fixed brain was embedded in ether-alcohol for a few hours and
then a succession of ether-alcohol and celloidin mixtures of
increasing viscosity, until the brain was suspended in a hard
of thin sections (25-40 microns thick) were sectioned sequentially
from this celloidin block. Each brain was sectioned serially
using a standard sliding microtome. Most specimens were sectioned
in a coronal plane. A few specimens were sectioned horizontally
and a few were sectioned sagittally.
Alternate sections were then stained with thionin to stain nerve
cell bodies, or hematoxylin to stain the myelin sheaths of nerve
fibers (axons). The sections were stained according to an evolving
recipe perfected over the years by the chief histologist, depending
on the age and size of the specimen.
The cell-stained series were mounted on one set of slides and
the fiber-stained series were mounted on another set of slides.
All mounted sections were covered with thin cover slips and
allowed to dry. They were then placed back to back in brain
slide boxes, arranged from front to back (rostro-caudally, medio-laterally,