GROWTH OF THE CEREBRAL CORTEX 251 
TABLE 4 
The thickness of the cerebral cortex of the pig, quoted from Bevan Lewis (779) 
Depth of cortex from before backward: 
mm. 
(4.97 
4.48 
3.70 
4.98 
3.58 
erik 
PAV CT AD Claw) Ae gel gine Demand A KEEN cov al. fi antece #4 6 areraloer se Reon eee tes 4.22 
(3.28 
2.65 
3.08 
3.91 
4.23 
3.44 
sia vCal O be yes. 3 re ee OTe ese tele ben, oe Eo eer 
Upper parietal convolutions.......... BA Seach AEN USE a et 
3.50 
3.44 
3.91 
3.95 
HAVEL ACR EST ke OTA, Aen Ee yo ota. cyory es ces 
Gowersparietaleconvolutlonsseer eee eer. oor nice eeenre 
JNA GTIE ZOE & & Rear diy BEw-0 PERIENCE Gee 5 BTS ER TG Os oe emer notte core a oc cole 3.64 
are analogous to those given for the rabbit brain, loe. cit.). His 
results are summarized in table 4. These values are distinctly 
high compared with those for other mammals, as shown in the 
various tables in this paper. These results taken together with 
those for the rabbit just given, which are also noticeably high, 
suggest that the determination by Lewis are for some reason 
systematically too high. 
Marsupials to man. Table 5 is quoted (slightly modified) 
from Brodmann (’09) and gives for several species of mammals, 
including man, the cortical thickness at six localities (areae 
precentralis, frontalis, parietalis, occipitalis, hippocampica et 
retrosplenialis) in the brain of each animal. The sections were 
made by hardening the material in 4 per cent formaldehyde, 
imbedding in paraffine, and staining by the modified Nissl’s 
method, and the cortical thickness was measured by the microme- 
ter directly on the slide. The average thickness was calculated 
by me for the four areas, excluding the areae hippocampica et 
retrosplenialis which are heterogeneous in cell lamination. 
