© FICIAL USE ONLY - but at a lower level. 3 - /The neutron dose contribution at Nagasaki was smaller than at Hiroshima./ Lf an RBE dose in REM, using an RBE value of 5 is inserted instead of Total Dose (neutrons plus gamma radiation in rads) the Hiroshima and Nagasaki leukemia curves come very much closer together. In both cities, however, the response then becomes distinctly non-linear with pronounced concavity. 13. In Hiroshima the curve of mortality from cancer excluding leukemia versus total dose is nearly linear whereas in Nagasaki there is an enormous dip in the 100-199 rad range and the response at the highest doses is much smaller than in Hiroshima. 14. In terms of the RBE dose, the curves for mortality from cancer excluding leukemia for the two cities are not brought together as well at the highest dose levels as they were in the case of leukemia. It appears that an RBF of 6 or even 7 might be required to bring the two cities into agreement. At the lower dose levels agreement remains poor, since no amount of numeric manipulation will compensate for the deficit of cases in Nagasaki in the 100-199 rad (largely gamma rays) range. Further, when an RBE of 5 is used, the Hiroshima regression of mortality on dose, which is very nearly linear using Total Dose, becomes concave using the RBE dose. 15. As time has passed, there has been a shift in the excess mortality in the high dose survivors from leukemia to other cancer. In 1950-54, the excess leukemia deaths were about twice as numerous as those from all other cancer; ty 1965-70, the excess from other cancer has come to be three times that from leukemia. OFFICIAL USE ONLY