In following hematopoetic disturbances after radiation most studies are centerd around the leucocytes and blood platetes system. Reports on the effect on erythrocytes system are few. However, the seemingly relatively unresponsive effect of radiation on erythrocytes can be attributed to the enormous number of peripheral red cells and its long lifespan of 120 days. In the bone marrow the young erythroblasts are more suseptable to the effects of radiation then either the leucocytic or blood platetes system. In order to observe these effects directly, intravenous globulin isotope ⁵⁹Fe test was found to be a good indieator of the radiation injury of the hematopoetic system. It is believed to be a reliable indicator of chronic and acute hematopoetic disturbances due to radiation.