124 NAOKI SUGITA 
are given in table 2, and here also only the averages for the 
brain-weight groups are given.! 
The maximal diameters of the nuclei of the same cells were 
measured in the two directions in which the cell measurements 
were made. The nuclei have sharp contours, so that it Was al- 
Ways easy to find the border points of the diameters. The re- 
sults of the nuclear measurements have been treated in the same 
manner as the cell-body measurements and the average values 
are recorded also in the same way—without any correction—in 
tables 1 and 2. 
In table 3 the final average diameters of the cell bodies and 
their nuclei for each brain-weight group are given for each sec- 
tion. These final average values were obtained by multiplying 
the values of the transverse and longitudinal diameters together 
and by extracting the square root of the product, thus assuming 
the cell- and nucleus-figures to form a plane instead of a solid 
body. By this treatment, the results for the nucleus do not differ 
much from those which would be obtained by using a planimeter, 
because the nucleus has a nearly spherical or ellipsoidal form. 
The cell body, on the contrary, appears as a somewhat irregular 
cone or pyramid in the outline. Nevertheless, its relative vol- 
ume may be denoted by a’b, or its area by ab, in which a is the 
transverse and 6 the longitudinal diameter. Accordingly, the 
relative values of the average diameter may be represented by 
Vab, but these values should not be compared directly with 
the average diameter of the nucleus, because the forms of the cell 
body and of the nucleus are quite different. The size of cell 
bodies and their nuclei was assumed to have shrunken in the 
same proportion as the total brain volume during the procedure 
of fixation, imbedding and mounting and the values observed 
were therefore corrected for the fresh condition of the material 
by the use of the correction-coefficient which was formerly used 
for the correction of the cortical thickness or other measure- 
ments made on the same section. The cell bodies and nuclei 
Were assumed to have shrunken similarly in transverse and 
‘The detailed data for tables 1 and 2 and also for tables 6 and 7 have all 
been tabulated and are on file at The Wistar Institute of Anatomy and Biology. 
