The Ticklish Gene
133
experiment: When we added together the free electrons of collagen and
apatite, we fell short of the number we found in whole bone. That made
us certain that we were washing out some trace mineral.
We decided to work backward. We prepared a solution containing
small amounts of a wide variety of metals. Then we soaked our collagen
and apatite cubes in this broth to see what they'd pick up.
We knew we were on the way to solving this mystery when we exam-
ined the results. Only a few of the metals had bonded to the bone mate-
rials: beryllium, copper, iron, zinc, lead, and silver. The diameters of all
the absorbed atoms were exact fractions of one another. The results
showed that the bonding sites were little recesses into which would fit
one atom of silver or lead, two of iron or copper or zinc, or six of
beryllium.
Only one of these metals gave us an electron resonance of its own,
indicating that it had a large number of free electrons that could affect
the electrical nature of bone. That metal was copper. We made a batch
of broth containing only copper. We expected that copper's EPR signal
would change to one value as it bonded with collagen, and to another as
it bonded with apatite. Since the molecular structure of each was quite
different, we figured that each would bind copper in a different way.
We could hardly believe the results. Bonding had indeed changed
copper's resonance, but the change was the same in both materials. By
analyzing it we deduced that each atom of copper fit into a little pit,
surrounded by a particular pattern of electric charges, on the surface of
apatite crystals and collagen fibers. Because the pattern of charges was
the same in both materials, we knew that the bonding sites were the
same on both surfaces and that they lined up to form one elongated
cavity connecting the crystal and fiber. In other words, the two bonding
sites matched, forming an enclosed space into which two atoms of cop-
per nestled. The electrical forces of this copper bond held the crystals
and fibers together much as wooden pegs fastened the pieces of antique
furniture to each other. Furthermore, the electrical nature of peg and
hole suggested that we had found, on the atomic level, the exact loca-
tion of the PN junction.
This discovery may have some medical importance. The question of
how the innermost apatite crystals fasten onto collagen had eluded
orthopedists until then, and the finding may have opened a way to un-
derstand osteoporosis,a condition in which the apatite crystals fall off
and the bone degenerates. The process is often called decalcification,
although more than calcium is lost. It's a common feature of aging. I
surmise that osteoporosis comes about when copper is somehow removed