 



NAOKI SUGITA 



This table 9 is valuable as a standard for the discussion of the 

 actual growth of the cortex in thickness according to brain 

 growth (weight), because these values have been corrected to 

 the fresh condition and may be regarded as giving a truthful 

 picture of the thickness of the cerebral cortex of the albino rat 

 from birth to maturity. 



TABLE 9 

 Showing the average (corrected) thickjiess of the cerebral cortex in the al'jino rat by 



brain weight groups 



The average thickness of the cerebral cortex of the adult albino 

 rat is 1.88 mm., as obtained by averaging the values for the 

 Groups XI to XX, in which stages the cortex may be considered 

 as having reached about its full thickness. 



The following chart 9 is based on table 9. This chart is very 

 interesting and important for the further consideration as a 

 standard picture of the cortical development and to it I shall 

 refer in tbe following chapter. 



