  We have measured the hadron spectrum in lattice QCD, using staggered
fermions, for 0 (the quenched approximation), 2 and 4 light degenerate
dynamical quarks. In addition to earlier results involving extrapolations in
valence quark masses for fixed dynamical mass, we also report results where we
extrapolate in the dynamical mass for 4 flavors. We see a marked difference in
the hadron spectrum for 2 and 4 flavors; the hadron spectrum is nearly parity
doubled for 4 flavors, indicating smaller effects of chiral symmetry breaking.
This pronounced effect in the hadron spectrum cannot be removed by a simple
change in scale as the number of light quark flavors is changed. Further
simulations at larger volume are needed to rule out finite volume effects.
