This paper emphasizes that non-linear rotational or diamagnetic
susceptibility is characteristic of Bose fluids above their superfluid Tcs, and
for sufficiently slow rotation or weak B-fields amounts to an incompressible
response to vorticity. The cause is a missing term in the conventionally
accepted model Hamiltonian for quantized vortices in the Bose fluid. The
resulting susceptibility can account for recent observations of Chan et al on
solid He, and Ong et al on cuprate superconductors