434 HALBERT L. DUNN 
cent in the fifth month and to 9.2 per cent in the tenth month. 
Or, in other words, the transverse axis of the cerebral hemispheres 
shows a constant diminution in the rate of growth throughout 
the fetal period. 
TABLE 17 
Volume of the cerebellum 
Formula: Volume of cerebellum (cc.) = .01 (.095 crown-heel length 
(em.))49 + 20.0 
(114 cases) 
hte Seals mic ted o  eanMRaLeM ii CALCULATED potecaane 
VOLUME OF | OBSERVED AND epee 
Maxi. Mini- CEREBELLUM | CALCULATED 
Range Mean arin aaa Mean MEANS 
cm. cm cc ce. cc cc cc 
Oto 5 
5 to 10 
10 to 15 12.8 0.5 0.1 0.3 0.5 +0.2 10 
15 to 20 16.9 0.7 0.2 0.4 0.5 +0.1 14 
20 to 25 22.6 2.0 0.5 0.9 0.6 —0.3 18 
25 to 30 27.0 Piste 0.9 1.3 12 —0.1 13 
30 to 35 aPAsTI 4.0 HO; 2.4 2.8 +0.4 16 
35 to 40 37.2 9.3 3.4 5.4 Nal —0.3 Nef 
40 to 45 42.3 15 N76 8.9 9.3 +0.4 11 
45 to 50 48.0 22.0 14.0 19.0 ilvfeal —2.0 7 
50 to 55 aoe 26.0 18.0 Dilisres PANU +4.4 8 
TABLE 18 
Calculated cerebellum volume at 5-cm. intervals of crown-heel length 
INCREMENT IN EACH 
CROWN-HEEL LENGTH | CEREBELLUM VOLUME 5-CM. INTERVAL 
RATIO TO NEW-BORN 
cm. ce. ce. per cent per cent 
5 
10 0.20 1.0 
15 0.28 0.08 40.0 1.3 
20 0.43 0.15 53.6 2.1 
25 0.89 0.46 107.0 4.3 
30 1.89 1.00 112.0 9.1 
35 3.80 io 100.1 18.2 
40 7.13 3.39 87.8 34.1 
45 12.60 5.47 76.8 60.3 
50 20.90 8.30 65.8 100.0 
50 33.40 12.50 59.8 160.0 
