Not only has man made himself the only animal which constantly increases in numbers, but this increase, as Professor Lankester points out in another part of his lecture, already threatening certain difficulties, will be much more rapid than at present, assuming the birth-rate to remain where it is, when disease is controlled. It is within our power, as Pasteur declared long ago, to abolish all parasitic, infectious or epidemic disease. This must be and will be done—within a century, I have little doubt. The problem of the increase of human population will become more pressing than ever. Professor Lankester suggests that in one or five centuries the difficulty raised by our multiplication “would, if let alone, force itself upon a desperate humanity, brutalised by over-crowding and the struggle for food. A return to Nature's terrible selection of the fittest may, it is conceivable, be in this way in store for us. But it is more probable that humanity will submit to a restriction by the community in respect of the right to multiply.” The lecturer added that we must therefore perfect our knowledge of heredity in man, as to which “there is absolutely no provision in any civilised community, and no conception among the people or their leaders, that it is a matter which concerns anyone but farmers.”
The secret of multiplication.—Professor Lankester, however, omits to point out the astonishing paradox involved in the fact that—as I pointed out at the Royal Institution in 1907—man, the only ceaselessly multiplying animal, has the lowest birth-rate of any living creature.[19] From the purely arithmetical point of view, what does it mean? We may defer at present any deeper interpretation.
It means necessarily and obviously that the effective means of multiplication is not a high birth-rate but a low death-rate. It is a necessary inference from the paradox in question that the infant death-rate and the general death-rate in man are the lowest anywhere to be found. Producing fewer young he alone multiplies.[20] It follows that a smaller proportion of those young must die. Unless it is supposed by bishops and others, then, that a peculiar value attaches to the production of a baby shortly to be buried, the suggestion evidently is the same as that to which every humanitarian and social and patriotic impulse guides us, namely, the reduction of the death-rate and especially the infant mortality. This is the true way in which to insure the more rapid multiplication of man, if that be desired. I believe it is not to be desired, but in any case the reduction of the death-rate and especially of the infant mortality is a worthy and necessary end in itself, and need not inevitably lead to our undue multiplication provided that the birth-rate falls. Hence the eugenists and the Episcopal Bench may join hands so far as the reduction of the death-rate is concerned, and the only persons with whom a practical quarrel remains are those who—in effect—applaud the mother who boasts that she has buried twelve.
The facts of human multiplication.—Human population continues to increase notwithstanding any changes in the birth-rate. This fact remains true, as shown by the latest obtainable figures. It should be one of the dogmas never absent from the foreground of the statesman's mind. Apparently nothing, however, will induce us to take this little forethought. When we build a bridge across the Thames, we ignore it; when we widen a bridge we ignore it likewise. When we make a new street we ignore it; when we build railways and railway stations we ignore it—excusably, perhaps, in this case; when we build hospitals we ignore it: four times out of five there is no room for the addition of a single ward in time to come. We have not yet even learnt, as they are learning in America and Germany, how to acquire the outlying lands of cities for the public possession, so that they may be properly employed as the city grows. The man who builds himself a villa on the outskirts of a city, ignores it, and is staggered by it in ten years. The lover of nature and the country ignores it: “Just look at this,” he says, “this was in the country when first I knew it, look at these horrible rows of villas!” The only possible reply to such a person is simply, “Well, my dear sir, what do you propose? General infanticide?” Most important of all, this fact, that, to take the case of Great Britain, some half million babies are born every year in excess over the number of all who die at all ages, is forgotten by our statesmen—or rather by our politicians. It could, of course, not be forgotten by a statesman. Quite apart from remoter consequences, especially in relation to the wheat supply, this persistent multiplication—which one has actually heard denied on the ground that the birth-rate is falling—is of urgent moment to all of us.
In 1907 the Census Bureau of Washington published some figures on the mortality statistics of nations, a summary of which may be quoted: “In all parts of the civilised world both the birth-rates and the death-rates tend to decrease, and, as a rule, those countries having the lowest death-rates have also the lowest birth-rates. In Europe the lowest birth-rate is that of France, the highest those of Servia and Roumania. The lowest death-rates are in Sweden and Norway; the highest in Russia and Spain. The downward tendency of the birth- and death-rates is best shown by diagrams prepared by the French Government, and it is probable that the downward tendency is actually steeper than the diagrams show, because both births and deaths are more accurately registered than formerly.”
But these statements are by no means necessarily incompatible with steady increase of population, which, of course, increases so long as the birth-rate exceeds the death-rate. I quote a few figures from the Science Year Book of 1908:
In 1890 the total population of the world was estimated at 1,487,900,000.
| Aryan (Europe, Persia, India, etc.) | 545,000,000 |
| Mongolian (N. and E. Asia) | 630,000,000 |
| Semitic (N. Africa) | 65,000,000 |
| Negro (C. Africa) | 150,000,000 |
| Malay and Polynesian | 35,000,000 |
| American Indian | 15,000,000 |
The total figure now must be something like sixteen hundred millions at least.