Part I O(2) Uptake of the Fresh Cells Using Candida albicans, C. krusei, C. parakrusei and C. tropicalis, the author studied the O(2) uptakes of the organisms at the expense of various carbon compounds or amino acids as substrate and the environmental factors to this. The following results were obtained. 1) The endogenous respiration of each strain was fairly high, and this respiration tended to decrease by the shaking of cell suspension without addition of substrates. Since prolonged shaking of the cell suspension may cause the inactivation of enzyme activity, the most advantage were given on the cell suspension that was previously shaken for 1-2 hrs. in order to study the enzymatic properties of the organisms. 2) Generally, the O(2) uptakes of Candida were high at the expense of glucose, acetate and citrte. Besides this, the O(2) uptake of C. albicans was also high at the expense of lactate and pyruvate. 3) As a whole, it could say that the greater enzyme activity was found on the cells of shorter cultivation compared with that of longer cultivation. And the organism cultured by shaking method showed more accelerated O(2) uptake at the oxidation of lactate, pyruvate and acetate than the cultured in still-standing method, this fact possibly implied that the metabolism of the former organism was carried out very satisfactory. Part II Properties of Freezing-dried Cell Preparation andFraction of Ground Fresh Cell As in the previous report, part I, using 4 strains of Candida, C. albicans, C. krusei, C. krusei, C. parakrusei and C. tropicalis, the author prepared the freezing-dried cell preparation and the fractions of ground fresh cells, studied O(2) uptake, catalase activity and action of inhibitors to these. The results obtained were following. 1) The freezing-dried cells showed an catalase activity in a same extent as the living cells, and a large amount of O(2) uptake with glucose, lactate, citrate and succinate; while a marked decrease of O(2) uptakes were found with pyruvate and acetate. 2) The supernatant fraction obtained from ground fresh cell at 40,000 rpm showed greater catalase activity, and greater oxidative capacity for pyruvate, acetate and citrate, and also accelerated endogenous respiration. On the other hand, the sediment separated by centrifugation at 40,000 rpm had no catalase activity; but revealed specifically much greater oxidative capacity for lactate and succinate. 3) It was confirmed that the action of inhibiter was more effective on the freezing-dried cells and the cell free extract than on the intact living cells; by an addition of KCN the O(2) upteak was not affected on the living cells, but was serionsly inhibited on the freezing-dried cells and the cell free extract.