  We investigate the possibility of identifying an explicit pionic component of
the nucleon through measurements of polarized $\Delta^{++}$ baryon fragments
produced in deep-inelastic leptoproduction off polarized protons, which may
help to identify the physical mechanism responsible for the breaking of the
Gottfried sum rule. The pion-exchange model predicts highly correlated
polarizations of the $\Delta^{++}$ and target proton, in marked contrast with
the competing diquark fragmentation process. Measurement of asymmetries in
polarized $\Lambda$ production may also reveal the presence of a kaon cloud in
the nucleon.
