TRANSPLANTATION OF CEREBRAL CORTEX SID 
what fragmented, especially the free endings of the medullated 
nerve fibers which easily fray. The blood supply is less ample 
in such regions, the capillaries being more slender and less well 
filled. 
THE MASSING OF CORTICAL FIBERS 
In addition to what we may regard as true transplantation of 
cerebral cortex, other interesting results of the operations were 
noted. One of these was reported at a joint meeting of the 
Chicago Neurological Society and the Biological Club of the 
University of Chicago, March 30, 1909, under the title “‘On the 
course of cortical tangential fibers developing after ablation of 
encephalic cortical substance.’ Perhaps the use of the term 
‘tangential’ in this connection is misleading. The fibers to 
which the report refers were parallel to the surface of the brain 
and located at various depths throughout the cortex. They 
were not tangential in the narrower sense of the term as it is 
applied to the fibers lying near the surface of the cortex. Ata 
later time it was noted in other brains that vertical fibers were 
also apparently increased in number. The materials in which 
these conditions were noted were produced in the following way. 
When the operator accidentally opened into the lateral ventricle 
in the course of operation, there was a tendency for the sub- 
ventricular substance to protrude through and to widen the 
original opening. It was while studying serial sections of a brain 
in which this had occurred that the apparent increase of fibers 
about the open space was noted. In the normal cerebral cor- 
tex of the albino rat many scattered medullated nerve fibers 
may be found at various depths running parallel to the surface 
of the cortex. In those brains in which considerable openings 
occurred, there appeared, in transverse serial sections, to be a 
massing of fibers parallel to the cortex. These bands of fibers 
could be traced from outlying cortex and were found to merge 
into cerebral tissue which had about the normal number of fibers 
which were parallel to the surface. It seemed at the time that 
neuron processes which in their growth were not able to follow 
the path usual to them had been deflected by the wall of the 
