  The spontaneous breakdown of the chiral symmetry of the QCD Lagrangian
ensures that $\pi\pi$ interactions are weak at low energies. How weak depends
on the nature of explicit symmetry breaking. Measurements of $K_{e4}$ decays at
DA$\Phi$NE will provide a unique insight into this mechanism and test whether
the $q{\overline q}$--condensate is large or small.
