256 NAOKI SUGITA 
of the cortex at each is graphically presented in chart 2. Gen- 
erally summarized, the average thicknes of the cortex of the adult 
man is 2.92 mm.; females have a slightly thinner cortex than 
males (differences less than 1 per cent, or 0.02 mm.) and the 
right hemisphere usually has a cortex a few per cent less thick 
than the left (maximum difference 7 per cent). 
With the foregoing determinations are to be compared the 
measurements by three other observers. 
mm 
376425 101 131211 8 9 14 
Chart 2. -The curve was plotted according to table 8 to show the cortical 
thickness at each locality as measured by Donaldson (’91. |. The numbers placed 
by the ordinates indicate the thickness of the cortex in millimeters. The num- 
bers for the localities are given below, and correspond to those in figure 3, A. 
B and C. 
In accordance with this plan, the results obtained in a careful 
study by Hammarberg (’95) are tabulated in table 8. The 
material used for this study was a brain of a male, twenty-eight 
years old, mentally normal, and who died of typhoid fever. 
The technique employed was fixation in 95 per cent alcohol, 
imbedding in paraffine by means of xylol, sections 10 micra in 
