  We exploit a recent lattice investigation (UKQCD) on the topological
structure of the (quenched) QCD vacuum, in order to gain information on crucial
building blocks of instanton perturbation theory. A central motivation is to
further constrain our previous predictions of instanton-induced hard scattering
processes. First, we address the generic problem of extracting quantitative
information from cooled lattice data. We find a new scaling variable,
interpreted as a "cooling radius", which allows to combine lattice data for a
whole range of lattice spacings and cooling sweeps. This variable strongly
helps to extract information on the uncooled distributions of interest. After
performing the continuum extrapolation of the instanton size and
instanton-anti-instanton distance distributions, we find striking agreement
with the theoretical predictions from instanton-perturbation theory, for
instanton sizes below 0.5 fm and distances above 0.5 fm, respectively. These
results imply first direct support for the validity of the known valley
interaction between instantons and anti-instantons.
