  A quantum-mechanical prescription of static Einstein field equation is
proposed in order to construct the matter-metric eigen-states in the interior
of a static Schwarzschild black hole where the signature of space-time is
chosen as (--++). The spectrum of the quantum states is identified to be the
integral multiples of the surface gravity. A statistical explanation of black
hole entropy is given and a quantisation rule for the masses of Schwarzschild
black holes is proposed.
