[en] In A₀ = 0 gauge in QED, the Ward--Takahashi identity implies the nonpropagation of the Fermi field psi. This is shown to be a valid conclusion, both by using functional integration and by perturbation theory. Since Green's functions are gauge dependent, this does not however imply the immobility of spin-1/2 fields. Two types of composite fields are exhibited for which the field psi is dressed with longitudinal, nonobservable photons. For these fields, no implications about their propagators can be drawn from the W--T identity, which for these is trivially zero. It is shown by functional integration and by perturbation theory that these fields can propagate, and interact with the photon field with the usual P(1/k/sub o/sup 2) factor of A₀ = 0 gauge