GROWTH OF CEREBRAL CORTEX 3 
TABLE 2 
Giving the brain weight for each brain weight group, the cube root of the brain weight 
and the linear measurements for width, length and height of the cerebrum. Nor- 
way rat. W. B = Width AB; W. D = Width CD, L. G = Length EG, L. F= 
- Length EF (see figure 1). Ht. = Height HK (see figure 2) 
BRAIN CUBE ROOT 
WEIGHT Sarees ee, pea W.B W.D AG: Bs 0 Ht. 
CAROWIE WEIGHT 
grams mm. mm. mm. mm. mm. 
N XI 9 1.161 1.051 13.86 12.69 12.63 L218 8.83 
N XII 0 
N XIII 2 1.356 IP LO7 14.20 12.98 13.60 13.05 9.45 
N XIV 2 1.4386 1.128 14.45 11336741 1) 7A 13.24 9.31 
N XV 5 1.536 1.154 14.7 seo 14.18 13.48 9.28 
N XVI 8 1.644 1.180 14.91 13.65 14.24 13.62 9.61 
N XVII 8 1.743 1.204 15.10 13.92 14.54 13.88 9.97 
N XVIII 4 1.836 1225 15.17 14.20 15.00 14.32 9.98 
N XIX 3. 1.965 22 15.68 14.28 15223 14.68 10.08 
N XX 5 2.033 1267 oO 14.34 1 5e52 14.74 10.02 
N XXI 4 2.164 1.293 16.25.) 14.94 15.92 155112 10.18 
N XXII 1 2.266 1.314 16.60 14.90 16.15 15.70 10.35 
N XXIII 1 2.345 1.329 16.55 15.65 16.30 15.50 10.25 
of the albino rat and denoted by the same abbreviations (figs. 
1 and 2). The data are arranged in groups according to the 
increasing values of the brain weight at intervals of 0.1 gram. 
Chart 1 gives a graphic view of the average measurements of 
the Norway cerebrum in each brain weight group, plotted on the 
basis of the data in table 2. 
A study of the individual records used for table 2 shows that 
within any group the individual variability does not amount to 
more than +1.2 per cent, as compared with the average values 
for the group and each diameter shows a relatively steady in- 
crease, generally in close relation with brain weight. 
On examining Chart 1, the curves for W. B and W. D are 
found to run almost parallel and the same is true for the curves 
L. Gand L. F, as seen already in the case of the Albino cerebrum. 
By a comparison of the graphs for the width with the graphs for 
the length, it is evident that the rapidity of growth along the 
sagittal diameter is greater than that along the frontal diameter, 
a relation that was also seen in the Albino cerebrum. AH. in- 
creases slowly as compared with the other diameters. 
