420 
HALBERT L. DUNN 
The absolute volume of the entire brain when based on crown- 
heel length (fig. 3) is about 3.5 cc. at 10 em. (C H). 
This in- 
creases to 38 ec. at 25 em. (C H) and then more rapidly to 330 ce. 
at 50 em. (C H). 
Encephalon volume 
TABLE 3 
Formula: Encephalon volume (ce.) = (0.125 crown-heel length em.)*16 + 1.5 
CROWN-HEEL LENGTH 
(144 cases) 
OBSERVED VOLUME 
OF ENCEPHALON 
Range Mean 
cm. cm. 
Oto 5 3.9 
5 to 10 (POP 
10 to 15 ES 
15 to 20 16.9 
20 to 25 Pass 
25 to 30 20 1 
30 to 35 32.2 
35 to 40 37.2 
40 to 45 42.8 
45 to 50 48.0 
50 to 55 52.2 
Ne 
Neeey 
TE ARANORMOS § 
mM CO WAT ORO ON 
FON OnNNOO 
DONWNOO De 
ie 
oOrPN 
TABLE 4 
- CALCULATED 
VOLUME OF 
ENCEPHALON 
DIFFERENCE 
BETWEEN 
OBSERVED AND 
CALCULATED 
MEANS 
cc. 
NUMBER 
OF CASES 
Calculated volume of encephalon at 5-cm. intervals of crown-heel length 
CROWN-HEEL LENGTH 
VOLUME OF THE 
ENCEPHALON 
cc. 
3.0 
8.4 
19.6 
38.1 
66.6 
107.6 
163.3 
236.1 
328.9 
444.0 
INCREMENT IN BACH 5-cM. 
INTERVAL OF 
CROWN-HEEL LENGTH 
cm. 
per cent 
140.0 
133.5 
94.4 
74.8 
61.5 
51.8 
44.5 
09.4 
30.0 
RATIO TO NEW-BORN 
per cent 
