EFFECTS ON POPULATION.
Some writers have maintained that the form of marriage in vogue in a nation exerts an influence on the sex of children; that in polygamy more females, in polyandry more males, are born, and that thus the average of sexes in a community becomes adapted to the prevailing customs. This has been disproved by statistics from Oriental harems, where the births are found to bear the same proportion of sexes as in monogamous coun tries. The scarcity of women where polyandry is the rule has been shown to arise from the destruction of female infants and the selling of the girls to other tribes at a tender age.
The apparently diminished fecundity of savage races is partly apparent only, the small families observed being attributable to large infant mor tality, which is often the deliberate result of the neglect and exposure of infants, often the consequence of ignorance and unsanitary conditions. But there are also certain causes at work in the ruder states of society which directly tend to limit the size of families and react injuriously on the race. One of the most potent of these is premalurc marriage. Mothers of the age *of thirteen years are not uncommon among the Hot tentots, and with the Australians wives as young as twelve, eleven, and even nine, years are frequently seen. Such premature demands upon the sexual function lead to its equally premature exhaustion, and the woman loses all appearance of youth before she has reached middle age. Giving birth to children before she has attained her own full development and stature, it is impossible that the mother can transmit to them either the full physical or mental average of the race, and the consequence is that very early marriages tend to deteriorate the stock. It is not an accidental coincidence that these two races, among whom travellers report the custom of excessively early marriages, stand at the bottom of the scale of humanity.
Scarcely less injurious is the early marriage or the precocious licen tiousness of the males. Either brings with it sexual exhaustion and a lowering of the vigor of mind and body. The truth of this was a matter of observation among even savage nations. The most warlike tribe of North America, the Iroquois, required their braves to remain not only single, but chaste, up to the age of thirty years; the Abipoues of the Gran Chaco of South America, also celebrated for their hardihood, did not per mit marriages until both sexes had reached full growth ; and the edicts of the Incas of Peru prescribed twenty-four as the proper age at which a man should contract marriage.
Early marriages also tend to depreciate the mental culture of a com munity by abbreviating the period which can be devoted to education. The cares and the support of a family are thrown upon young parents who have not had the time to equip themselves in the most.effective man ner for the battle of life. This fact makes itself so apparent in the com plex society of civilization that a steady rise in the ages of those marrying is observable in enlightened countries. This may proceed too far, and produce either a postponement of marriage beyond its most fitting phys iological period, or an aversion to the duties which the bearing and rearing of children entail. This seems to have become the case with the white race whose families have for generations lived in the East ern United States. Statistics show that in the present day the average number of children to each marriage is materially less than it was in the last century. Physicians attribute this to the over-development of the brain and nervous system, to the habit of late marriages in both sexes, and to a repugnance to the annoying cares inseparable from a family of children.