ABSTRACT
Ionizing radiations were first used in medicine for the diagnosis and treatment of some of the most alarming diseases such as tuberculosis or cancer. Many circumstances led to a fear of radiation which it is hard to combat. In an effort to attain some reasonable balance of emphasis we have examined some of the other risks to which mankind is exposed and some of the contributions which radiation and atomic power have made or might make in our society. The knowledge that evolution has taken place in a radiation field of even higher intensity than now existing may well argue that mechanisms of repair and deletion may exist of which we are unaware. Natural selection must, one would think, evoke mechanisms for the control of its own means of action and the means of controlling mutation rate must be an important part of evolutionary mechanism.
