  We reconsider the question of wave function renormalization in heavy fermion
effective field theories. In particular, we work out a simple and efficient
scheme to define the wave function renormalization with respect to the lowest
order heavy fermion propagator. The method presented is free of a set of
ambiguities which arise in heavy fermion effective field theories. In this
context, we discuss the approaches used in the literature so far. We also
calculate the fourth order pion mass contribution to the nucleon mass shift and
discuss the tree and loop contributions to the electric Sachs form factor of
the nucleon.
