  High partial waves for $pp$ and $np$ elastic scattering are examined
critically from 210 to 800 MeV. Non-OPE contributions are compared with
predictions from theory. There are some discrepancies, but sufficient agreement
that values of the $\pi NN$ coupling constants $g_0^2$ for $\pi ^0$ exchange
and $g^2_{c}$ for charged $\pi $ exchange can be derived. Results are $g^2_0 =
13.91 \pm 0.13 \pm 0.07$ and $g^2_c
  = 13.69 \pm 0.15 \pm 0.24$, where the first error is statistical and the
second is an estimate of the likely systematic error, arising mostly from
uncertainties in the normalisation of total cross sections and
$d\sigma/d\Omega$.
