If we discuss the question how civilization will influence natural selection, we shall not do it with the hope of arriving at a firm answer. We shall do it rather in order to illustrate how doubtful all the arguments are which concern the interplay of two processes which cannot be measured in the same scale.
It is true that we can and do preserve the lives of children who, because of inherited weaknesses, would perish under natural conditions. It is true too that we do this for reasons and for feelings concerning the individual and we do it without regard to the consequences to the race. However, under our present condition of civilization a disease which can be corrected by administering chemicals or using the surgeon’s knife is no longer effectively a disease. In our present condition such a life can be as valuable to society and to the race as a life which does not have these superficial shortcomings. That we can and do preserve more life in this manner only emphasizes that under present conditions biological differences which used to be important no longer matter.
On the other hand, in social living many properties which used to be indifferent for a wild being have become of great significance. Ability to communicate and to get along with our fellows is not the only one, but is perhaps the most obvious one of such properties. The struggle for existence has become more gentle, and the chance of any individual to live on in his children is governed by new ways of behavior. Nevertheless the difference between the individual adapted to civilized living and the one who is not adapted is of great importance and will become of greater importance. It is likely that civilization will not eliminate evolution of the race. Rather it will direct it into new paths.
But the greatest change might be expected from an entirely different direction. We are going to understand in real detail the intricacies of human inheritance. Then we shall be faced with problems and shall find possibilities of an entirely new and different kind. The interest of a person in his children is not a superficial one. It is one of the most strong and lasting forces in biology, sociology and history. A clear understanding of the details of inheritance may bring about some grave difficulties because a new situation is never fitted easily into existing patterns of living. In the end more understanding may bring about improvements of a kind beside which all the worthwhile things that have been so far accomplished, might look unimportant.
The real importance of radioactivity for heredity does not lie in the fact that we may speed up the glacier by one inch in a millennium. The real importance of nuclear radiation is rather that it is helping us to understand the strange processes of life and the curious substances which connect one generation to the next.
CHAPTER XIV
The Cobalt Bomb
Nuclear explosions seem horrible for many reasons. They were presented to an unprepared world as a dramatic surprise—as the climax to the slaughter of the Second World War. Their power of destruction is fantastic. Before we had adjusted our thinking to atomic bombs, an even more potent tool of warfare—the hydrogen bomb—was invented. Worst of all: To the fear of destruction there was added the dread of the unknown. It is not surprising that discussion of nuclear weapons has not proceeded on a purely rational level.
To the nightmare of the atomic and hydrogen bombs has been added—not as a reality but as a further threat—the cobalt bomb. The idea of such a bomb is to intensify the most terrifying aspect of nuclear explosions: the radioactivity. This radioactivity could be used to poison the enemy. It could get out of hand and poison everyone.
Cobalt⁶⁰ is a radioactive isotope of the fairly common metal cobalt. It can be easily produced by absorbing slow neutrons in the natural and stable cobalt⁵⁹. It has a half-life of five years and it emits penetrating gamma rays. These properties make it useful in cancer therapy.
Many cancerous growths are more sensitive to radiation than healthy tissue. Therefore radiation can be used to reduce—sometimes even to destroy—dangerous tumors. The penetrating rays of cobalt⁶⁰ can reach the cancer even deep inside the human body. The lifetime of cobalt⁶⁰ is long enough so that this substance is easily installed in hospitals.