Of species that exhibit no sort of parental care, the average of forty-nine gives 1,040,000 eggs to a female each year; while among those which make nests or any apology for nests the number is only about 10,000. Among those which have any protective tricks, such as carrying the eggs in pouches or attached to the body, or in the mouth, the average number is under 1000; while among those whose care takes the form of uterine 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.