GROWTH OF THE CEREBRAL CORTEX 207 
TABLE 9—Continued 
a cORT. CORT. z 
cS AREA | AREA eo 
eo) ager (OR eae eg CORT CORT A 
Berg ee ANP | con-| & | prain| 2: F | varcxn. | RATI0|W.D| varckn. |RATIO| 7 
TROL | = |wrIGHT EN LN Ba 
3 SAGITTAL FRONTAL Ee, 
7 SECTION SECTION S y 
oJ 
daus grams mm, mm. mm. mm. 
Series II 
F a, b T. I |138—| 0.832)11.18) 13.2 1.19)11.23 9.9 0.88} 101 
c-l T. [1/25+] 1.204)12.66) 14.4 1.14)/12.30) 10.9 0.88) 97 
Series III 
B a-g T. I |11+] 0.844)10.99; 13.0 L TSiiie22\ Oe? 0.90) 102 
h-] T. I1j22—| 1.154)12.58) 14.3 L. T41027-20) 10 N4 0.87| 97 
Average T. I |11—| 0.758/10.45| 12.6 1.21)10.81 9.7 0.90) 104 
(Ser. I-III) T. IT/20—| 1.107|12.27| 14.1 PHILO ORG 0.87) 99 
Average } C. I | 8—|.0.700) 9.88} 12.3 1.24/10.63 9.6 0.88) 108 
(Ser. I) C. I)19+] 1.226)12.63} 15.0 LSLO 270 eile 0.88) 101 
of more than sixteen days, so that after this period there is no 
longer any significant difference in the cortical volumes between 
the test and the standard animals. 
10. NUMBER OF NERVE CELLS IN THE CEREBRAL CORTEX 
The actual number of nerve cells in the frontal cortex in a 
unit volume of 0.001 mm.’, or 0.1 mm.? in area on the slide by 
10 micra in thickness, was counted in the lamina pyramidalis and 
in the lamina ganglionaris at locality VII, the middle part of the 
cortical band of the frontal section. The procedure for counting 
the cell number, adopted by me for the standard values and 
described in my previous paper (Sugita, ’18 b), has been strictly 
followed here also. The number of cells in the lamina pyramidalis 
and the lamina ganglionaris and the number of the ganglion cells 
in a unit volume have been recorded and then converted into the 
number of cells in the same unit volume in the fresh condition 
of the brain by the use of the correction-coefficients based on 
observations. All the data have been tabulated in table 10a 
(unpublished) and condensed in table 10 for each group. The 
