De rerum permutatione
(Concerning the exchange of property.)
1 Paulus libro trigesimo secundo ad edictum. Sicut aliud est vendere, aliud emere, alius emptor, alius venditor, ita pretium aliud, aliud merx. at in permutatione discerni non potest, uter emptor vel uter venditor sit, multumque differunt praestationes. emptor enim, nisi nummos accipientis fecerit, tenetur ex vendito, venditori sufficit ob evictionem se obligare possessionem tradere et purgari dolo malo, itaque, si evicta res non sit, nihil debet: in permutatione vero si utrumque pretium est, utriusque rem fieri oportet, si merx, neutrius. sed cum debeat et res et pretium esse, non potest permutatio emptio venditio esse, quoniam non potest inveniri, quid eorum merx et quid pretium sit, nec ratio patitur, ut una eademque res et veneat et pretium sit emptionis. 1Unde si ea res, quam acceperim vel dederim, postea evincatur, in factum dandam actionem respondetur. 2Item emptio ac venditio nuda consentientium voluntate contrahitur, permutatio autem ex re tradita initium obligationi praebet: alioquin si res nondum tradita sit, nudo consensu constitui obligationem dicemus, quod in his dumtaxat receptum est, quae nomen suum habent, ut in emptione venditione, conductione, mandato. 3Ideoque Pedius ait alienam rem dantem nullam contrahere permutationem. 4Igitur ex altera parte traditione facta si alter rem nolit tradere, non in hoc agemus ut res tradita nobis reddatur, sed in id quod interest nostra illam rem accepisse, de qua convenit: sed ut res contra nobis reddatur, condictioni locus est quasi re non secuta.
1 Paulus, On the Edict, Book XXXII. Just as it is one thing to sell, and another to buy, and as a difference exists between purchaser and vendor, so the price is one thing, and the property another. In an exchange, however, it cannot be ascertained which is the purchaser and which the vendor. Exchanges differ greatly, for a purchaser is liable to an action on sale, unless he pays the purchase-money to the vendor; and it is sufficient for the vendor to bind himself in case of eviction, to deliver possession and be free from fraud, and therefore, if the property sold is not lost by a better title, he owes nothing. In an exchange, however, if the property of each party is regarded as the price of that of the other, the title to each article must pass, but if it is considered as merchandise, neither is required to transfer the ownership. But, while in a sale there must be both property and a price, it cannot be ascertained in an exchange which is the property, and which is the price, nor does reason permit that the same thing shall be at once the property sold and the price of what is purchased. 1Wherefore, if one of the articles which I have received or given is afterwards taken away through a better title, it is held that an action in factum should be granted. 2Moreover, purchase and sale is contracted by the mere will of the parties consenting to the same; an exchange, however, gives rise to an obligation by the delivery of the property. Otherwise, if the property was not delivered, we hold that an obligation could be contracted by mere consent, which is only applicable to agreements of this kind which have their own specific designations, as purchase, sale, lease, and mandate. 3Therefore Pedius says that where a party gives property which belongs to another an exchange is not contracted. 4Hence, where delivery is made by one party, and the other refuses to deliver his property, we cannot institute proceedings for the reason that it is to our interest to have received the article concerning which the agreement was made; but there will be ground for a personal suit for recovery to compel the property to be restored to us, just as if the transaction had not taken place.
2 Idem libro quinto ad Plautium. Aristo ait, quoniam permutatio vicina esset emptioni, sanum quoque furtis noxisque solutum et non esse fugitivum servum praestandum, qui ex causa daretur.
2 The Same, On Plautius, Book V. Aristo says that an exchange resembles a sale in a case where a guarantee must be given that a slave is sound, and free from liability to arrest for theft or damage committed, and that he is not a fugitive who must be surrendered on this account.