DEGENERATION AND REGENERATION OF NERVES 



91 



conclusion that regeneration in the medullated fibers of the cord 

 of the rice-fed fowls fails to take place. 



Regeneration in the cord was included in this study because, 

 after regeneration had been shown to take place in the peripheral 

 nerves by an outgrowth of the axis cylinder into the old medul- 

 lary sheath and in the absence of the embryonic nerve fiber, no 

 reason was now apparent why the same thing could not occur 

 in the fibers of the cord as well. According to the majority of 

 investigators, regeneration in the fibers of the cord is, to say the 

 most, doubtful. Schafer ('08) declares "regeneration does not 

 occur within the central nervous system, or at most in a very 

 incomplete manner. This fact may be associated with the cir- 

 cumstance that the fibers within the spinal cord and brain have 

 no nucleated sheath of Schwann, and the conducting path which 

 the cells of this sheath form in the peripheral nerves for the out- 

 growing axis cyhnders is therefore absent." According to Halli- 

 burton ('07), as noted above, the neurilemma is 'non-existent' 

 in the medullated fibers of the central nervous system and ''as 

 is well known, regeneration does not occur" in these fibers. But 



TABLE 1 



Showing degeneration in the lumbosacral cord at time of paralysis and after 



recovery 



^ The cord of this fowl also contained a great many fibers which appeared con- 

 siderably swollen and which are not included in this count. 



