lesions including epilation were observed on parts of the body not covered by clothing and on the navel region where radioactive dusts from neck were deposited. Histologically, these skins were similar to ordinary radiodermatitis. Remarkable epilation was observed in 20 patients. Two patients who did not wear hats at the time of the accident revealed complete epilational necrosis. Microscopically, coagulation necrosis and cell infiltration in the necrotic scalp was observed at ahout the 4th week. These skin lesions recovered gradually. Thin and delicate hairs began to grow again at the beginning of May, and in 2-3 months they grew back almost completely. But, T-2 and T-7 have alopecia even now. In some persons, capillary dilatation, depigmentation and pigmentation of skin arestill observed in the navel region. For the skin lesions every possible treatment was applied. For decontamination, mechanical washings with Na-EDT.A\ or warm water were done. The hair of head. axilla and pubes was shaved off. The nails were cut off. In one and half months superficial contamination was almost removed. The distribution of surface radioactivity and skin lesions is shown in Fig, 2.'” Total number of leucocytes decreased gradually, showing minimum count at about 4-8 wecks after the exposure. Five cases revealed a count of less than 2,000;/mm/’, thirteen less than 3,000, and five less than 4,000. In one case, the leucocyte level depressed to 800. A correlation was found between these minimum count and the doses of individual external irradiation. Neutrophil level also depressed. Between the 4th-8th weeks all of the cases got minimum values, which were proportional to the dose of radiation received (Fig. 3). In most cases a shift to the left of the nucleus was observed. Lymphopenia was noted between the 2nd-8th weeks in all cases. Leucocyte count began to increase since 8th week, At that time, metamyelocytes and myelocytes appeared in peripheral blood of some cases. In most cases eosinophilia and in some cases monocytosis were remarkable, especially with the indication of recovery. Eosinophilia continued in some cases for several years without proof of parasite. Neutrophil and lymphocyte levels recovered gradually. However, cumulative distribution curve of total leucocyte count at the 6th year was still slightly displaced to the left of normal Japanese, and in several cases, number of lym- Radicectivs Contamination phocytes was below 2,000/mm‘. Motility and phagocytosis of neutrophils depressed remarkably. Although they recovered gradually, after one year these functions in some cases were still lower than in normal persons. Erythrocytes At the time of hospitalization, a few patients were slightly anaemic (RBC 3,000,000/mm’). No reticulocyte was observed in them at the critical stage. The cumulative percentage curves changed as in Fig. 4. Colour index was higher than 1.0. The PriceJone’s curves of erythrocytes diameter were cn" ht Marked Moderate Fig. 2. MA, e Sight Uicer . e ee, + Sm Erosion Erytheme Epilaiion Distribution of Radiodermatitis!™ Tee eee 3. Haematological Observations Leucocytes displaced to the right of normal one at first, and returned to almost normal after one year. These changes corresponded to changes of erythroblasts diameter in bone marrow. oe eee eee These signs reached the peak in about the 3rd4th week and subsided gradually. These skin