The Pfeiffer effect was studied in systems containing cinchonine hydrochloride and trisoxalatometallate(II1) complexes of Al, Fe, Cr, Co, and Ir. The Pfeiffer rotatory dispersion curves of the Cr and Co complexes show Cotton effects analogous to that observed in the optical rotatory dispersion (0.r.d.) curves of the respective complexes. The source of the Pfeiffer effect in all these systems is attributed either to an association between the complex ion and the optically active species in solution alone, as in the case of the Ir(lI1) complex, or to a combination of this association and an "equilibrium shift" between the two enantiomers in solution in favor of one of them, as in the case of the other complexes under investigation.