. : Ga. In Table 2 the physical, biological, and effective half-lives of the main elements which are supposed to deposit in the human body are given together with the organs in which they tend to deposit. As is evident from this, these elements have a tendency to deposit in the bone, thyroid, kidney and liver. which have not been detected yet. in these organs. There may be some rare earths If they exist, they will also deposit In the animal experiments, the Bikini ash was given to the animals with the food and also by the hypodermic injection and then their autoradiograph was taken. The result is the same as that of Table 2. Especially, the deposit is found to be the largest in the bone. This is very important in connection with the problem of prognosis of the patients, The result up to March 26 of quantitative analysis making use of the radioactivity of these elements is shown in Table 3. (Kimra Lab.) To our slight relief in this unfortunate accident, mre than 50% of the radioectivity is found in the rare earths while the amount of Sr90 is only of the order of 0.02%. The radioactive elements are absorbed in various ways through the digestive organ, respiratory organ, skin, etc. The rate of absorption of course depends on the elements and the chemical compounds which they form. 3. Clinical Problems: Injury of patients of the Bikini accident has been caused by the radiation of the fallout in contrast to the atomic bomb injury at Hiroshima and Negasaki. In the former, the injury is caused either by the irradiation of 6- andX - rays of fission products located outside or on the surface of the body or by the irradiation of special organs such as the bone, thyroid, kidney, and liver in which the fission products are deposited by means of absorption through the respiratory organ, digestive organ, skin, etc. In the latter, the main cause of the (radiation) injury is the exposure to the initial nuclear radiation though there may be some effects of the induced radiation from inside and outside of the body. Thus the characteristic danger of the Bikini zsh lies in the fact that the fission products deposit in such organs as the bone, thyroid, kidney, and liver; irradiate them, and moreover, are difficult to take out of these organs. To understand better the effect of radiation on the livingbody, we shall first see what reaction will happen:-when the energy of the f - or ¥- ray is absorbed by a cell, which is a unit of the life, In general the living body conteins a lot of water which will be ionized by the radiation yielding the free radicals like H* and OH™ or the harmful molecules like HpQ.. If this happens, the function of cells is damaged and such a biological change follows as the destruction of -~-2koiaf Dacroy Deper’yont us N, “ Ta eee ee FHGLG vee oT ae - i ee uy