nalism.

But though we widen our agricultural base, our population unless its
rate of progress is checked, will eventually, and perhaps soon,
overtake any extension.[16] Though we increase agricultural knowledge
and substitute mechanical for animal power and gasoline for hay, the
law of diminishing returns will remain. Ten men cannot secure as large
a per capita product from a given area as five, or twenty as large as
ten. But if our population were to maintain its present geometrical
increase we should have 200,000,000 inhabitants in 1953 and, to assume
the almost impossible, 400,000,000 in 1990. Long before the latter
figure could be reached there would be positive and preventive checks
to further growth, but if these checks were late in being applied,
there would come increased inequality, misery and economic uncertainty,
and an enhanced liability to war.

For us as for other nations a too rapid increase in population spells
this constant danger of war. Our farms cannot absorb more than a
certain proportion of our population without causing lowered wages and
increasing poverty, and we cannot expand our export trade without
entering into the range of international conflict. While therefore an
improved agriculture with high food prices will permit of an increase
in our population, it is {183} advantageous that that increase does not
proceed too rapidly. If we grow to two hundred millions in
seventy-five or one hundred years instead of in thirty-seven, we shall
still be strong enough to protect our present territories and shall
have less occasion to fight for new.

Fortunately our rate of population increase, despite immigration, is
steadily decreasing. In the decade ending 1860 our population
increased 35.6 per cent., in the period 1860 to 1879 at an average
decennial rate of 26.3 per cent., and in the three following decades
25.5 per cent., 20.7 per cent. and 21.1 per cent respectively. The
fall in our natural increase was even greater. While the death rate
has declined[17] the birth rate has fallen off even more rapidly. Our
birth statistics are inadequate, but we can gain some idea of this
decline by comparing the number of children under 5 years of age living
at each census year with the number of women between the ages of 16 to
44 inclusive. In 1800 there were 976 children per 1,000 women in these
ages; in 1830, 877; in 1860, 714; in 1890, 554; in 1910, 508.[18]

For a number of decades a continuat