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The Body Electric
Even if we could supply the proper electrical stimulus, we weren't
sure there would be any cells able to respond to it. Mammalian red
blood cells had no nuclei, so they couldn't dedifferentiate. Based on our
work on bone healing in frogs, we suspected that immature red corpus-
cles in the bone marrow might take over, but perhaps they were pro-
grammed to dedifferentiate only for fracture healing. Even if they would
respond to an external current, we wondered whether there were enough
of them to do the job.
There was also the problem of complexity. Many regeneration re-
searchers believed that mammalian tissues had become so specialized and
complicated that they'd simply outgrown the control system. Maybe it
couldn't handle enough data to fully describe the parts needed. If so, any
blastema we produced would just sit there, not knowing what to make.
A First Step with a Rat Leg
I tested the kind of silver-platinum couplings Smith used and found
they delivered several times too much current for ideal dedifferentiation,
according to our frog experiments. Joe Spadaro, another of Charlie's grad
students, suggested that we put carbon resistors between the two met-
als, giving us devices of various current levels.
In 1971, Joe and I amputated the right forelegs of thirty-five rats.
We made the cuts through the upper foreleg well away from the elbow
so that only the bone shaft, which had long ago ceased growing, would
remain at the tip. We used all males, to obviate as many hormonal
variables as possible. As controls we treated some of the stumps with no
device, or one made of a single metal, or one with the silver positive end
facing the stump. We did the actual test on twenty-two of the rats,
implanting our batteries with the negative platinum electrode at the
wound. We tucked the outer electrode into the marrow cavity and
sutured the inner one to the skin of the shoulder.
We had an answer fast. After three days the stumps of the controls had
begun to heal over or even, in the case of the highest-current couplings,
die back a little behind the amputation line. But the experimental legs
with our medium-current devices, supplying 1 nanoamp, were doing
well. In a week, nearly every one had a well-formed blastema and seemed
ready to replace the whole limb.
Since healing is very fast in rats, and because we wanted a uniform
sample for our
first test,
we sacrificed all of the controls and most
of
the
test animals at this time, although we spared a few for a month. We cut