The vanishing of the renormalized charge used so successfully in qurantum electrcdynamics is due to the singularity of the pronagator being not less than that of the free field near the light cone. The connection between the canonical formalism and the singularity of the one-bedy propagator is derived, being restricted to the interaction of the spinor and boson fields, and it is shown that no hamiltonian exists for this interaction. It is concluded that an interaction for which there is no hamiltonian is needed to smooth out the renormalization theory. The possibility of weakening the propagator singularity by the gravithtional field is discussed. (D.L.C.)