GROWTH OF THE FETAL CENTRAL NERVOUS SYSTEM 463 
Cerebral growth. The growth of the cerebrum is characterized 
by a steady absolute increment in all of its lmear measurements 
from the second fetal month until birth. This can be observed 
by the inspection of the curves of the fronto-occipital length and 
the temporal diameter (fig. 29, curves I and II, respectively). 
4 = 3), "oP et al Pes Geel le T i T — | 
cm. ; ‘ ‘ , 
O coe | eines | eee 
O 5 {0 15 £O Eby 830 IDO) 45 50° 55cm. 
Fig. 24 Field graph and curve of the growth of the spinal cord and brain stem 
in fetal life as shown by the brain-cord length. Abscissa: total body length in 
em. Ordinate: brain-cord length in em. Individual cases indicated by solid 
dots. Curve drawn to the formula: Y = (10.0X)-*!4 —4.0. (Data from tables 
38 and 39.) 
These curves are both straight lines and lie intermediate to the 
vermis cerebelli absolute curves below and to the curve of the 
spinal cord above. When calculated against time in fetal months 
(fig. 33, curves I and II), the fronto-occipital length and the 
(Text continued on page 479) 
