  The recent discovery that some of the coefficients of the viscosity tensor
are negative is shown to invalidate the hydrodynamic approach to the vortex
liquid phase of a type-II superconductor. A satisfactory theory requires
retention of all the spatial gradients of the velocities or electric fields and
not just the first derivatives, as assumed in a hydrodynamic theory. We
illustrate such a procedure by using time-dependent Ginzburg-Landau theory to
determine the electric field distribution near a single ``twin-plane boundary"
due to a current passing through the boundary.
