Washing of organisms by phosphate buffer results in the decrease of their respiration, and the addition of divalent metal ions such as Mg⁺⁺ , Fe⁺⁺ , Mn⁺⁺ restores the decrease. This study is performed to determine the mechanism of action of such metal ions by observing the influence of these ions on the metablism of metal ion deficient organisms; some strains of Sh. flexneri, Sh. dysenteri, S. typhi, Staphyl. albus, Staphyl. aureus, Staphyl. citreus, E. coli, Pseudomonus aeruginosa. (1) The respiration in which glucose or pyruvate are substrates can be accelerated by metal ions and moreover in the case of Sh. dysenteri 3, succinate is the substrate in which respiration is accelerated too. (2) The action of metal ions seemed to cause the reaction to perfect oxidation and in the case of Sh, dysenteri 3 succinate → fumarate reaction is accelerated too. (3) It is concluded that metal ions act on enzyme system concerning phosphorus metabolism coupled with oxidation and this action results in the acceleration of respiration.