386 Some Racial Pecuharities of the Negro Brain 
In dealing with the corpus callosum as a whole, it is found to be smaller 
in the Negro than in the Caucasian, just as the brain of the Negro is 
smaller than that of the Caucasian, and in about the same degree. The 
averages of brain weights and areas of the corpora callosa reveal interest- 
ing racial and sexual differences. ‘They are given in Table I?, with 
ratios made up from Table I. 
TABLE Ia. 
Tur RELATION OF THE AREA OF THE CORPUS CALLOSUM TO BRAIN WEIGHT- 
AVERAGES AND RATIOS. 
iets Goren Galleeaee Veal. Ratio. 
sq. cm. em. 
CAUCASIAN Ia G taeteleeicls ie leterstoiers 54 7.02 1302 54 
Negro male ...... qaoccsdehons 50 6.27 1208 a2 
Caucasian (female! in 3 vcicterc-1-- 14 6.40 1087 59 
INEST ORLeTINAl eis cis)-cclcete tetas rect 26 5.68 1064 53 
The average brain weight is greatest in the Caucasian male, least in 
the Negro female, and intermediate in the Negro male and the Caucasian 
female. The average cross section area of the corpus callosum is rela- 
tively the same, with the Negro male and the Caucasian female transposed 
in relation to each other. The ratio of area to weight is greatest in the 
Caucasian female, least in the Negro male, with the Negro female and 
the Caucasian male respectively a little higher than the Negro male; but. 
the ratio of the Caucasian female is hardly a fair one, because so few 
brains of this kind are examined, and they are from such varied sources, 
and with so many methods of preservation. The relation of the anterior 
and posterior lineal halves of the corpus callosum exhibits a greater racial 
difference. This is perceived by a glance at Chart VI, compiled from 
Table VI in a manner similar to that of the charts previously presented. 
The corpus callosum is divided into halves of equal length by a line per- 
pendicular to the brain axis, at a point intermediate between two lines. 
perpendicular to the brain axis, dropped from each end of the corpus 
callosum. It is hardly necessary to do more than point out the racial 
difference indicated in the chart, because it is so plain, even to a casual 
observer. There is not an absolute separation of the races, but there is a 
decided difference. In general, as the area of one end of the corpus 
callosum increases, the other increases also, but the increase in area of the 
anterior end is greater in the Caucasian than in the Negro, while the in- 
crease in the area of the posterior end is greater in the Negro than in the 
