  It is shown (1) that Lanczos's quaternionic formulation of Dirac's equation
does not lead to a solution of the problems that plague the standard spin 3/2
theory based on the Rarita-Schwinger equation, but (2) that the four-component
solutions to the quaternionic generalization of Dirac's equation proposed by
Lanczos in 1929 may provide a consistent theory for spin 3/2 particles,
although at the cost of giving up the postulate that there should be a
one-to-one correspondence between arbitrary-high-spin unitary representations
of the inhomogeneous Lorentz group and elementary particles.
