The anomalous threshold discontinuities of the deuteron form factors are calculated by an extension of Cutkosky’s method to the spinor case. The form factors are then evaluated in a « tail » approximation and substituted into the single photon exchange term for elastic e-d scattering. The resulting expression is very similar to the Jankus formula, but shows that the usual modificatione → e F1s should more correctly bee → eFchs(l — s/4md2-1. The bare form factors should also be multiplied by(1 — s/4md2)-1. Small angle scattering is re-analysed with the new formula; the changes are largely masked by the experimental uncertainties, but result in a small increase in the neutron form factor F1n.