336
The Body Electric
Before I began, I had to solve a technical problem with the electrodes.
Even two wires of the same metal had little chemical differences, which
gave rise to small electrical currents that could be misinterpreted as
coming from the animal. Also, the slightest pressure on the animal's
skin produced currents. No one understood why, but there they were. I
found descriptions in the older literature of silver electrodes with a layer
of silver chloride applied to them, which were reported to obviate the
false interelectrode currents. I made some, tested them, and then fitted
them with a short length of soft cotton wick, which got rid of the
pressure artifact. When I wrote up my results, I briefly described the
electrodes. Afterward I received a call from a prominent neu-
rophysiologist who wanted to visit the lab. "Very nice," I thought.
"Here's some recognition already." He was particularly interested in
how the electrodes were made and used. Some months later, damned if I
didn't find a paper by my visitor in one of the high-class journals, de-
scribing this new and excellent electrode he'd devised for measuring di-
rect-current potentials!
A couple of years later, while Charlie Bachman and I were looking for
the PN junction diode in bone, I was asked to give a talk on bone
electronics at a meeting in New York City. The audience included engi-
neers, physicists, physicians, and biologists. It was hard to talk to such a
diverse group. The engineers and physicists knew all about electronics
but nothing about bone, the biologists knew all about bone but nothing
about electronics, and the physicians were only interested in therapeutic
applications. At any rate, I reviewed some bone structure for the phys-
icists and some electronics for the biologists, and then went on to de-
scribe my experiments with Andy Bassett on bone piezoelectricity.
I probably should have sat down at that point, but I thought it would
be nice to talk about our present work. The rectifier concept was tre-
mendously exciting to me, and I thought we might get some useful
suggestions from the audience, so I described the experiments showing
that collagen and apatite were semiconductors, and discussed the im-
plications. After each talk a short time was set aside for questions and
comments, generally polite and dignified. However, as soon as I fin-
ished, a well-known orthopedic researcher literally ran up to the
audience microphone and blurted out, "I have never heard such a collec-
tion of inadequate data and misconceptions. It is an insult to this au-
dience. Dr. Becker has not presented satisfactory evidence for any
semiconducting property in bone. The best that can be said is that this
material may be a semi-insulator."
Semiconductors are so named because then properties place them be-