established the existence of a systematic relationship between the values of log P in the range 1–5 and values for the partitioning of solvents in cytoplasmic membrane. When a solvent penetrates into a membrane, it disturbs the integrity of that membrane and, hence, its function leads to an uncontrolled proton and potassium ions efflux. This leakage causes a lowering in the proton-motive force and leads to an impairment in the energy conservation