  We study topological properties of SU(3) gauge theory using improved cooling.
In the absence of fermions, we measure a topological susceptibility of $(182(8)
MeV)^4$ and an instanton size $\sim 0.6$ fm. In the presence of light staggered
fermions and across the chiral transition, the susceptibility drops in a manner
consistent with the quenched case, and the instanton size changes little. No
significant formation of bound instanton-antiinstanton pairs is observed, in
particular not along the Euclidean time direction for $T > T_c$.
