Review of the 2002 Annual Meeting of the Biological Stain Commission

Bacterial cells were stained in sequence, and at various pH's, by 22 different basic dyes. It was found that any dye could replace another already present in the bacterial cell. This replacement was shown to act according to mass action laws for reversible reactions, and hence was influenced by concentration of reagent and time of application. Since basic dyes are also known to react at carboxyl group sites, the phenomena of staining of bacterial cells by ordinary basic dyes must be a chemical adsorption exchange reaction.