SOME RACIAL PECULIARITIES OF THE NEGRO BRAIN. 
BY 
ROBERT BENNETT BEAN, 
Instructor in Anatomy, University of Michigan. 
From the Anatomical Laboratory of the Johns Hopkins University. 
WirH 16 Ficures, 12 CHARTS, AND 7 TABLES. 
From time to time in the past hundred years attempts have been made 
to determine the distinctive points of difference between the Caucasian 
and the Negro brain. While differences in skull capacity, in brain weight 
and size—especially of the frontal lobes—or in the gyri have been 
demonstrated by Gratiolet, Tiedemann, Broca, Manouvrier, Peacock, 
Marshall, Parker, and others,—more recently by Waldeyer in Germany 
and by Elliott Smith in Egypt,—yet no exact measurements of the brain, 
such as we have of the skull, are to be found.’ 
An effort will be made to show by measurement of outline drawings of 
brains in different positions, by composites of these outlines, and by 
actual drawings from individual brains that there is a difference in the 
size and shape of Caucasian and Negro brains, there being a depression 
of the anterior association center and a relative bulging of the posterior 
association center in the latter; that the genu of the corpus callosum 
is smaller in the Negro, both actually and in relation to the size of the 
splenium; and that the cross section area of the corpus callosum is 
greater in relation to brain weight in the Caucasian, while the brain 
weight of Negro brains is actually less. The amount of brain matter an- 
terior and posterior to the fissure of Rolando is roughly estimated, but 
other points of possible difference, as in the gyri, the insula, the opercula, 
the “ Affenspalte,” the proportions of white and gray matter, and the 
cerebro-cerebellar ratio are necessarily omitted in this study. 
In December, 1904, I reported to the Association of American Anato- 
mists the results of the measurements of fifty-four brains, thirty-seven 
from American Negroes, and seventeen from American Caucasians, Since 
1The brains measured for this work are in the Wistar Institute under the 
same numbers given in Table I. 
AMERICAN JOURNAL OF ANATOMY.—VOL. V. 
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