from the elements deposited in the body (especially in the bone) is small compared to the external radiation, But it may give a considerable amount of injury during the long period since it will continuously irradiate the important organ, namely the marrow. It is therefore necessary to observe carefully the clinical development in the future. For this purpose, it is important to measure and analyze the quantity of radioactivity in the urine, The study is now being proceeded from this viewpoint. In order to discharge the fission products deposited in the bones, EDTA(Ethylene diamine tetra acetic acid) can be used which however is not very efficient. It is reported that in an animal experiment about 20% of the substmces were discharged when EDTA-Na and EDTA-Ca were applied alternatively in an early stage of deposit. In our case, too, it may be possible, using EDTA, to discharge the fission products several times faster than otherwise. Since EDTA-Na, being poisonous, cannot be used to the human body, we are now trying to use EDTA-Ca. lh. About the Hygienics of the Environment and the Food: ERSTE LE op eeed itcien’s Ce frrmge (i) The Boat as the Living Place — As is discussed in the section” BS of the physical properties of the ashes, the half-life of the fission products on the FPukuryu Maru was changing from time to time. t was about 8 days at March 17 and 20 days at April 22, By this time, the intensity also decreased to about 20% of that of March 17. On April 22, the intensity of radiation in the boat ranged from 2 mr/hr to 20 or/hr. Tt mey not be very long before the intensity becomes less than the permissible dose 1.8 ur/hr. As is seen from Table 5, the measured intensity for f- rey 2elcne and the total intensity of both P- and J - reys are not very different. This may be understood the result of the distance between the measuring instruments and tne€~ ray sources, the absorption of considerable amount of f - rays by the wooden parts of the boat into which the radioactive substance soaxed, and the penetration of extra X- rays from remote scurces through the ceilings and the walls. The recietion has an effect on the human body through the ionizai 2 C4 so that the oe amount of injury should be meésured ty the miliroemicentetie It is not appropriate to use the Gi -counter. from one to the other is not simple either. The conversion of results There are mamy boats besides the FPulcryu Meru cn which the asn fell when they- were making voage several hunared rales off Bikini. The count of radicactivity on these boats varies fren Irindreés to ten-thnevssnds by the Gi-counter. But the intensity is at most 3 mr/nr when rmezsured at @ Gistance of 5 cm by the niliroentgenceter. Since the intensity at 50 cn is only one-hundredth of the enount et 5 cn, it may heve herdly ery effect on the hucan body. The emount cf redioactivity on these bozts is thereHow fore very szell end trivial comared to the case of the Furaryu Meru. ever, ifthe redicactivity is present at all, it may heve 2 chance of geiting into the body through the south, skin or lung. Of courses, better now tc be exposed to the radiation, nowéver a bit itis. I it