[SCAEUOLA libro primo responsorum. ] §46.1.60.prUbicumque reus ita liberatur a creditore, ut natura debitum maneat, teneri fideiussorem respondit: cum uero genere nouationis transeat obligatio, fideiussorem aut iure aut exceptione liberandum.
[SCAEVOLA, in the first book of Opinions.] He replied that wherever the principal debtor is released by the creditor in such a manner that the debt remains as a natural obligation, the surety is bound; but when the obligation is transferred by a kind of novation, the surety is to be released either by law or by an exception.