98
The Body Electric
THE HUMAN DC FIELD PATTERN
At the same time, to see whether the current of injury and the surface
potentials came from the same source, I made electrical measurements
on salamander limbs as they healed fractures. (As mentioned in Chapter
1, bone healing is the only kind of true regeneration common to all
vertebrates.) The limb currents behaved like those accompanying re-
growth. A positive zone immediately formed around the break, although
the rest of the limb retained at least part of its negative potential. Then,
between the fifth and tenth days, the positive zone reversed its potential
and became more strongly negative than the rest of the limb as the
fracture began to heal.
Next I decided to follow up Burge's experiments of two decades be-
fore. I would produce various changes in the state of the nervous system
and look for concomitant changes in the electrical measurements. To do
this
right
I
really
needed a
few thousand dollars for an
apparatus that
could take readings from several electrodes simultaneously and record
them side by side on a chart. My chances of getting this money seemed