OS 
(9 2) 
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Some Racial Peculiarities of the Negro Brain 
superior end of the fissure, and on the 45° plane to the middle part of 
the fissure, and lines were drawn from the brain center to the inferior 
surface of the occipital and frontal lobes, striking them tangentially. 
These lines are taken as limits of the outlines, because no lines are shown 
in the drawings. The radius to the sulcus centralis is taken as the 
dividing line between the anterior and posterior parts of each outline. 
The temporal lobe is not included in the drawings. The area of each 
hemisphere, in three planes, both anterior and posterior to the sulcus 
centralis is determined by means of the planimeter. The results are 
found in Table V. These results are averaged, the averages for the an- 
terior part of each outline being added to one another, the same being 
done for the posterior part, and the sums placed together for comparison 
matable V2: 
The anterior part of the Negro brain outline is the same size as the an- 
terior part of the Caucasian brain on the left side; the anterior part of the 
Caucasian brain is larger than the anterior part of the Negro brain on 
the right side; while the posterior part of the Negro brain is larger than 
the posterior part of the Caucasian brain on each side. In the right 
hemisphere the racial distinction is considerable; in the left it is not so 
great. The similarity of the two races in the apparent size of the frontal 
lobes on the left side may be due to the greater size of the left motor area 
and of the left gyrus frontalis inferior in the male negro, as heretofore 
pointed out. The areas of the female Caucasian brain need not be con- 
sidered, because only three are given. The areas of the female Negro 
brains are less than the areas of the males in either race and the racial 
distinctions are relatively the same as in the male Negro. The distinc- 
tions throughout may be expressed in ratios of the anterior to the pos- 
terior parts of the brain representing the posterior part by 100 in each 
case (Table V°). 
TABLE Vb. 
RATIO OF THE ANTERIOR TO THE POSTERIOR PARTS OF THE BRAIN. 
Left Side. Right Side. 
Caucasianwmalemarceeeeeecoeeeeoee in. 104 : 100 106 : 100 
INGerotmalers oi.stesiee ces lelsternce 2 ano. 101 : 100 . 100+ : 100 
Caucasianstemalein renee ee eee oe 101 : 100 103 : 100 
Neerojfemaler 5 x.yosevacerete cictsicie ders « 102 : 100 101 : 100 
This table brings into clearer view the differences mentioned above. 
The frontal lobe of the male Caucasian is relatively larger than that of 
the Negro, and the right frontal lobe is both relatively and absolutely 
larger than the left. The right frontal lobe of the female Negro is rela- 
