GROWTH OF THE FETAL CENTRAL NERVOUS SYSTEM 
When calculated to age in fetal months (fig. 34, curve I), the 
volume of the entire brain is about 1 cc. at the beginning of the 
third month. It increases to 14 ce. by the first of the fifth month, 
and reaches the value of 330 cc. by birth. 
The rate of growth of the encephalon when determined by 
5-em. percentage increment (fig. 26, curve II) is approximately 
Calculated weight of the encephalon (based on collected data) at 5-cm. intervals of 
CROWN-HEEL LENGTH 
CROW N-HEEL LENGTH 
Range 
cm, 
Oxtoms 
5 to 10 
10 to 15 
15 to 20 
20 to 25 
25 to 30 
30 to 35 
35 to 40 
40 to 45 
45 to 50 
50 to 55 
TABLE 5 
crown-heel length 
Tae re | eee ae | saara ne manor 
grams grams per cent per cent 
3.3 0.8 
9.4 6.1 185.0 yal 
PPA AL PAT 135.0 5.6 
44.0 21.9 97.5 1 4 
77.8 33.8 76.8 19.8 
126.6 48.8 62.7 Bye 
193.3 66.7 52.7 49.1 
281.0 87.7 45 .4 71.4 
392.9 111.9 42.4 100.0 
pyAai 139.2 35.4 163565) 
TABLE 6 
Volume of the encephalon (data of Jackson, ’09) 
(31 cases) 
ENCEPHALON VOLUME 
Mean Maximum Minimum Mean 
cm. cc. cc. cc. 
1.8 0.4 0.25 0.18 
Ue! 3.6 2.0 2.83 
ee 20.0 10.0 1340 
WZ 40.0 18.0 22 
22, A 60.0 30.6 45.9 
27.4 129.0 HZ ea 85.4 
S208 126.7 120.0 123.3% 
38.5 140.0 140.0 140.0 
44.2 BPA A es) 321.3 
45.9 358 .0 278 .2 322.6 
51.9 385 .0 363 .0 374.0 
NUMBER 
OF CASES 
NONrRre NW Or OW W & 
