By conducting bone-marrow tissue culture of hypoplastic anemia in fluid medium, the method modified by Kumeda and Iwasaki of our department, the author calculated the erythrocyte count and determined the change in the hemoglobin content: and comparing these results with those in normal persons, obtained the following results: 1. In the bone-marrow tissue culture of hypoplastic anemia in the fluid medium, the erythrocyte count and hemoglobin content after three hours' culture already showed values lower than those before the culture; and thereafter tended to decrease gradually. In the case case of the control, normal persons, each of these values after three hours' culture was higher than that before culture, showing a gradual increase thereafter. 2. Looking hypoplastic anemia according to the types of this disease, the degree of decrease in the erythrocyte count was least in Type I, followed by Types II-IV, and it was highest in Type V. Similarly the decrease in the hemoglobin content was least in Type I, followed by Types II-IV and it was highest in Type V.