The woman was the social nucleus, the point to which he returned from his wanderings. In this primitive stage of society, however, the bond between woman and child was altogether more immediate and constraining than the bond between woman and man. The maternal instinct is reinforced by necessary and constant association with the child. We can hardly find a parallel for the intimacy of association between mother and child during the period of lactation; and, in the absence of domesticated animals or suitable foods, and also, apparently, from simple neglect formally to wean the child, this connection is greatly prolonged. The child is frequently suckled from four to five years, and occasionally from ten to twelve.[95] In consequence we find society literally growing up about the woman. The mother and her children, and her children's children, and so on indefinitely in the female line, form a group. But the men were not so completely incorporated in this group as the women, not only because parentage was uncertain and naming of children consequently on the female side, but because the man was neither by necessity nor disposition so much a home-keeper as the women and their children.

The tangential disposition of the male is expressed in the system of exogamy so characteristic of tribal life. The movement toward exogamy doubtless originates in the restlessness of the male, the tendency to make new co-ordinations, the stimulus to seek more unfamiliar women, and the emotional interest in making unfamiliar sexual alliances. But, quite aside from its origin, exogamy is an energetic expression of the male nature. Natural selection favors the process by sparing the groups which by breeding out have heightened their physical vigor.[96] There results from this a social condition which, from the standpoint of modern ideas, is very curious. The man makes, and, by force of convention, finally must make, his matrimonial alliances only with women of other groups; but the woman still remains in her own group, and the children are members of her group, while the husband remains a member of his own clan, and is received, or may be received, as a guest in the clan of his wife. Upon his death his property is not shared by his children, nor by his wife, since these are not members of his clan; but it falls to the nearest of kin within his clan—usually to his sister's children.

The maternal system of descent is found in all parts of the world where social advance stands at a certain level, and the evidence warrants the assumption that every group which advances to a culture state passes through this stage. Morgan gives an account of this system among the Iroquois:

Each household was made up on the principle of kin. The married women, usually sisters, own or collateral, were of the same gens or clan, the symbol or totem of which was often painted upon the house, while their husbands and the wives of their sons belonged to several other gentes. The children were of the gens of their mother. While husband and wife belonged to different gentes, the predominating number in each household would be of the same gens, namely, that of their mothers. As a rule the sons brought home their wives, and in some cases the husbands of the daughters were admitted to the maternal household. Thus each household was composed of a mixture of persons of different gentes, but this would not prevent the numerical ascendency of the particular gens to whom the house belonged. In a village of one hundred and twenty houses, as the Seneca village of Tiotohatton described by Mr. Greenbalge in 1677, there would be several houses belonging to each gens. It presented a general picture of the Indian life in all parts of America at the epoch of European discovery.[97]

Morgan also quotes Rev. Ashur Wright, for many years a missionary among the Senecas and familiar with their language and customs:

As to their family system, when occupying the old log houses, it is probable that some one clan predominated, the women taking in husbands, however, from the other clans, and sometimes for novelty, some of their sons bringing in their young wives until they felt brave enough to leave their mothers. Usually the female portion ruled the house, and were doubtless clannish enough about it. The stores were in common, but woe to the luckless husband or lover who was too shiftless to do his share of the providing. No matter how many children or whatever goods he might have in the house, he might at any time be ordered to pick up his blanket and budge, and after such orders it would not be healthful for him to attempt to disobey; the house would become too hot for him, and, unless saved by the intercession of some aunt or grandmother, he must retreat to his own clan, or, as was often done, go and start a new matrimonial alliance in some other. The women were the great power among the clans as everywhere else. They did not hesitate, when occasion required, to "knock off the horns," so it was technically called, from the head of a chief and send him back to the ranks of the warriors. The original nomination of the chiefs, also, always rested with them.[98]

Traces of the maternal system are everywhere found on the American continent, and in some regions it is still in force. McGee says of the Seri stock of the southwest coast, now reduced to a single tribe, that the claims of a suitor are pressed by his female relatives, and, if the suit is favorably regarded by the mother and uncles of the girl, the suitor is provisionally installed in the house, without purchase price and presents. He is then expected to show his worthiness of a permanent relation by demonstrating his ability as a provider, and by showing himself an implacable foe to aliens. He must support all the female relatives of his bride's family by the products of his skill and industry in hunting and fishing for a year. He is the general protector of the girl's family, and especially of the girl, whose bower and pelican-skin couch he shares, "not as husband, but as continent companion," for a year. If all goes well, he is then permanently received as "consort-guest," and his children are added to the clan of his mother-in-law.[99] With few exceptions, descent was formerly reckoned in Australia in the female line, and the usage survives in some regions. Howitt, in a letter to Professor Tylor, reports of the tribes near Maryborough, Queensland:

When a man marries a woman from a distant locality, he goes to her tribelet and identifies himself with her people. This is a rule with very few exceptions. Of course, I speak of them as they were in their wild state. He becomes a part of, and one of, the family. In the event of a war expedition, the daughter's husband acts as a blood-relation, and will fight and kill his own blood-relations, if blows are struck by his wife's relations. I have seen a father and son fighting under these circumstances, and the son would most certainly have killed the father, if others had not interfered.[100]

In Australia there is also a very sharp social expression of the fact of sex in the division of the group into male and female classes in addition to the division into clans.[101] In the Malay Archipelago the same system is found.

Among the Padang Malays the child always belongs to its mother's suku, and all blood-relationship is reckoned through the wife as the real transmitter of the family, the husband being only a stranger. For this reason his heirs are not his own children, but the children of his sister, his brothers, and other uterine relations; children are the natural heirs of their mother only.... We may assume that, wherever exogamy is now found coexisting with inheritance through the father (as among Rejangs and Bataks, the people of Nias and Timor, or the Alfurs of Ceram and Buru), this was formerly through the mother; and that the other system has grown up out of dislike to the inconveniences arising from the insecure and dependent condition of the husband in the wife's family.[102]