Influence of the Nervous System 679 
No. 14.19. g mm. of the cord destroyed: ‘Time, 62 days. 
No. 14.2. 19 mm. of the cord destroyed. ‘Time, 97 days. 
No. 15.3. 6mm. of the cord destroyed. ‘Time, 101 days. 
In 14.8, 11 mm. of the cord were removed. Preserved after 
156 days. ‘The cord contained a degenerate fibrous layer anterior 
to the 11th mm. Posterior to this level the cord was double 
until the roth mm. Beyond this there was no cord whatsoever. 
The next three animals showed unmistakable evidence that 
the nerve cord had regenerated, towards, but not quite to the ampu- 
tated end. No new tails developed. 
No. 14.18. Amputated about the middle of the tail. Destroyed 
7 mm. of the cord by means of a glass capillary. “Time, 124 days. 
Anterior to thegthmm.,the nerve cord was quite normal. From 
this level, extending to 1 mm. from the end, there was a tapering 
nerve cord that corresponded in every detail with regenerated cords 
already described. ‘The fibrous layer had degenerated from the 
broken end anteriorly about 2 mm., and a new cord had regener- 
ated posteriorly about $8 mm., during the 124 days. 
Nostra tc otump,: ti mm. lone. lime; 177 days. | The 
cord was normal until 104 mm. from the amputated end, where 
the cord becomes considerably thinner, and gives rise to the new 
cord. ‘This becomes still more diminutive posteriorly, and ends 
altogether about 4 mm. from the amputated end. 
No. 1.15. Stump, 20 mm. long. Destroyed 8 mm. of the 
cord. ‘Time 126 days. 
The cord was continuous to the very end of the tail, i1.e., tothe 
amputated end. ‘The changes between the old and the new cord 
were so gradual and subsequent regeneration had concealed the 
traces of former degeneration so completely, that it was quite 
impossible to state where one began and the other ended. 
If enough time be allowed and if circumstances be favorable we 
might expect that the nerve cord would reach the amputated end 
and thus permit regenerationtotake place. ‘Thisactually occurred. 
In 15.4, 8 mm. of the cord was destroyed. ‘Time, 72 days. 
The regenerated cord extended from about 8 mm. to the ampu- 
tated end. All tails form a cap of “embryonic” tissue over the 
amputated end. In this animal also, the cap had formed, but was 
