  It has long been expected that the pionic modes show some collective
phenomena such as the pion condensation in the high density nuclear matter and
its precursor phenomena in the ordinary nuclei. Here we show an evidence of the
precursor observed in the isovector spin longitudinal cross sections ID_q of
the quasielastic 12C, 40Ca (\vec{p}, \vec{n}) reactions at T_p = 346 and 494MeV
with the momentum transfer q = 1.7fm-1. Another aim of this report is to
evaluate the Landau-Migdal parameters g'_{NN}, g'_{N\Delta} and
g'_{\Delta\Delta} at the large momentum region from the above reactions. We
obtained g'_{NN} \approx 0.6-0.7, g'_{N\Delta} \approx 0.3-0.4. The results are
consistent with those at the small momentum region, which are obtained from the
Gamov-Teller strength distribution.
