Using the strains of Sh. flexneri and Staphy. albus as the test organism, the author studied the O(2) uptake of the resting cells cultured on nutrient agar media for 20 hours, the inhibition caused by Co(++), Ni(++) or Zn(++) on oxydation of glucose or pyruvate in the organisms and the recovering effect of Mg(++), Fe(++), Mn(++) or thionine against the inhibition. The following results were obtained. 1) The O(2) uptake of Sh. flexneri was, of course varying in degree, considerably supprersed at the concentration of 10(-4)M of metal ions, Co(++), Ni(++) or Zn(++), regardless the sort of metal. Especially it was serious in the case of oxydation of pyruvate. 2) Concerning Staphy. albus, it was observed only slight inhibition of glucose, but serious inhibition was found in the case of pyruvate. Hence the difference on the inhibition, preeumably, regarded to be based on different pathway of glucose metabolism besides the differnce in the permeability of the surface of bacteria for ions. 3) It could be postulated that the inhibition of Co(++), Ni(++) or Zu(++) on oxydation of glucose were based on a block of the step on the oxydation of pyruvate, since these metal ions could compete with Ng(++), Fe(++) or Mn(++) that were necessary for such enzyme action.