1? Ocean in 1954. Fourteen of them were examined under hospitalization, and the other four were treated as outpatients. At first we planned to examine all the exposed persons (twenty-two in total), however, mainly for reasons of their own, we could not include four of them in the 1904 survey. In general, these persons had been in goud health during the past years. Although several diseases occurred in some of them, there was no definite reason to relate the radiation exposure to such diseases. Since most of them got children after being discharged from hospitals, it would seem evident that permanent sterility did not occur in them. The routine physical examinations of 1964 revedaled that liver was palpable in ten cases. However, it was not cirrhotic, and did not seem to be related to liver disturbances. The routine physical examination had no observation to be relatable to the radiation exposure. Residual beta burns of the skin were noted in 13 people of the 18 examined. The burns were observed in wrists, external ears, abdominal walls, foot and leg. Most remarkable ones were those Skin biopsies of the abdominal walls were performed in six cases. Histological diagnosis as well as macroscopic exumination of these lesions indicated no malignant change. In one case that showed complete epilation at the time of the accident, a small alopecic area was still noted in the scalp. Ophthalmological studies revealed lens opacities in G6 cases, in which 2 cases showed opacities of posterior capsules. However, these changes had not characteristic features described about progressed cataracts of atomic bomb survivors in Hiroshima, although lens opacities of 2 cases were found in posterior. Further ophthalmological survey should be needed. Haematological survey showed that the results of peripheral blood examinations were almost seen in abdominal walls. normal, although neutropenia, lymphopenia, eo- sinophilia and slight basophilias were observed in one or two cases respectively. N. AP-ase-score decreased in one case. Bone marrow examinations revealed slight increase of myeloblasts and M;L ratio in Cases T-3 and K-12 respectively. “ Mitotically Connected Abnormalities ” were found in a few cases. In view of these findings, it could be indicated that there is some residual effect of radiation exposure on haematopoiesis on these persons. Chromosome observations of peripheral leucocytes were made in 13 cases. The average rate of chromosome aberrations was much higher than that in the normal. The frequency of aneuploid cells was higher, and chromosome-type abnormalities such as dicentric chromosomes and monocentric abnormal chromosomes were frequently observed. Cells with dicentric chromosomes occurred in 7 cases, and those with monocentric abnormal chromosomes werepresent in all of the cases. To trace the fate of such cells with chromosome abnormalities persisting in them seems to be necessary in the succeeding unnual investigations. There were some abnormal findings in different laboratory studies. However, it was not proved that radiation exposure was related to these results. Whole body counting and determination of urinary excretion of ‘Cs and *’Sr were carried out. No significant increase of '’Cs or “Sr was found on the exposed persons by the examinations. In general, the results of 1964 medical survey on Japanese fishermen did not indicate clinically significant late effects of the fall-out exposure in 1954. However, it seems to be very important as well as necessary to conduct further medical survey to detect the significance of subtle changes such as observed in haematological, chromosomal or ophthalmological examinations.