130 NAOKI SUGITA 
If the length of the average diameters represents relatively the 
cube root of the volume of the cell body or of the nucleus, the 
actual volume of them may be comparable among themselves 
by the cube of the diameters. It is clearly seen from the chart 
that the pyramids in the lamina pyramidalis of the Albino cortex 
attain their maximum size in a brain weighing from 1.1 to 1.8 
erams or 20 to 30 days in age, the curve showing the maximum 
size in a brain weighing about 1.25 grams, and after that they 
diminish slightly but steadily in size as the age (brain weight) 
advances, while, on the other hand, the ganglion cells in the 
lamina ganglionaris attain nearly their full size in a brain weigh- 
ing about 0.95 gram or ten days in age; that is, earlier than the 
pyramids, and after that slowly but steadily increase their size 
as the brain weight increases. The nuclei in the pyramids and 
in the ganglion cells change their sizes in much the same way 
as the cell bodies to which they belong, the graphs for the cell 
body and that for the nucleus for each kind of cell running nearly 
similar courses (chart 1). 
As shown in chart 1, the graphs suggest that both kinds of cells 
increase in size very rapidly during the first ten days after birth, 
and then the rate diminishes rather abruptly during the following 
ten days (0.95 to 1.15 grams in brain weight) or more, at the 
end of which phase the pyramids reach the maximum size, 
after which they decrease slowly, while the ganglon cells still 
continue to increase somewhat even after this phase. 
On examining all the sections which I made, it was seen that 
the ground tone of the sections uniformly stained with the 
carbol-thionine has been gradually changing as the age of the 
brain, from which the sections were taken, increases. In suc- 
cessfully stained sections—even if stained by decoloration—of 
brains from birth to those weighing less than 1.0 gram, the 
ground tone is rather purple or violet, when viewed with the 
naked eye by transmitted light. On the other hand, the sec- 
tions from brains weighing more than 1.3 grams have a rather 
distinetly blue tone. The intercellular tissue takes more easily 
the pale blue color—owing to a less decoloration—in older 
brains, while in younger brains the intercellular tissue remains 
