FASCICULUS CEREBRO-SPINALIS IN THE RAT 



421 



axons had disappeared. Figure 10 illustrates the appearances 

 seen in these sections. It will be observed that the posterior 

 funiculus on the left side of the drawing is considerably smaller 

 than that on the right and contains a degenerated area (a) reach- 

 ing from the surface of the cord to the interval between the two 

 pyramidal fasiculi; The area occupied by large undegenerated 

 medullated fibers on the left side (b) is about one-half that on 

 the right. But there is no clearly marked decrease in the size 



Xo.tKo^Tin.£ HiH ("ilZ, 



Fig 10 Part of a section through the lumbar portion of the spinal cord showing 

 degeneration, a, in the cuneate fasciculus. Undegenerated portion of the 

 cuneate fasciculus, h; gray substance c. Ocu. 3, Obj. 3. 



of the pyramidal fasciculus nor any noticeable degeneration of 

 the axons within its area. 



In order to compare more accurately the areas occupied by the 

 pyramidal fasciculi on the normal and operated sides, these 

 areas were roughly computed in sixteen successive sections. This 

 was done by tracing the outlines of the tracts with the camera 

 lucida on millimeter paper, and determining the number of square 

 millimeters covered by the areas thus projected. It was found 

 that the tract on the operated side was 3 per cent smaller than that 



