Page:Popular Science Monthly Volume 36.djvu/182

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IF any species or race desires a continued existence, then above all things it is necessary that that species or race should go on reproducing itself.

This, I am aware, is an obvious platitude; but I think it was John Stuart Mill who once said there were such things in the world as luminous platitudes. Some truths are so often taken for granted in silence, that we are in danger at times of quite losing sight of them. And as some good friends of mine have lately been accusing me of "barren paradoxes," I am anxious in this paper to avoid all appearance of paradox, barren or fertile, and to confine myself strictly to the merest truisms. Though the truisms, to be sure, are of a particular sort too much overlooked in controversy nowadays by a certain type of modern lady writers.

Let us look then briefly at the needful conditions under which alone the human race can go on reproducing itself.

If every woman married, and every woman had four children, population would remain just stationary. Or rather, if every marriageable adult man and woman in a given community were to marry, and if every marriage proved fertile, on the average, to the extent of four children, then, under favorable circumstances, that community, I take it, would just keep up its numbers, neither increasing nor decreasing from generation to generation. If less than all the adult men and women married, or if the marriages proved fertile on the average to a less degree than four children apiece, then that community would grow smaller and smaller. In order that the community may keep up to its normal level, therefore, either all adults must marry and produce to this extent, or else, fewer marrying, those few must have families exceeding on the average four children, in exact proportion to the rate of abstention. And if the community is to increase (which on Darwinian principles I believe to be a condition precedent of national health and vigor), then either all adults must marry and produce more than four children apiece, or else, fewer marrying, those few must produce as many more as will compensate for the abstention of the remainder and form a small surplus in each generation.

In Britain, at the present day, I believe I am right in deducing (after Mr. F. Galton) that an average of about six children per marriage (not per head of female inhabitants) is necessary in order to keep the population just stationary. And the actual number of children per marriage is a little in excess of even that high