580 ELIZABETH HOPKINS DUNN 
Ranson interpreted these fibers as processes of neurons which 
were immature at the time of operation. Their perikarya may 
be located at some distance from the cicatrix. At F’,, in figures 
7 and 8, may be noted such medullated nerve fibers crossing 
cicatricial tissue in the cerebral cortex of an albino rat. 
Fig. 7 Showing a section of the brain of the albino rat from a region near 
the posterior pole. In the dorsal part of the left hemisphere is a light line (L) 
marking the line of incision, with a few medullated nerve fibers crossing it (F). 
From sections 81-82, Series IV, Group IV, Rat 3. X 6. 
SUMMARY 
By the use of immature nervous tissue from the brain of the 
albino rat the life of the constituent neurons in the cerebral 
cortex has been maintained after transplantation. 
After many unsuccessful attempts this result was obtained by 
utilizing a thin covering blood clot to retain the graft in position. 
The best nourished grafts were those which lay near the plexus 
choroideus of the lateral ventricle. 
In the neurons of the transplanted cortex certain differences 
from those of normal tissue were detected. These differences 
were in the staining intensity and morphology of the perikarya 
and medullated fibers. The blood supply was less ample. 
