GROWTH OF THE CEREBRAL CORTEX 245 
TABLE 1 
Giving for each locality of the brain of the adult mouse the characteristics of the 
cell lamination, the thickness of the cortex on the slide as determined from the 
photograms given by Isenschmid (’11), and the relative thickness of the outer and 
inner layers as presented by the same author. For the localities consult figure 1 
in this paper, which was reproduced from the original of Isenschmid (711) 
RELATIVE 
THICKNESS OF 
THE OUTER AND 
ees CHARACTERISTICS OF. THE AREA IN CELL-LAMINATION THICKNESS OF | INNER LAYERS 
(FIG. 1) THE CORTEX 
OF THE 
CORTEX 
OUTER: INNER? 
mm 
a) Largest ganglion cells contained (18 X 204)... 0.73 48: 52 
alam Notsomanrgencelll sen. 4.08. oiiccsa stern: cog ekewene 
Des lV alan erktlitekesnshe Sr cree sae ot ey roe ds eee cies 0.86 45: 55 
CER eRe leery «ry WAR ee ks aha deg, MR'e Tbe 8 0.50 45: 55 
CUM Ese ctsicrc hac tae Sete Chat a ee ACER ch af ¢ 0.53 45: 55 
Gin lmicansitionalqart pygon tases a hi aertriele cms alee as). 
hin ie aleopallaims 2: s 48 send cee seer ticks eect ad 2 
e IV layer not so well developed................ 42: 58 
f Adjoins to fovea limbica, cell lamination not 
CLES pb trea re. Meee eis hae 0.62 
THe 3] eked tienes aed Cee eC Aa at AAR MRM aie 8 UA OO og 0.44 
k Transitional part (ganglion cells: 13 & 15 n).. 0.81 34: 66 
] At the corner (ganglion cells: 12 X 14y)...... 0.78 P32 TC 
100: 4 nd Beco eR Meroe: Ok Satie blew kown co hikck Bese Drie ck ea ere aS 0.71-0.61 
Tema Pe ren eA ee EEN: cae satol esters Ph estde cvs hee 1.201 22:78 
q (Gangliontcellsissb) <8 jp) ners se res ett ha 2 0.56 28: 72 
s Similiar: GOraVe BaGlie chin ny ierte aye ycuatpe seine vee aches 0.26 
Be Aa RS 2 AMES Re (CEE Ae Rare Pe On WO) Se ee 0.34 
' Section cut obliquely. 
2 The outer layer = the lamina granularis externa plus the lamina pyra- 
midalis plus the lamina granularis interna. The inner layer = the lamina 
ganglionaris plus the lamina multiformis. 
of Isenschmid. Isenschmid (711) has recorded the thickness 
of the cerebral cortex of the mouse on the slide at every locality 
mapped in his figure (fig. 1). But the actual thickness not being 
given explicitly for each locality, I calculated the values from 
the direct measurements made on the photograms. The brain 
was fixed in alcohol, imbedded in paraffine and cut in 10-micra 
sections and stained with kresyl-violet. The thicknesses of the 
- cortex on the slide as thus obtained are given for each locality 
in table 1 and also are condensed in table 2, in which the data 
