The off-shell relationship between three-form field strengths and massless scalar fields is re-investigated, with particular attention paid to the boundary conditions in the path integral. The two theories are shown to be not completely equivalent, in agreement with earlier work. It is shown, in particular, that eigenstates of the “magnetic” part, Hijk, of the three-form field dualize to eigenstates of the canonical momentum, adot, of the scalar field. This correspondence is just what is required for the consistency of the dualization of the Giddings-Strominger wormhole to scalar field theory.