  The tunneling splitting of the energy levels of a ferromagnetic particle in
the presence of an applied magnetic field - previously derived only for the
ground state with the path integral method - is obtained in a simple way from
Schroedinger theory. The origin of the factors entering the result is clearly
understood, in particular the effect of the asymmetry of the barriers of the
potential. The method should appeal particularly to experimentalists searching
for evidence of macroscopic spin tunneling.
