  We compare the chemical potential associated with the onset of non-zero
baryon number density on $6^4$ and $8^4$ lattices at $\beta=5.1$ and ma=0.01.
We provide evidence for $Z(3)$ tunnelling. We determine a critical chemical
potential of $\mu a \simeq 0.1$ which is unexpectedly low. We also determine
the dependence of the onset of the observed phase transition on the quark mass.
The physically misleading result of the quenched theory is shown to persist
despite the inclusion of the complex fermion determinant.
