688 A. F. Goldfarb 
gives rise to a pair of nerves that innervate the region occupied by 
the next two or three posterior vertebra. Inthe tadpole however, 
though the cord extends almost to the tip of the tail, the dorsal gang- 
lia and the paired nerves originate in the proximal half of the tail, 
Fig. 8.. In the tadpole from which Fig. 8 was reconstructed, 
the tail was 29 mm. long, the ganglia were only in the anterior 15 
mm., leaving the last 14 mm. without ganglia. The nerves in the 
Bat proper are segmentally arranged as in Diemyctylus, but in 
the tail the nerves grow more BH more posteriorly so that the 
anterior region of the cord innervates the posterior parts of the 
tail. 
Therefore in order to remove nerve stimuli from the amputated 
end, it becomes necessary not only to remove the cord and dorsal 
ganglia near the end but practically from the whole tail. 
Various efforts were made to perform such an operation. ‘The 
broach was used as in the newt experiment. But as there is 
no bony neural arch to guide the broach, it waslargely a matter of 
chance whether the whole of the cord was removed or not. 
Another more satisfactory method consisted in slitting the side of 
the tail, exposing the notochord and overlying nerve cord, and then 
to cut or burn out the latter. Other methods, while they succeeded 
in removing the whole of the cord involved so much injury that 
the animals died. 
After the effects of the anzsthesia, the Bete swam around 
moving their tails considerably. Externally it was impossible to 
make certain whether these movements were due to motor activity 
in the tail proper or resulted from movements in the base or body 
region. New tails appeared on both control and operated animals. 
Many of these were examined in serial section. The marvellous 
power of repair together with the simple character of the cord, 
make it almost impossible at times to state with certainty whether 
a cord is a regenerated one, or an injured cord that has completed 
itself, or the original non-mutilated cord (in distal regions). 
One example may serve to illustrate the essential points: 
No. 17. Length of tail 37 mm., removed 25 mm., broach used 
to destroy the cord. 35 days later the new tail was 6 mm. long. 
Measuring from the amputated end, the nerve cord was appar- 
