A more ominous phenomenon is the fall in the birth-rate of most of the insular tribes of the Pacific, which in some cases has led to their total extinction. The causes of this fall have never been fully cleared up. If it is due to the introduction of diseases by Indo-European germ carriers, or the adoption of modern clothing, or the destruction of native standards of morality by the introduction of Asiatic religions, there is no cause for alarm concerning the future of the human race as a whole. But if the mere discouragement of the tribe when faced with new conditions can act directly upon the instinct of procreation, and affect, so to speak, the élan vital of the germ-plasm, then we are faced with the gravest danger to which the human race can be exposed.
For such an effect would be too insidious to be dealt with by public measures. It would be a psychological disease of the most fatal and virulent kind. It might affect the whole human race during some crisis in its fortunes, and might bring about its destruction by the failure of the sex instinct.
Although such a failure must always be a menacing possibility, it is a remote one, and at no time has it threatened the human race as a whole. Hunger and Love have kept our race going up to now, and, barring unforeseen developments, they will do so in sœcula sœculorum.
But there are other dangers. A new germ might be evolved which, like the gonococcus, might attack the germ plasm, and produce general sterility. This is one of the dangers that can be fought by hygienic and sanitary measures, and the wiles and intricacies of bacteriological novelties may be safely left to the ever-increasing resources of bacteriology itself.
Again, there is the danger of new “rays.” It is now a well-known fact that X-rays produce sterility when penetrating the human body in considerable strength or for any length of time. The effect can be guarded against by an armour of lead screens. X-rays are cut off by a thin sheet of lead. There are other rays, known as gamma-rays, which can penetrate several inches of lead. And higher up in the atmosphere, about seven miles up, another kind of radiation is found from which even a plate of lead five feet thick would be no protection. If the sun, entering an unknown part of space filled with denser matter, were to develop a form of radiation leading to a considerable increase in the penetrating atmospheric rays, the persistent action of these rays upon the human germ plasm might bring about the total destruction of the human race by reducing its birth-rate to zero. The effect might not even be discovered until it was too late to remedy it. And even if it were discovered in time, the action of the rays upon all life on the earth’s surface might have produced havoc enough to stop all food-supplies and produce universal starvation.
It is difficult to see how even the greatest resources of science could meet such an emergency as that. But, short of such a new danger, there is little doubt that the resources of humanity will be able to meet all conceivable situations which may threaten it with destruction.
In order to ensure the indefinite continuance of the human race on earth, it is necessary
(1) to maintain adequate food supplies and (2) to conserve the procreative impulse.
The latter condition might, indeed, be put first on the list.
These are the conditions of bare existence. Progress and happiness are, as they always have been, secondary considerations. Many minds have regarded one or both of them as unessential. Thus, it is not at all necessary to contemplate an increasing population of the globe. The leadership of the human race can much more effectively be maintained by educating individuals than by increasing their numbers. And as regards happiness, that can safely be left to take care of itself. All progress is progress towards greater happiness. Even mere existence can be a source of supreme happiness, as when a great danger has been successfully averted.