in which the community of blood is the leading idea, and in which where natural community of blood does not exist, its place is supplied by something which by a legal fiction is looked upon as its equivalent. If, then, we do not ask for scientific, for what we may call physical, accuracy, but if we are satisfied with the kind of proof which is all that we can ever get in the historical sciences--if we are satisfied to speak in a way which is true for popular and practical purposes--then we may say that language has a great deal to do with race, as race is commonly understood, and that race has a great deal to do with community of blood. If we once admit the Roman doctrine of adoption, our whole course is clear. The natural family is the starting-point of everything; but we must give the natural family the power of artificially enlarging itself by admitting adoptive members. A group of mankind is thus formed, in which it does not follow that all the members have any natural community of blood, but in which community of blood is the starting-point, in which those who are connected by natural community of blood form the original body within whose circle the artificial members are admitted. A group of mankind thus formed is something quite different from a fortuitous concurrence of atoms. Three or four brothers by blood, with a fourth or fifth man whom they agree to look on as filling in everything the same place as a brother by blood, form a group which is quite unlike a union of four or five men, none of whom is bound by any tie of blood to any of the others. In the latter kind of union the notion of kindred does not come in at all. In the former kind the notion of kindred is the groundwork of everything; it determines the character of every relation and every action, even though the kindred between some members of the society and others may be owing to a legal fiction and not to natural descent. All that we know of the growth of tribes, races, nations, leads us to believe that they grew in this way. Natural kindred was the groundwork, the leading and determining idea; but, by one of those legal fictions which have such an influence on all institutions, adoption was in certain cases allowed to count as natural kindred.[2]