Complete blood counting on 131 A-bombed survivors in Fukuoka and Saga Prefectures and bone marrow function test by the use of cobalt-chlorophyllin on 40 survivors were carried out in 1961.
The hematological examination revealed a slight, insignificant decrease in hemoglobin, red blood cells, thrombocytes and leukocytes, and a significant increase in color index compared with normal values. Local analysis revealed that the average values of hemoglobin, red blood cells, thrombocytes, leukocytes and neutrophils of survivors in Tagawa District (Fukuoka) were lower than the normal values and those in Northern Kyushu District, and that of color index was higher than normal values. These changes were found statistically significant and counted to be due to the poor economic conditions.
Study on bone marrow function test revealed that there were 21 hypofunctional cases (52.5%) and 19 normal cases (47.5%). The average values showed significant decreases compared with normal values. Regarding its relation to other factors, the results of the function test correlate, to some degree, with the blood picture, but neither to the bone marrow picture nor to the hypocentric distance at which the survivor was exposed. The reasons for these contradictory results were considered in some detail.

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The abundance of rare earth elements in marine organisms has been determined by use of activation analysis. The lanthanum contents in bone, scales, shell, gills and dorsal fins of fish were found to be 10^-5-10^-7 g/g of wet weight ; the internal organs such as the stomach, heart, intestines, etc., were 10^-8 g/g (wet) ; and the muscle showed the smallest value, 10^-9 g/g (wet).
Other rare earth elements also, i. e., praseodymium, samarium, europium, dyprosium and holmium were found in marine organisms.
The general trend of most of the rare earth elements in marine organisms is toward concentrating in the bone structure.

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The influence on 5-Hydroxytryptamine (5-HT) contents of small intestine of X-irradiation (500-2, 000r whole-body) was studied in rats, mice, guinea-pigs and rabbits. In order to examine the relationship between effect on 5--HT contents and intestinal injury by radiation, mean survival time and incidences of diarrhea were also observed in each species following irradiation.
5-HT contents of small intestine were remarkably reduced by exposure. The depressed level of 5-HT continued 48 hrs. There were great differences in normal contents of 5-HT and reduction rate after exposure among these species. It was found that the species which have high 5-HT contents and large reduction rate after exposure were sensitive to radiation.
The radiation sensitivity of intestine seemed to be closely related with its endogenous 5-HT. Its possible relationship was discussed.

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Dependence of the recent increase in leukaemia on the levels of environmental radiation has been analysed. Main sources of information were (a) correlation of levels of terrestrial radiation and leukaemia mortality in some districts in Japan, (b) correlation of an increase in diagnostic X-ray procedures and leukaemia mortality in general population, and (c) interrelationship of the number of radiographers and their leukaemia mortality. Neither of them could give clear evidence that leukaemia mortality increased with an increase in radiation doses received by population at large. It seems reasonable to believe that environmental radiation, natural or man-made, though not to be neglected, play a subordinate role in the production of spontaneous leukaemia.

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To evaluate hazards of environmental contamination due to fission products from nuclear weapon test explosions, determination of body burden of the radionuclides taken in human body is essential. Because urine analysis is one of the practical methods to estimate body burden, Cs-137 concentration in human urine has been surveyed in Osaka and Ishikawa Prefectures since the fall of 1959. From the results of analyses, time variation of Cs-137 concentration and difference between two sampling sites were discussed with respect to the fallout rate. Cs-137 body burden was estimated from the analytical results by assuming the exponential equation for continuous exposure : In November 1959 the values were 8.4 mμc in Ishikawa and 6.0 mμc in Osaka respectively. And they decreased to 3 mμc in October 1961 in both areas. These values were consistent with the results obtained by other methods. Cs-137 gonad dose could be calculated with these values assuming uniform distribution of Cs-137 in a human body. Gonad dose rate due to internally deposited Cs-137 at present is about 0.7 mrad/y, and gonad dose up to the present is in the range of 5 to 8 mrad.

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Studies on the extirpated spleen showed that the increase in the amount of 0.14 M NaCl soluble DNA was independent on the conditions of irradiation but dependent on those of incubation.

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