ne or quasi-uterine gestation which
brings the young into the world alive, an average of 56 eggs
is quite sufficient.

Man is no exception to these laws. His evolution has been steadily in
the direction of diminishing fertility and increasing parental care.
This does not necessarily imply that the modern European loves his
children better than the savage loves his. It is grim necessity, not
want of affection, which determines the treatment of children by their
parents over a great part of the world, and through the greater part of
human history. The homeless hunters, who represent the lowest stage of
savagery, are now almost extinct. In these tribes the woman has to
follow the man carrying her baby. Under such conditions the chances of
rearing a large family are small indeed. Very different is the life of
the grassland nomads, who roam over the Arabian plateau and the steppes
of Central Asia. These tribes, who really live as the parasites of their
flocks and herds, depending on them entirely for subsistence, often
multiply rapidly. Their typical unit is the great patriarchal family, in
which the _sheikh_ may have scores of children by different mothers.
These children soon begin to earn their keep, and are taken care of. If,
however, the patriarch so chooses, Hagar with her child is cast adrift,
to find her way back to her own people, if she can. The grasslands are
usually almost as full as they can hold. A period of drought, or
pressure by rivals, in former times sent a horde of these hardy
shepherds on a raid into the nearest settled province; and if, like the
Tartars, they were mounted, they usually killed, plundered, and
conquered wherever they went, until the discovery of gunpowder saved
civilisation from the recurrent peril of barbarian inroads. Barbarians
of another type, hunters with fixed homes, seldom increase rapidly,
partly because the dangers of forest-life for young children are much
greater than on the steppe.

In the primitive river-valley civilisations, such as Egypt and
Babylonia, the conditions of increase were so favourable that a dense
population soon began to press upon the means of subsistence. In Egypt
the remedy was a centralised government which could undertake great
irrigation works and intensive cultivation. In Babylonia, for the first
time in history, foreign trade was made to support a larger population
than the land itself could maintain. There was little or no infanticide
in B