In order to investigate the inhibitory effects of Co(++), Ni(++) and Zn(++) on oxydation of glucose by Sh. flexneri and Staphy. albus, the author made a comparison between the enzymatic properties of the organisms that were cultured on the media containing these metal ions and that of control. The following results were obtained. 1) The oxydative ability for pyruvate and its related substances was considerably lower in the organism grown on inhibitor contained media than in in the control; the accumulated products from glucose metabolism, such as pyruvate, were abundant on the organism tested compaired with control; therefore it could be supposed that the further oxydation of pyruvate was not taken place so successfully. 2) The mechanism of the inhibition on the oxydation were supposed to be the same way in either metal ions tested. 3) It could not succeed to demonstrate the occurence of any changes in the way of glucose oxydation and the hydrogen transfer system of tested organisms.