[IDEM libro duodecimo responsorum. ] §28.6.45.prLucius Titius legitimum filium et alterum naturalem heredes instituit eosque inuicem substituit: Titianus legitimus filius, quem pater anniculum reliquit, post patris mortem impubes decessit superstite matre et fratre naturali, quem etiam coheredem habebat: quaero an hereditas eius ad Titium naturalem fratrem ex causa substitutionis pertineat an uero ad matrem.
[The same, from his twelfth book of Opinions.] Lucius Titius instituted his legitimate son and another natural son as his heirs, and substituted them reciprocally for one another. The legitimate son Titianus, whom his father left when he was one year old, died after his father's death while still under the age of puberty, leaving surviving his mother and his natural brother, whom he also had as a co-heir. I ask whether his inheritance belongs to his natural brother Titius by virtue of the substitution, or rather to his mother.
respondi ad primum casum non existentium heredum substitutionem de qua quaeritur pertinere, non ad sequentem, si quis eorum postea decessisset intra pubertatem, cum in naturalis filii persona duplex substitutio locum habere non poterit: et ideo ad matrem legitimi filii hereditas ab intestato pertinet.
I replied that the substitution in question relates to the first case, of heirs not existing, and not to the subsequent case, if any of them should afterwards die within the age of puberty, since a double substitution cannot take place in the person of a natural son; and therefore the inheritance of the legitimate son belongs to his mother by intestate succession.
§28.6.45.1Paulus respondit, si omnes instituti heredes omnibus inuicem substituti essent, eius portionem, qui quibusdam defunctis postea portionem suam repudiauit, ad eum solum, qui eo tempore superuixit, ex substitutione pertinere.
Paulus replied that if all the instituted heirs had been substituted reciprocally for all, the share of the one who, after some had died, subsequently rejected his share, belongs by virtue of the substitution only to the one who survived at that time.