Yet just because of this imperative urging the greater caution is called for in introducing any changes in the laws or customs affecting marriage. Present social and economic conditions are to a great extent chaotic. It would be a sorry thing if in haste we were to establish practices that must come to an end, when we have freed ourselves from the present transition; changes that would not be for the welfare of generations still unborn. It will, however, hardly be denied by any one that reform is needed. All will admit that a change must be made in some direction, and an attempt to say where it should be tried must therefore be faced. Does Nature give us any help in solving the problem? None whatever. It would seem, indeed, that Nature has in some ways arranged the love relation in regard to the needs of the two sexes very badly. But putting this aside for the present, it is clear that in regard to the form of marriage Nature has no preference; all ways are equal to her, provided that the race profits by them, or at least does not suffer too much from them. We found abundant proof of this in our examination of marriage and the family as established already in the animal kingdom; the modes of sexual association offer great variety, no species being of necessity restricted to any one form of union. Polygamy, polyandry, and monogamy all are practised. The family is sometimes patriarchal, though more often it is matriarchal, with the female the centre of it, and her love for the young infinitely stronger and more devoted than the male, though even in this direction there are many and notable exceptions. When we came to study the history of mankind we found similar conditions persisting. Separate groups living as they best could without caring about theories; their sexual conduct ordered by a compromise between the procreative needs on the one hand, and the necessities of the social conditions on the other. Marriage forms, as we understand them, were for long unknown, the relations of the sexes slowly evolving from a more or less restricted promiscuity to a family union at first merely temporary, and only later becoming fixed and permanent. Thus very gradually the primitive instinctive sex impulses underwent expansion, and always in the direction of the control of the individual desires in the interest of the family. The unit of the group or state is the family, therefore sex-customs arise and laws are made not to suit the convenience of the woman or the man, but for the preservation and good of the family. In a word, the children--they are the pivot about which all regulations of marriage should turn.