In the study of changes in the production of blood cells and hemoglobin of the bone marrow in rabbits infected with various pyogenic bacteria, the author obtained' the following results: 1. In giving the intravenous daily injection of Streptococcus viridans (0.5mg/kg) to four groups of rabbits for consecutive days, one, four, seven and 14 times each respectively, taking daily blood counts of each group, and conducting bone-marrow tissue culture after respective injection, it has been found that peripheral leucocytes (especially pseudo-eosinophils) decrease in number immediately after the injection, but the number increases after 12 to 24 hours; and this process is repeated at each injection. Moreover, anemia, gradually progressing, becomes most pronounced around the seventh injection, and thereafter it turns to recover by degree. When the bone marrow tissue is cultured at the stage where leucocytes are on the increase; in the case of cover-slip method the relative growth rate increases, reaching the maximum after the seventh injection and tends to return to the normal level after the fourteenth injection, and the cell-density index remains at the normal level or is increased slightly, indicating an increase in the leucocyte series of the bone marrow. In the fluid medium cultures performed at the same time as mentioned above, the increasing rate of erythrocytes, reticulocytes, and hemoglobin of the bone marrow falls, and the degree of such a change more or less coincides with the changes in the anemic conditions of the peripheral blood. 2. When heat killed Streptococcus viridans (a daily dosage of 0.5mg/kg) is injected four consecutive days, such changes in blood and bone-marrow tissue cultures as mentioned above are slight; and when Streptococcus haemolyticus (0.5mg/kg), Staphylococcus aureus (0.5mg/kg) or Staphylococcus albus (1.0mg/kg) is injected four consecutive days, similar blood- and bone-marrow tissue culture findings can be obtained as in the case of four consecutive injections of living Streptococcus viridans, showing not any significant difference by strains of bacteria.
Thus the author obtained the findings in bone marrow that amply endorse the changes in the peripheral blood under pyogenic infection by bone-marrow tissue culture.