  The differential cross section for the reaction $^{12}$C$(\gamma ,\pi ^{+}p)$
has been measured in the $\Delta$ resonance region at high recoil momenta of
the residual nuclear system. The data are analysed under the assumption that
the formation of $\pi^+p$ pairs may be interpreted as
$\gamma\Delta^{++}\to\pi^+p$ process, proceeding on the $\Delta^{++}$
constituent in a target nucleus. As a result, the estimation $N_\Delta=0.028\pm
0.008$ deltas per nucleon in $^{12}$C was obtained.
