A general expression has been obtained' for the evaluation of the successive stability constants of complex ions both in the higher and lower valence states from polarographic data. In four special cases, the general expression can be reduced to the results obtained by Lingane (1941), de Ford and Hume(1951),and Jachemirskii (1953). An expression is also provided for the evolution of the diffusion constants of individual complex ions from the measured diffusion current constants.