Influence of the Nervous System 673 
2d mm. and the cut end the whole of the cord was destroyed. 
Reparative changes of the cord not unlike those mentioned in con- 
nection with partially paralyzed legs have taken place. ‘The point 
of especial interest is the absence of the cord from the end coupled 
with the lack of regeneration. 
In this particular animal there was a peculiar growth of cartilage, 
at the injured end, which forming an irregular mass practically 
plugged the end of the neural arch. This plug it might be sup- 
Fig. 5 Cross-section of nerve cord a short distance anterior to amputated level. Illustrates extent 
of degeneration anterior to cut end. Cellular layer reduced. Fibers disintegrated most completely 
in the ventral or motor parts. 
posed may have had something to do with the lack of regeneration 
of the tail. 
No. 1.11. Tail amputated near the distal end; 4 mm. of the 
nerve cord removed. After 32 days no regeneration. The nerve 
cord was normal as far as 54 mm. from the end. From this level 
to about 44 mm. the myelin of the fibrous layer shows an increas- 
ing granulation. At the latter level the cord looks not unlike 
Fig. 5. From this point to about 1 mm., there is a marked shrink- 
age. [he disintegrated and vacuolated fibrous layer has given 
