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EXPLANATION OF FIGURES. 
PLATE VIi. 
Figs. 1-4. Photo-micrographs of frontal sections of the left cerebral hem- 
ispheres of rats, showing the position of the scar and the general appearance 
of the surrounding parts. Sections 45 stained by the PAL-WEIGERT technique. 
The cut is indicated by ‘‘c’’. The scar is seen as a light band, medial to which 
the fibers are numerous, and lateral to which they are less abundant. 
Fig. 7. From Rat No. 1, operatedon when twenty-one days old and killed 
53 days later. 
Fig. 2. From Rat No. 2, operated on when 7 days old and killed 42 days 
later. Showing aggregation of fibers in the scar in the ventral part of the cor- 
tex just above the sharp notch on the ventral surface. Notice that the sear has 
been distorted by the shifting of the areas of the cortex with reference to 
each other. 
Fig. 3. From Rat No. 3, operated on when 3 days old and killed 41 days 
later. Notice the complete disappearance of the corpus callosum lateral to 
the injury. 
Fig, 4. From Rat No. 4, operated on when 0.5 day old andkilled 40 days 
later. Notice the degeneration of the corpus callosum on both sides of the 
lesion. 
Fig. 5. Camera lucida tracing of the fibers in and about a small area of 
the scar (Rat No. 1) seen in Fig. 1, taken at a point about one-third of the way 
from the corpus callosum to the surface of the cortex. The arrow indicates 
the path of the knife, and ‘‘f”’ a fiber crossing the scar. 
Fig. 6. Camera lucida tracing of the fibers in and about a small area of 
the scar (in Rat No. 3) seen in Fig. 3, taken at a point about one-third of the 
way from the corpus callosum to the surface of the cortex. The arrowand ‘‘e”” 
have the same significance as in the preceding figure. The fibers in the scar 
are slightly more abundant than in Fig. s. 
Fig. 7. Drawing of the area of scar tissue (Rat No. 4) seen in Fig. 4, 
