5) During the fifth stage sources of wealth, hitherto unthought of, develop by the training of animals and the breeding of herds. The males, who have hitherto always been the providers of food for the clan, are consequently the possessors of the herds, which now form the main source of subsistence. Lest with the death of the man, his property, the flocks, should be handed over to the former clan, change of descent from the female to the male line is established. The man is now the ruler. The common ancestor, formerly only the leader in war, is now the head of the clan and manager of its possessions. Apart of the head other leaders were necessary in the frequent wars. The latter become preeminent among the other members of the clan and receive individual allotments from the common wealth of the clan.[DU] With the growth of their influence these allotments ripen finally into individual ownership and are inherited by the children. 6) The progress during the sixth stage was caused by the law of inheritance. Inheritance in the male line requires that the father should know his child. The strictest fidelity of the wife is, therefore, a condition sine qua non, her faithfulness is of the greatest racial importance. The woman no less than the man was interested in female purity, in the interest of her children. This strict fidelity, exacted from the wife by men and women alike, leads to the ‘patriarchal family’ as found in the Bible. It is founded upon the marriage of one man with one or more wives.[DV] Now, polygamy is a physical impossibility. Where no man or woman remains unmated, general polygyny or polyandry is practically impossible. The number of the two sexes is nearly equal. If infanticide is not practiced (male infanticide has seldom been practiced, except in Egypt, Exod. I, 16), and war captives or slaves are not available, the general public must be content with one mate.[DW] Polygyny in this way led to “monogamy,” founded upon marriage between single couples with an exclusive cohabitation, as is now the rule in most of the civilized nations. _Female chastity._—All the changes in the marriage relations of the sexes were thus made out of altruistic motives, in the interest of the progeny with the sacrifice of personal comfort. Promiscuity, consanguineous marriage, punaluan family, and the pairing family followed each other in the interest of the health of the offspring. The last change to female monogamy was made in the economic interest of the progeny. The husband in sacrificing his own comfort, while providing food and shelter for his children, must be certain that he is the father of these children. Uncertainty would make him negligent, and the existence of the race would be jeopardized.[DX]