  We report on a recent investigation on the dynamics of light quarks, at
intermediate and low energy. By measuring some appropriate correlation
functions on the lattice, it is possible to probe the Dirac and flavor
structure of the non-perturbative quark-quark interaction and look directly for
signatures of the 't Hooft Lagrangian. Results obtained with chiral fermions
strongly support the instanton picture and the phenomenological parameters of
the Instanton Liquid Model
