  It is usually supposed that the Dirac and radiation equations predict that
the phase of a fermion will rotate through half the angle through which the
fermion is rotated, which means, via the measured dynamical and geometrical
phase factors, that the fermion must have a half-integral spin. We demonstrate
that this is not the case and that the identical relativistic quantum mechanics
can also be derived with the phase of the fermion rotating through the same
angle as does the fermion itself. Under spatial rotation and Lorentz
transformation the bispinor transforms as a four-vector like the potential and
Dirac current. Previous attempts to provide this form of transformational
behaviour have foundered because a satisfactory current could not be
derived.(14)
