[IDEM libro sexto quaestionum. ] §28.3.19.prSi ego et Titius instituti simus et a nobis postumus exheredatus sit, a substitutis nostris non sit exheredatus, Titio defuncto ne ego quidem adire potero: iam enim propter instituti personam, a quo postumus exheredatus est, in cuius locum substitutus uocatur, a quo postumus exheredatus non est, ruptum est testamentum.
[THE SAME, Questions, Book 6.] If I and Titius have been instituted as heirs, and a posthumous child has been disinherited by us, but has not been disinherited by our substitutes, then if Titius dies, not even I will be able to enter upon the inheritance; for the testament is already broken on account of the person of the instituted heir, by whom the posthumous child was disinherited, in whose place a substitute is called by whom the posthumous child was not disinherited.
§28.3.19.1Sed si ego et Titius inuicem substituti simus, quamuis in partem substitutionis exheredatus non sit, mortuo uel repudiante Titio me posse adire puto et ex asse heredem esse.
But if I and Titius have been mutually substituted for each other, although the posthumous child was not disinherited in respect of the share of the substitution, I think that if Titius dies or rejects the inheritance, I can enter and be heir to the whole estate.
§28.3.19.2In prima tamen specie et si uiuat Titius, neque ego sine illo neque ipse sine me adire poterit, quia incertum est, an adhuc altero omittente rumpatur testamentum: itaque simul adire possumus.
Nevertheless, in the first case, even if Titius is alive, neither I without him nor he without me will be able to enter, because it is uncertain whether, if the other should decline, the testament may still be broken; therefore, we can enter at the same time.