[IDEM libro sexto responsorum. ] §19.1.47.prLucius Titius accepta pecunia ad materias uendendas sub poena certa, ita ut, si non integras repraestauerit² intra statuta tempora, poena conueniatur³, partim datis materiis decessit: cum igitur testator in poenam commiserit neque heres eius reliquam materiam exhibuerit, an et in poenam et in usuras conueniri possit, praesertim cum emptor mutuatus pecuniam usuras grauissimas expendit? Paulus respondit ex contractu, de quo quaeritur, etiam heredem uenditoris in poenam conueniri posse.
[THE SAME in the sixth book of Responses] Lucius Titius, having received money for timber to be sold under a certain penalty, on the condition that if he did not deliver it in full within the established times, he should be sued for the penalty, died after having delivered only part of the timber. Since, therefore, the testator incurred the penalty, and his heir did not deliver the remaining timber, can he be sued both for the penalty and for interest, especially since the buyer, having borrowed money, paid very heavy interest? Paulus answered that, under the contract in question, even the heir of the seller can be sued for the penalty.
in actione quoque ex empto officio iudicis post moram intercedentem usurarum pretii rationem haberi oportere.
Also, in the action on purchase, after default has occurred, account ought to be taken of the interest on the price by the office of the judge.