try, then B might have inherited; not as heir to A his half-brother, but as heir to their common father, who was the perſon laſt actually ſeiſed[1].
This total excluſion of the half blood from the inheritance, being almoſt peculiar to our own law, is looked upon as a ſtrange hardſhip by ſuch as are unacquainted with the reaſons on which it is grounded. But theſe cenſures ariſe from a miſapprehenſion of the rule; which is not ſo much to be conſidered in the light of a rule of deſcent, as of a rule of evidence; an auxiliary rule, to carry a former into execution. And here we muſt again remember, that the great and moſt univerſal principle of collateral inheritances being this, that an heir to a feudum antiquum muſt be of the blood of the firſt feudatory or purchaſor, that is, derived in a lineal deſcent from him; it was originally requiſite, as upon gifts in tail it ſtill is, to make out the pedigree of the heir from the firſt donee or purchaſor, and to ſhew that ſuch heir was his lineal repreſentative. But when, by length of time and a long courſe of deſcents, it came (in thoſe rude and unlettered ages) to be forgotten who was really the firſt feudatory or purchaſor, and thereby the proof of an actual deſcent from him became impoſſible; then the law ſubſtituted what ſir Martin Wright[2] calls a reaſonable, in the ſtead of an impoſſible, proof: for it remits the proof of an actual deſcent from the firſt purchaſor; and only requires, in lieu of it, that the claimant be next of the whole blood to the perſon laſt in poſſeſſion; (or derived from the ſame couple of anceſtors) which will probably anſwer the ſame end as if he could trace his pedigree in a direct line from the firſt purchaſor. For he who is my kinſman of the whole blood can have no anceſtors beyond or higher than the common ſtock, but what are equally my anceſtors alſo; and mine are vice verſa his: he therefore is very likely to be derived from that unknown anceſtor of mine, from whom the inheritance deſcended. But a kinſman of the half blood has but one half of his anceſtors above the common ſtock the ſame as mine; and therefore there is not the
