In any event the number of additional cases of leukemia and bone cancer due to the fallout radiation is certainly too small to be noticed against the natural incidence of these disorders. In the next thirty years about 6,000,000 people throughout the world will die from leukemia and bone cancer. From past tests, which have involved the explosion of about fifty megatons of fission energy, the possibility exists that another 50 × 200, i.e., 10,000 cases may occur. Statistical methods are not able to find the difference between 6,000,000 and 6,010,000. There is no way to differentiate between the fallout-induced cases of leukemia and bone cancer, and those which occur naturally. The possible shortening of ten thousand lives may seem rather ominous. But mere figures can be misleading. A better way to appreciate the danger from fallout is to compare it with other more familiar dangers. Such a comparison can be made with the natural background of cosmic rays and radioactivity in the earth and in our own bodies. We are constantly and inescapably exposed to this radiation. Our ancestors have been exposed to it. The human race has evolved in such a radioactive environment. Moreover, the biological effects from different kinds of radiation can be compared in a meaningful way in terms of roentgens. Therefore the danger from Sr⁹⁰ is not unknown in every respect. In some ways it is very well-known because we and all living beings have spent our days in a similarly dangerous surrounding. We live on an earth which has radioactivity in its rocks, which carries a similar activity in its waters, and which is exposed from all sides, to a rain of particles which produce effects identical with the effects of radioactive materials. Not all radiations which have the same intensity (the same number of roentgens) have precisely the same effect. The damage produced also depends somewhat on the spacing of the ionized and disrupted molecules. The cosmic rays and the Sr⁹⁰, however, are quite similar even in this respect.