e
large families, and there is a law at Sparta, that the father of three
sons should be exempt from military service, and he who has four, from
all the burdens of the State. Yet it is obvious that if there were many
children, the land being distributed as it is, many of these must
necessarily fall into poverty."

The problem in the mind of the Greek philosophers was this.
Over-population is a cause of poverty; under-population is a cause of
weakness. Defectives are an additional burden to the State. How shall
population be so regulated as to established an equilibrium between the
stability of the State, and the highest well-being of the citizens?

The combined philosophy of the Greeks counselled the encouragement of
the best citizens to increase their kind, and the practice of the
exposure of infants and abortion.

A century of debate has raged round the name of Malthus, the great
modern analyst of the population problem. He published his first essay
on population in 1798, a modest pamphlet, which fed so voraciously on
the criticism supplied to it, that it developed into a mighty
contribution to a great social problem, second only in time and in
honour to the work of his great predecessor in economic studies, Adam
Smith.

Malthus's first essay defined and described the laws of multiplication
as they apply only to the lower animals and savage man. It was only in
his revised work, published five years later, that he described moral
restraint as a third check to population.

Adverse criticism had been bitter and severe, and Malthus saw that his
first work had been premature. He went to the continent to study the
problem from personal observation in different countries. He profited by
his observation, and by the writings of his critics, and published his
matured work in 1803.

The distinguishing feature about this edition was the addition of moral
restraint as a check, to the two already described, vice and misery.

Malthus maintained that population has the power of doubling itself
every 25 years. Not that it _does_ so, or _had done_ so, or _will do
so_, but that it is _capable_ of doing so, and he instanced the American
Colonies to prove this statement.

One would scarcely think it was necessary to enforce this distinction,
between what population has done, or is doing, and what it is capable
of doing. But when social writers, like Francesco Nitti (Population and
the Social System, p. 90), urge as an argument ag