  In transformations between nonequilibrium stationary states, entropy might be
a not well defined concept. It might be analogous to the ``heat content'' in
transformations in equilibrium which is not well defined either, if they are
not isochoric ({\it i.e.} do involve mechanical work). Hence we conjecture that
un a nonequilbrium stationary state the entropy is just a quantity that can be
transferred or created, like heat in equilibrium, but has no physical meaning
as ``entropy content'' as a property of the system.
