Mutation Rate

At present the effect of radioactivity in the body which is regarded as most serious is its effect on the mutation rate. It is thought that in this only small increases in radioactivity may produce large results over a period and so we must be immediately concerned. A mutant is an offspring of an animal which has characteristics not normal in the species to which its parents belong. It is thought to occur when certain special parts of those cells most directly concerned in reproduction are damaged. Experimentally we find that radiations produce mutations in plants and animals. Only in very rare cases can a mutation be regarded as an improvement. In nearly all cases the mutant is definitely defective and inferior to its parents.

Exactly how much cancer and how many mutations are caused by the radiation which the body receives from natural sources of radioactivity and cosmic rays is uncertain. Biochemical irregularities and other factors may also cause cell damage. [unclear: Experimentally] we can obtain a measure of the amount of radiation required to give twice the natural mutation rate in insects, mice, etc. And we can roughly say that if humans are subjected to similar doses there will be more genetic mutants born than at present. Perhaps many more as man is a more complex organism.

The explosion of atomic bombs has increased the amount of radioactivity in the world around us. So far the test explosions have only produced an increase which is small compared to natural radio-activity (radium in the earth, cosmic rays etc.). But already there are indications that special processes which [unclear: are] not well understood are causing localised danger from strontium-90. There is probably a greater danger in the increasing use [unclear: of] radioactive isotopes and X-rays. However, these are carefully controlled by legislation in most countries.

A nuclear war in which many atomic weapons were used would have an aftermath in which the world would be more radioactive than at present and the whole of humanity would be exposed to the consequences of this. I hope every one who has control over modern nuclear weapons views this with the same horror, as I do.

There is almost as great a problem in the increasing use of nuclear power. If all the world's power is produced by reactors collossal quantities of radioactivo material will be produced each year. Their disposal will be a serious problem. Also, more and more of the population, will be exposed to increased radiation while they attend our power plants.

The hydrogen bomb obtains most of its power from a different nuclear reaction from that of fission, in it there is fusion of light elements to make heavier ones, in this reaction very little dangerous radioactive material is produced, if a hydrogen bomb is exploded well clear of the ground it should produce no more radioactivity than an ordinary atomic bomb in spite of its far greater power.