342 THe MICROSCOPE, 
removed from the brain a small pasteboard or wooden peg bear- 
ing a number was inserted, and the reaction produced at this 
point was carefully recorded upon a diagram of the surface of 
the hemisphere with the corresponding number attached. After 
the removal of the brain these tags served to check the accuracy 
of the diagram, and a careful drawing was made including the 
areas experimented on. *: 
The brains were placed in chrom-acetic solution for twenty- 
four hours and then in alcohol, and continuous series of sections 
in various directions mounted in balsam. Several hundred such 
sections were prepared and studied by the method of geometric 
reconstruction from camera drawings and measurements. 
To briefly summarize the facts elicited upon this point, it may 
first be stated that over the entire recognized motor area and 
along the limbic lobe, or region along the median fissure, a well- 
defined type of structure can be observed, while the remainder 
of the cortex contains an entirely different set of cells. In the 
motor area the cortex resembles that described by Bevan Lewis 
in the sheep and pig, though the minor subdivisions are less 
distinct. The outer neuroglia layer is followed by a zone of 
small pyramidal cells with a strong axial process derived from 
the superficial layer, and fine anastamosing fibrils from the lower 
and blunt extremity. Below this is an indistinct layer of fusi- - 
form cells, which connect below with the “giant” or ganglion 
; g gang 
cells, which are not only more than twice as large as the other 
members of the series, but are nested or clustered and have 
peculiarities of form readily distinguishing them. The axial 
process is strong and may be traced upward for a considerable 
distance. The numerous inferior processes of these giant cells 
g 
connect with multipolar, parametric, or irregular cells lying upon * 
or imbedded in the white fibre zone. Occasional anastamosing 
of cells of the same level can be detected, but the connection 
seems to be between cells of different orders. 
Directing attention to the cortex in portions known to lie 
within the sensory area, an entirely different type of cell arrange- 
ment was found. In general, the sensory, or preferable (not to 
prejudice their function) centripetal, cells receive the stain less 
readily and are only visible in good preparations; but distine- 
tions based on receptivity to stain are untrustworthy. The 
cells of the upper zone lying next the neuroglia layer are nearly 
