  Once density-dependent meson masses are introduced into the nuclear many-body
problem, conventional mechanisms for saturation no longer operate. We suggest
that a loop correction, essentially the introduction of the axial vector
coupling $g_A(\rho,k)$ as function of density $\rho$ and momentum $k$, can
bring about saturation, and present schematic calculations to illustrate this.
We find that a very small density-dependence in $g_A$ gives rise to a very
large saturating effect on nuclear matter. In fact, this new saturation
mechanism turns out to be more powerful than any of the conventional
mechanisms.
