[Ion-exchanging ratio and membrane potential in the bacterium S. faecalis]

The membrane potentials (delta psi) in S. faecalis equal to -140 mV were measured by means of TPP+-electrodes. The values of delta psi remain constant under temperature variation from 37 degrees to 18 degrees C. The ion-exchanging ratio during glycolysis was 2H+: Lac-: K+ where 2H+ and Lac- are liberated from the cell. It is not excluded that an electrogenic pump exchanging 2H+ by K+ operates in the membrane of S. faecalis.