  We present the results for the electric dipole amplitude for $\gamma N \to
\pi^0 N$ at threshold at the $O(p^2)$ level in SU$_f$(3) chiral perturbation
theory. We find that the SU$_f$(3) results differ only slightly from the
SU$_f$(2) results. At the $O(p^3)$ level one encounters new, unknown
counterterms to fix which one is likely to need the threshold photoproduction
data themselves, thus losing predictive power. We suggest, instead, that the
{\it difference} between the proton and neutron $\pi^0$ photoproduction
amplitudes may provide a test of the convergence properties of the $\chi$PT in
the present context. We urge that the neutron's electric dipole amplitude be
measured.
