What then is the reason of this arbitrary inclusion andexclusion? Why should a conception of Kinship, so elastic as toinclude stranger brought into the family by adoption, benevertheless so narrow as to shut out the descendants of a femalemember? To solve these questions, we must recur to the PatriaPotestas. The foundation of Agnation is not the marriage ofFather and Mother, but the authority of the Father. All personsare Agnatically connected together who are under the samePaternal Power, or who have been under it, or who might have beenunder it if their lineal ancestor had lived long enough toexercise his empire. In truth, in the primitive view,Relationship is exactly limited by Patria Potestas. Where thePotestas begins, Kinship begins; and therefore adoptive relativesare among the kindred. Where the Potestas ends, Kinship ends; sothat a son emancipated by his father loses all rights ofAgnation. And here we have the reason why the descendants offemales are outside the limits of archaic kinship. If a womandied unmarried, she could have no legitimate descendants. If shemarried, her children fell under the Patria Potestas, not of herFather, but of her Husband, and thus were lost to her own family.
It is obvious that the organisation of primitive societies wouldhave been confounded, if men had called themselves relatives oftheir mother's relatives. The inference would have been that aperson might be subject to two distinct Patriae Potestates; butdistinct Patriae Potestates implied distinct jurisdictions, sothat anybody amenable to two of them at the same time would havelived under two different dispensations. As long as the Familywas an imperium in imperio, a community within the commonwealth,governed by its own institutions of which the parent was thesource, the limitation of relationship to the Agnates was anecessary security against a conflict of laws in the domesticforum.
The Parental Powers proper are extinguished by the death ofthe Parent, but Agnation is as it were a mould which retainstheir imprint after they have ceased to exist. Hence comes theinterest of Agnation for the inquirer into the history ofjurisprudence. The Powers themselves are discernible incomparatively few monuments of ancient law, but AgnaticRelationship, which implies their former existence, isdiscoverable almost everywhere. There are few indigenous bodiesof law belonging to communities of the Indo-European stock, whichdo not exhibit peculiarities in the most ancient part of theirstructure which are clearly referable to Agnation. In Hindoo law,for example, which is saturated with the primitive notions offamily dependency, kinship is entirely Agnatic, and I am informedthat in Hindoo genealogies the names of women are generallyomitted altogether. The same view of relationship pervades somuch of the laws of the races who overran the Roman Empire asappears to have really formed Part of their primitive usage, andwe may suspect that it would have perpetuated itself even morethan it has in modern European jurisprudence, if it had not beenfor the vast influence of the later Roman law on modern thought.
The Praetors early laid hold on Cognation as the natural form ofkinship, and spared no pains in purifying their system from theolder conception. Their ideas have descended to us, but stilltraces of Agnation are to be seen in many of the modern rules ofsuccession after death. The exclusion of females and theirchildren from governmental functions, commonly attributed to theusage of the Salian Franks, has certainly an agnatic origin,being descended from the ancient German rule of succession toallodial property. In Agnation too is to be sought theexplanation of that extraordinary rule of English Law, onlyrecently repealed, which prohibited brothers of the half-bloodfrom succeeding to one another's lands. In the Customs ofNormandy the rule applies to, by the same mother uterine brothersonly, that is, to brothers but not by the same father; and,limited in this way, it is a strict deduction from the system ofAgnation, under which uterine brothers are no relations at all toone another. When it was transplanted to England, the Englishjudges, who had no clue to its principle, interpreted it as ageneral prohibition against the succession of the half-blood, andextended it to consanguineous brothers, that is to sons of thesame father by different wives. In all the literature whichenshrines the pretended philosophy of law, there is nothing morecurious than the pages of elaborate sophistry in which Blackstoneattempts to explain and justify the exclusion of the half-blood.
