  The dc conductance of normal-superconducting hybrid structures is discussed.
It is shown that since the Bogoliubov-DeGennes (BDG) equation does not conserve
charge, its application to create a Landauer-type approach for the conductance
of the NSN system is problematic. We `mend' this deficiency by calculating the
conductance from the Kubo formula for a ring configuration (for this geometry
the solutions of the BDG equation conserve charge). We show that the presence
of a superconductor segment within an otherwise normal metal may {\em reduce}
the overall conductance of the composite structure. This reduction enhances the
tendency of the NS composite to become insulating.
