The Ticklish Gene
129
THE LIGHT TEST CONFIRMS BONE'S ELECTRICAL SYSTEM
WOLFF'S LAW CONTROL SYSTEM
Collagen fibers are formed from long sticks, like uncooked spaghetti,
of a precursor molecule called tropocollagen. This compound, much
used in biological research, is extracted from formed collagen—often
from rat tails—and made into a solution. A slight change in the pH of
the solution then precipitates collagen fibers. But the fibers thus formed
are a jumbled, feltlike mass, nothing like the layered parallel strands of
bone. However, when we passed a weak direct current through the
solution, the fibers formed in rows perpendicular to the lines of force