Robert Bennett Bean_ 369 
That these differences are manifested not only in mass, and by aver- 
ages, but individually, may be determined by examining Table I, and 
Charts I and II, taken from the numbers in Table II, and giving the 
relation of the anterior and posterior association centers in each brain. 
The anterior association center in all cases is represented by the numbers 
from the column under 60°, the posterior association center by the num- 
bers from the column under 120°. The charts are made up by the use of 
ordinates and abscisse, the former representing the length of the radii 
of the anterior association center, the latter the length of the radii of 
the posterior association center. An arbitrary line drawn on the charts 
from the 68-mm. ordinate on each side divides the symbols into racial 
groups, the Caucasian above the line and the Negro below, indicating a 
longer radius to the anterior association center in a larger number of 
brains among Caucasians. This line divides the two sides differently. 
On the left side a larger number of Caucasian symbols fall below the 
line and a larger number of Negro symbols fall above the line than on 
the right side. The symbols that are over the line represent the extremes 
of each race in relation to the other race. A greater number of Negro 
extremes have a larger left anterior association center, and conversely, 
a greater number of Caucasian extremes have a smaller left anterior as- 
sociation center. The extremes may be represented by a table taken from 
Charts I and II. 
TABLE IIb. 
EXTREMES OF THE ANTERIOR ASSOCIATION CENTER. 
Left Side. Right Side. 
a {A 
Sanbols Above the Below the Above the Below the 
y ° arbitrary line. arbitrary line. arbitrary line. arbitrary line. 
@WaMGASTAN) 2.5 ales oe stesis se 24 16 Dine 11 
INGETO® ace are-eis ove teisans exes) s/o. 15 45 10 50 
The numbers in this table are of value only in comparing the two 
sides of the body. On the left side there are 16 Caucasian extremes and 
15 Negro extremes. On the right side there are 11 Caucasian extremes 
and 10 Negro extremes. The deduction from this is that there is greater 
dissimilarity of the brains of the two races on the right side than on the 
left side. The majority of the Negro symbols fall below the line, and 
the majority of the Caucasians fall above on each side, this being the 
most noticeable difference, that the anterior association is smaller in the 
Negro than in the Caucasian. The radius to the anterior association 
center of the left hemisphere invariably passes over the gyrus frontalis 
inferior, so that this may mean a greater development of the gyrus in the 
28 : 
