ses, also, conception has taken place before the first
menstruation.

The older a woman is at the time of her marriage, the longer deferred is
the age at which she naturally becomes sterile. She bears children later
in life, in order to compensate, as it were, for her late commencement.
But although she continues to have children until a more advanced age
than the earlier married, yet her actual child-bearing period is
shorter. Nature does not entirely make up at the end of life for the
time lost from the duties of maternity in early womanhood; for the
younger married have really a longer era of fertility than the older,
though it terminates at an earlier age.

A wife who, having had children, has ceased for three years to conceive,
will probably bear no more, and the probability increases as time
elapses. After the first, births take place with an average interval, in
those who continue to be fertile, of about twenty months.

Nursing women are generally sterile, above all, during the first months
which follow accouchement, because the vital forces are then
concentrated on the secretion of the milk. In a majority of instances,
when suckling is prolonged to even nineteen or twenty months, pregnancy
does not take place at all until after weaning.

Climate has also an influence upon the fertility of marriages. In
southern regions more children are born, fewer in northern. The number
of children is in inverse proportion to the amount of food in a country
and in a season. In Belgium, the higher the price of bread the greater
the number of children, and the greater the number of infant deaths.

The seasons exert a power over the increase of population. The spring of
the year, as has already been stated, is the most favourable to
fecundity. It is not known whether day and night have any effect upon
conception.

The worldly condition seems to have much to do with the size of a
family. Rich and fashionable women have fewer children than their poor
and hard-worked neighbours. Wealth and pleasure seem to be often gladly
exchanged for the title of mother.

But it is our more particular object now to inquire into the _causes of
absolute sterility_ in individual cases, rather than to discuss the
operation of general laws upon the fertility of the community at large,
however inviting such a discussion may be. When marriages are fruitless,
the wife is almost always blamed. It is not to be supposed that she is
always in fault. M