GROWTH OF THE CEREBRAL CORTEX ig [Ss 
TABLE 16 
Giving the computed number of nerve cells in the entire cerebral cortex of the Nor- 
way rat brain, obtained on the basis of the measurements given in this series of 
studies. These values are made to be comparable with the corresponding values 
of the computed number of nerve cells in the cortex of the albino rat brains of 
like brain weight groups 
NORWAY RATS ALBINO RATS 
A B Cc D E F G 
Sum of aD Computed ll : Corresponding 
mber of cells 
| Computed | Meello | entire. "| numberof |, omUeM 
Brain weight Brain weight artes in Jam. pyr. cortex,! cells in fetes ; e 
group FXW. p|_2ndJam. NXE. | the Nowray, |) apis of the 
TC | gang. in two xD xe to that = or 
GES unit cy + {in the Albino Sale Sroun, 
volumes, NV CX 100 pumabek 
grams mm 3 
N XI 1.163 281.00 181 508 .6 0.946 537.4 
N XII ; o20au 
N XIII 1.369 326.51 166 542.0 0.981 5P4 71 
N XIV 1.480 348 .09 160 548.9 1.009 544.0 
N XV oS 361.83 144 521.0 1.011 o15.3 
N XVI 1.629 382.32 138 527.6 1.020 517.4 
N XVII 1.739 402.47 132 doles 0.997 533.0 
N XVIII 1.829 423 .00 131 554.1 1.009 549.2 
N XIX 1.972 430.57 127 546.8 1.061 S15RS 
N XX 2.052 425 .59 123 92520 1.016 515.0 
N XXI PAS LP 475.66 MP SB VAaU/ 
Average (Groups N XIII-N XX)........ 536.9 TRO 530.2 
1 As remarked in a note to table 7, the number given in this column corre- 
sponds to 1/100 of N X L. F X W. D X T, or 1/50,000 of the actual number of 
cells contained in the computed volume of the cortex. 
the Norway by about 537 (the average of Groups N XIII- 
N XX) or about 1 per cent more than that of the Albino, which 
has been indicated by about 530 (the average of Groups XIII-— 
XX, see table 7), so that the number of nerve cells in the entire 
cortex of the mature Norway and of the Albino rats may be re- 
garded as practically the same, as suggested by Donaldson 
(Donaldson and Hatai, 711). 
