  The cross section of the photonuclear reaction in the nucleon-resonance
region is calculated to search the resonance-nucleon scattering amplitude in
the nucleus. It is assumed that the resonance $R$ is produced and decayed in
the elementary photon-nucleon $(\gamma N)$ reaction in the nucleus as $\gamma N
\to R \to \gamma N$. The resonance interacts with the nucleons while
propagating through the nucleus. Therefore, the calculated photonuclear
reaction cross section is compared with the data to extract the
resonance-nucleon scattering parameters in the nucleus.
