Four
Life's Potentials
It's an axiom of science that the better an experiment is, the more new
questions it raises after it has answered the one you asked. By that stan-
dard my first simple test had been pretty good. The new problems
branched out like the fingers on those restored limbs: Where did the
injury currents come from? Were they in fact related to the nervous
system and, if so, how? It seemed unlikely that they sprang into action
only after an amputation; they must have existed before. There must
have been a preexisting substratum of direct current activity that re-
sponded to the injury. Did the voltages I measured really reflect such
currents, and did they flow throughout the salamander's body? Did
other organisms have them? What structures carried them? What were
their electrical properties? What were they doing the rest of the time,
before injury and after healing? Could they be used to provoke regenera-
tion where it was normally absent?
I had ideas about how to look for some of the answers, but, to under-
stand my approach, the reader unfamiliar with electrical terms will need
a simplified explanation of several basic concepts that are essential to the
rest of the story.
Everything electrical stems from the phenomenon of charge. No one
knows exactly what this is, except to say that it's a fundamental property
of matter that exists in two opposite forms, or polarities, which we
arbitrarily call positive and negative. Protons, which are one of the two
main types of particles in atomic nuclei, are positive; the other particles,
the
neutrons,
are
so
named because rhey
have
no
charge.
Orbiting
around the nucleus are electrons, in the same number as the protons