birth-rate is lowered. There are two fallacies in their argument. They
overlook the fact that every one of us must die, and that therefore there
is a limit beyond which a death-rate cannot possibly fall, whereas there
is no limit, except zero, to the possible fall in a birth-rate. If a
birth-rate fell to nothing and no children were born, it is obvious that
the population would eventually vanish. The second fallacy is that a low
birth-rate will permanently lower the death-rate. At first a falling
birth-rate increases the proportion of young adults in the population, and,
as the death-rate during early adult life is relatively low, the total
death-rate tends to fall for a time. Sooner or later there is an increase
in the proportion of old people in the population, and, as the death-rate
during old age is high, the total death-rate tends to rise. That is now
happening in England, and these are the _actual facts_ as recorded by the
Registrar-General:

"It may be pointed out that, though the effect of the fall in the
birth-rate has hitherto been an a sense advantageous in that it has
increased the proportions living at the working ages, a tendency to the
reversal of this fact has already set in, and may be expected to
develop as time goes on....

"The general characteristics of the figures indicate very clearly the
effects of the long-continued decline in the birth-rate of this
country, and show, by the example of France, the type of
age-distribution which a further continuance of the decline is likely
to produce. The present age-distribution of the English population is
still favourable to low death-rates, but is becoming less so than it
was in 1901. The movements along the curve of the point of maximum
heaping up population, referred to on page 61 (See [Reference:
Population]), has shifted this from age 20-25 to a period ten years