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The Body Electric
trons cascaded step by step down a staircase of molecules, losing energy
with each bounce. The main difference was that in protein semiconduc-
tion the electrons' energy would be conserved and passed along as infor-
mation instead of being absorbed and stored in the chemical bonds of
food.
With Szent-Gyorgyi's suggestion in mind, I put together my working
hypothesis. I postulated a primitive, analog-coded information system
that was closely related to the nerves but not necessarily located in the
nerve fibers themselves. I theorized that this system used semiconduct-
ing direct currents and that, either alone or in concert with the nerve
impulse system, it regulated growth, healing, and perhaps other basic
processes.
Testing the Concept
The first order of business was to repeat Burr's measurements on sala-
manders, using modern equipment. I put the reference electrode at the
tip of each animal's nose and moved the recording electrode point by
point along the center of the body to the tip of the tail, and then out
along each limb. I measured voltages on the rest of the body and plotted
lines of force connecting all the points where the readings were the
same.
Instead of Burr's simple head-negative and tail-positive form, I found
a complex field that followed the arrangement of the nervous system.
There were large positive potentials over each lobe of the brain, and
slightly smaller ones over the brachial and lumbar nerve ganglia between
each pair of limbs. The readings grew increasingly negative as I moved
away from these collections of nerve cell bodies; the hands, feet, and tip
of the tail had the highest negative potentials.
In another series of measurements, I watched the potentials develop
along with the nervous system in larval salamanders. In the adults, cut-
ting the nerves where they entered the legs—that is, severing the long
nerve fibers from their cell bodies in the spinal cord—wiped out the
limb potentials almost entirely. But if I cut the spinal cord, leaving the
peripheral nerves connected to their cell bodies, the limb potentials
didn't change. It certainly looked as though there was a current being
generated in the nerve cell bodies and traveling down the fibers.
To have a current flow you need a circuit; the current has to be made
at one spot, pass through a conductor, and eventually get back to the
generator. We tend to forget that the 60-cycle alternating current in the