Changes of bone marrow cell and peripheral blood cell counts in newborn mice

Differential bone marrow cell and peripheral blood cell counts in new-born mice from zero to twenty-one days of age were investigated. In the bone marrow, erythroblasts rapidly increased whereas granulocytic cells decreased with time. The G/E ratio was 6.7 on day zero and 0.5 on day four, and as the G/E ratio of adult mice is normally from 0.8 to 2.4, these values would be the highest and lowest respectively for the whole life span of a mouse. In the peripheral blood, MCV decreased each day, closely matching the changes in the Price-Jones curves. The results of erythrocyte area measurements indicate that the larger the erythrocyte area, the earlier in days of age it disappeared and the shorter its life span.