This power of calling on the creditor to prove that he had really made the loan was extended to cases where the debtor had not gone through the form of the contract literis, but had merely given a general acknowledgment of debt (cautio), such as is spoken of in the text. Although cautiones were not properly contracts, but proofs of a contract, yet as they were protected by the same exception (C. iv. 30. 3), they were equivalent to and superseded contracts literis. It will be noticed that the text uses the words scriptura obligetur, as if the obligation was created by the writing. This may account for Justinian at once telling us that contracts literis were obsolete, and yet giving them a place in the Institutes.

After a certain number of years-first one, then five, and fixed by Justinian at two-the debtor was bound by the writing conclusively. (C. iv. 30. 14.) During this period, however, the debtor who had not really received the money need not wait to be sued ; he might protest in a public act against any writing by which he admitted a debt, or bring an action against the creditor to compel him to give it up (C. iv. 30. 7); and a constitution in the Code (iv. 30. 14. 4) permitted him to make his exception perpetual by a formal announcement to the creditor of his intention to do so, and by his going through certain forms. If it was proved that the debtor had falsely denied having received what he had really received, Justinian ordered by a Novel (18. 8) that he should pay double the amount.

TIT. XXII. DE CONSENSU OBLIGATIONE.

Consensu fiunt obligationes in emptionibus venditionibus, locationibus conductionibus, societatibus, mandatis. Ideo autem istis modis consensu dicitur obligatio contrahi, quia neque scriptura neque præsentia omnimodo opus est, ac ne dari quidquam necesse est, ut substantiam capiat obligatio, sed sufficit eos, qui negotium gerunt, consentire. Unde inter absentes quoque talia negotia contrahuntur, veluti per epistulam aut per nuntium. Item in his contractibus alter alteri obligatur in id, quod alterum alteri ex bono et æquo præstare oportet, cum alioquin in verborum obligationibus alius stipuletur, alius promittat.

Obligations are formed by the mere consent of the parties in the contracts of sale, of letting to hire, of partnership, and of mandate. An obligation is, in these cases, said to be made by the mere consent of the parties, because there is no necessity for any writing, nor even for the presence of the parties; nor is it requisite that anything should be given to make the contract binding, but the mere consent of those between whom the transaction is carried on suffices. Thus these contracts may be entered into by those who are at a distance from each other by means of letters, for instance, or of messengers. In these contracts each party is bound to the other to render him all that equity demands, while in verbal obligations one party stipulates and the other promises.

GAI. iii. 135. 137.

We now pass to contracts which belong to the jus gentium, which have nothing of the peculiar characteristics of the old civil

law of Rome, and which are perfected by the simple consent of the parties. As is remarked in the concluding words of the text, these contracts by simple consent, unlike the contracts of which we have hitherto spoken, are bilateral; there is something which binds both parties; whereas the older and peculiarly Roman contracts were only unilateral. In a stipulation, for instance, it was only the promissor that was bound. Commodatum, depositum, and pignus were only bilateral in the sense that they gave rise to actiones contraria under certain circumstances, so that then both parties were bound by them. These contracts consensu' were not enforced by actions stricti juris, such as were proper to the peculiarly Roman contracts of mutuum, stipulation, and contracts made literis, but by actions bona fidei, i.e. prætorian actions, in which equitable principles were permitted to govern the decision. (See Introd. sec. 106.)

TIT. XXIII. DE EMPTIONE ET VENDITIONE.

Emptio et venditio contrahitur, simulatque de pretio convenerit, quamvis nondum pretium numeratum sit ac ne arra quidem data fuerit. Nam quod arræ nomine datur, argumentum est emptionis et venditionis contractæ. Sed hæc quidem de emptionibus et venditionibus, quæ sine scriptura consistunt, optinere oportet: nam nihil a nobis in hujusmodi venditionibus innovatum est. In his autem, quæ scriptura conficiuntur, non aliter perfectam esse emptionem et venditionem constituimus, nisi et instrumenta emptionis fuerint conscripta vel manu propria contrahentium, vel ab alio quidem scripta, a contrahente autem subscripta et, si per tabellionem fiunt, nisi et completiones acceperint et fuerint partibus absoluta. Donec enim aliquid ex his deest, et poenitentiæ locus est et potest emptor vel venditor sine pœna recedere ab emptione. Ita tamen impune recedere eis concedimus, nisi jam arrarum nomine aliquid fuerit datum : hoc etenim subsecuto, sive in scriptis sive sine scriptis venditio celebrata est, is, qui recusat adimplere contractum, si quidem emptor est, perdit, quod dedit, si vero venditor, duplum restituere compellitur, licet nihil super arris expressum est.

The contract of sale is formed as soon as the price is agreed upon, although it has not yet been paid, nor even an earnest given; for what is given as an earnest only serves as proof that the contract has been made. This must be understood of sales made without writing; for with regard to these we have made no alteration in the law. But, where there is a written contract, we have enacted that a sale is not to be considered completed unless an instrument of sale has been drawn up, being either written by the contracting parties, or at least signed by them, if written by others; or if drawn up by a tabellio, it must be formally complete and finished throughout; for as long as any of these requirements is wanting, there is room to retract, and either the buyer or seller may retract without suffering loss: that is, if no earnest has been given. If earnest has been given, then, whether the contract was written or unwritten, the purchaser, if he refuses to fulfil it, loses what he has given as earnest, and the seller, if he refuses, has to restore double; although no agreement on the subject of the earnest was expressly made.

GAI. iii. 139; C. iv. 21. 17.

The contract of sale belonging to the jus gentium was attended with none of those material symbols which characterised the formation of contracts under the civil law. Directly one person agreed to sell a particular thing, and another to buy it, for a fixed sum of money, the contract was complete; no thing need be delivered, no money paid, in order that an obligation should arise. On the mutual consent being given, the seller was bound to deliver, the buyer to pay the price. The change which Justinian here introduced is that, when, in giving this mutual consent, they agree that the terms of the contract shall be reduced to writing, they shall be considered not to have consented to the contract until all the formalities have been gone through.

The arra were either signs of a bargain having been struck, as, for instance, when the buyer deposited his ring with the seller (D. xix. 1. 11. 6), or consisted of an advance of a portion of the purchase-money. They were also intended as a proof that the purchase had been made. Justinian gave these deposits a new character by making them the measures of a forfeit in case either party wished to recede from his bargain, it being open to either party to retract if he chose to incur this forfeit. This power of retracting by forfeiture of the deposit, or double its value, was a great change in the law; and when Justinian says nihil in hujusmodi venditionibus innovatum est, he must be understood only to be referring to unwritten contracts of sale, in which there was no deposit made as earnest. It will be seen from the text that this power of retractation was given whether the contract was made with writing or without.

Besides a buyer and a seller, there must, in a contract of sale, be a fixed price and a particular thing sold. The jurists are very minute in their distinctions of the nature of the thing sold. There is a distinction with regard to things future and uncertain forming the object of a sale, which is worth mentioning. Either a proportionate price may be agreed to be paid on a greater or lesser number of things that may be actually realised, as so much a head for all the fish I catch to-day,' which is termed rei sperata emptio; or a definite sum may be agreed on as the price of the possibility of any number of things, more or less, being realised, as so much for the chance of all the fish I catch to-day;' and this was termed spei emptio. (D. xviii. 1. 8. 1.)

1. Pretium autem constitui oportet: nam nulla emptio sine pretio esse potest. Sed et certum pretium esse debet. Alioquin si ita inter aliquos convenerit, ut, quanti Titius rem æstimaverit, tanti sit empta inter veteres satis abundeque hoc dubitabatur, sive constat venditio sive non. Sed nostra decisio ita hoc constituit, ut, quotiens sic composita sit venditio quanti ille restimaverit,' sub hac condicione staret

1. It is necessary that a price should be agreed upon, for there can be no sale without a price. And the price must be fixed and certain. If the parties agree that the thing shall be sold at the sum at which Titius shall value it, it was a question much debated among the ancients, whether in such a case there is a sale or not. We have decided, that when a sale is made for a price to be fixed by a third person, the contract shall be binding

GAI. iii. 140;

GAI. iii. 141; D. xviii. 1. 1. 11; C. iv. 64. 7.

A sale and an exchange differ so little that it might seem natural to treat the promise to exchange as raising an obligation equally with the promise to deliver a thing sold; it was indeed the opinion of the Sabinians that it did so; but this opinion did not prevail, and the law recognised no obligation as existing under an agreement to exchange unless one party had delivered to the other the thing he had promised. Ex placito permutationis nulla re secuta, constat nemini actionem competere. (C. iv. 64. 3.) Thus the distinction between sale and exchange was that in the former the contract was made consensu, in the other re: when one party had delivered the thing, the other was obliged to give the other thing. Permutatio ex re tradita initium obligationi præbet. (D. xix. 4. 1. 2.)

In a contract of sale the seller was not bound to make the buyer absolute master (dominus) of the thing sold, as he would have been in a stipulation. (D. xviii. 1. 25. 1.) What he was bound to do was this: 1st. He was bound to deliver the thing itself (præstare, tradere) (D. xix. 1. 11. 2), to give free and undisturbed possession of it (possessionem vacuam præstare) (D. xix. 1. 2. 1), and to give lawful possession of it (præstare licere habere). (D. xix. 1. 30. 1.) 2ndly. He was bound, if the buyer was disturbed in his possession by the real owner (which was termed evictio), to recompense him for what he lost. (D. xix. 1. 11. 2.) And 3rdly. To secure the buyer against secret faults; if such faults were discovered, either compensation might be claimed by an actio æstimatoria, to a greater or less amount, according as the seller had or had not knowledge of the defect (D. xix. 1. 13), or, at the option of the buyer, the contract might be rescinded, and the thing returned (which was termed redhibitio-redhibere est facere ut rursus habeat venditor quod habuerit). (D. xxi. 1. 21.) In order to fortify his position, the buyer could stipulate with the seller, and make the seller promise that he would give, not the free possession only, but the dominium of the thing, and that he would pay the buyer double the price if the buyer was evicted. The buyer would then have an action ex stipulatu to enforce the undertaking. Even if there was no such stipulation actually made, yet after it had become usual to make such stipulations, custom was held to have so far imported the promise into the contract of sale that the buyer, in bringing the action appropriate to his contract, actio ex empto, could obtain double the price in case of eviction, as this action was bona fidei, i.e. the parties could be placed in a fair position towards each other, and it was considered that to have given the promise to pay double the price in case of eviction was a duty of the seller. (D. xxi. 2.2.)

The buyer was bound to make the seller the real owner of the money paid as the price (emptor nummos venditoris facere cogitur, D. xix. 1. 11. 2), and was also bound to pay interest on the purchase money from the day when he had received the thing sold. (D. xix. 1. 13. 20.)

The lines cited in the text are from П. vii. 472; probably the