Influence of the Nervous System 655 
begun to degenerate and the degeneration increases centrally, so 
that next to the ganglia many fibers have disintegrated completely. 
Others, though separated by spaces, are quite normal. These 
facts mean that the nerve fibers have degenerated from two separate 
centers, from the amputated end of the leg proximally, and from the 
spinal column centrifugally. In this particular animal the two 
degenerating processes have come closer together than in any of 
the preceding instances. It should be borne in mind that while 
Fig. 3 Longitudinal section of large nerve in hind leg, showing typical Wallerian degeneration 
Upper part close to the knee, the lower, near amputated level. 
centripetal degeneration includes all fibers of the nerve bundle, 
degeneration in the opposite direction affects the motor fibers only. 
The nerve cord was absent in the tail and plexus region and for 
2 mm. anterior to the plexus. 
No. 1.30. Amputated eleven days after paralysis. Preserved 
toi days later. Legs had in the meantime grown 4 mm. long and 
differentiated 4 toes. Conditions were like those in No. 1.58.. 4 
No. 1.39. Right hind leg amputated eleven days after paralysis. 
