  We have investigated the recently proposed self-consistent theory of
fluctuation - induced transport. In this framework the subsystem under study is
coupled to two independent baths at different temperatures. In this
non-equilibrium system one can extract energy at the expense of increased
entropy. This is a simple model of Maxwell's demon engine that extracts work
out of a non-equilibrium bath by rectifying internal fluctuations. We point out
the errors in the earlier results. We have obtained an analytical expression
for the fluctuation - induced transport current in a non-equilibrium state and
various cases of physical interest have been elucidated.
