  We study lepton flavour-violating interactions which could result in the
$\tau$-lepton production in the $\nu_{\mu}N$ scattering or in $\mu \to \tau$
conversion on nucleons at high energies. Phenomenological bounds on the
strength of $\bar{\tau}\nu_{\mu}\bar{q}q^{'}$ interactions are extracted from
the combined result of the NOMAD and CHORUS experiments on searching for
$\nu_{\mu} - \nu_{\tau}$ oscillations. Some of these bounds supersede limits
from rare decays. We also propose a ``missing energy'' type experiment
searching for $\mu - \tau$ conversion on nucleons. The experiment can be
performed at a present accelerator or at a future neutrino factory.
