The Embryo at the Wound 57
each nerve fiber bundle reached the end of the stump, it broke up and
each fiber went its separate way, snaking into the epidermis, which
might be five to twenty cells thick. Each nerve fiber formed a tiny bulb
at its tip, which was placed against an epidermal cell's membrane, nest-
ling into a little pocket there. The arrangement was much like a syn-
apse, although the microscopic structure wasn't as highly developed as
in such long-term connections.
The junction was only a bridge, however. The important question
was: What traffic crossed it?
In
1946, Lev Vladimirovich Polezhaev, young Russian biologist
then working
in
London, concluded a long series of experiments in
which he induced partial regeneration in adult frogs, the same success