objectively ascertained, is perceptible and strictly defined. But § 75. where the object of the obligation is some other act-e. g. the rendering of a service, the building of a house, the restoration of a thing which already belongs to me, or the procuring of a jus in re not recognized by the civil law (say, a superficies)—in all these cases the civil law has no means of determining the value of the obligation, which is not expressed in the value of the object of the act. Hence an obligatio faciendi is called an incerta obligatio, because its value is not ascertained, not perceptible, not strictly defined by the contents of the agreement itself.

An obligation to procure ownership in a thing which is only alternatively determined, or which, though not a res fungibilis, is only generically determined, is not a direct obligation to procure ownership, but an obligation, in the first instance, to select. Hence it is not an obligatio dandi, but an obligatio faciendi, an incerta obligatio. There is no definite object representing and embodying the value of the obligation. It is only by performance on the part of the debtor-only, that is, by an actual carrying out of the selection through the procuring of ownership, the 'dare' of a certa res-that the object of the obligation is finally determined. But an obligation to procure ownership in a certain quantity of res fungibiles, e. g. in a certain amount of wheat, is an obligatio dandi and an obligatio certa. The value of the act to be performed is determinable by reference to every specified amount of the thing in question, and the procuring of res fungibiles involves, not a selecting between things which are different, but a counting, or weighing, or measuring, of things which are treated without distinction as equal (tantundem ejusdem generis est idem, supra, p. 322). In such a case the direct object of the obligation is the procuring of ownership.

APPENDIX.

Between an obligation to pay money and an obligation to make over any other kind of thing there is a difference which is important in several respects. A money obligation is an obligation to make over a sum of money, to make over, that is, a certain quantum of value, not

$75 App. of things. Such an obligation can only be performed through the medium of money, in the legal sense of the term, i. e. through the medium of such things as are declared by law to be representatives of abstract value, to be-in short-legal tender.' Modern Germany has adopted the gold standard. Within the German Empire only the imperial gold coins are money, in the legal sense; the silver, nickel, and copper coins are only money in a limited sense, i.e. they are only legal tender up to certain amounts. The one-dollar pieces are treated by a fiction as gold coins. Bank notes and treasury bills are money in the economic sense only though they are used, in point of fact, as representatives of abstract value, they are no more legal tender than foreign money is legal tender. A debtor, therefore, who desires to discharge a money obligation, can require his creditor to accept in payment whatever is money in the legal sense, but he cannot require the creditor to accept anything else. A money obligation is not an obligation to make over a certain quantity of definite things. If A owes B one hundred marks, he does not owe B a hundred one-mark pieces-that would be to owe a quantity of res fungibiles-on the contrary, B could decline to take the hundred onemark pieces in payment. What A owes is one hundred marks value, and this value A can pay in imperial gold coinage of any kind: in five twenty-mark pieces or ten ten-mark pieces, in one twenty-mark piece and eight ten-mark pieces, and so forth. Of course an agreement may provide for the payment of coins of a particular kind; I may, for example, stipulate for payment of one twenty-mark piece or of twenty one-mark pieces. But an obligation to pay coins of a particular kind would not be a money obligation, but an obligation to make over a certain number of res fungibiles, differing in no way from an ordinary obligation to make over a thing other than money. For a person who owes money does not owe any particular coins; he simply owes a sum of money, i. e. a certain quantum of value, which he can pay in the form of any legal tender he chooses. The difference between an obligation to pay money and an obligation to provide any other res fungibiles becomes material in distinguishing a contract of sale from a contract of exchange (cp. infra, p. 416, n. 1).

$76.

§ 76. Stricti Furis Negotia and Bonae Fidei Negotia.

The effect of some contracts is to produce a liability which is precisely determined and accurately defined. The effect of others is to produce a liability which is not precisely determined nor accurately defined and which is (at the outset at least) indefinable. Contracts

of the former kind are called stricti juris negotia, contracts of the § 76. latter kind bonae fidei negotia,

Stricti juris negotia are contracts which bind the parties to the exact performance of that which they promised. The Roman stipulatio (which may be compared to a modern bill of exchange, infra, § 80) furnishes an example. Negotia stricti juris are interpreted literally. Nothing is due that has not been promised. The contents of the obligation to which they give rise are a matter of calculation and can be accurately determined. If a person has promised by a negotium stricti juris dare certam rem, the resulting obligatio is certa in the full sense of the term. Nothing more is due than what has been promised.

Bonae fidei negotia, on the other hand, are contracts which bind the parties to perform, not what they actually promised, but rather whatever can be fairly and reasonably required in each particular case-which may be either more, or less, than what was promised. The resulting liability is not a matter of calculation, and will be variously determined according to circumstances. obligatio is always incerta, even where there is an express promise the direct object of which is dare certam rem, as, for example, in the case of an exchange. The nature of the parties' liability is expressed in the words: quidquid dare facere oportet ex bona fide (cp. p. 280).

The

Bonae fidei negotia, such as sale, exchange, hire, partnership, always operate to impose certain duties on the parties, whether such duties were expressly undertaken or not.

1. The parties must exercise care, 'diligentia.' The degree of care required is uniformly omnis (or summa) diligentia, or, as it is often called, diligentia diligentis (sometimes termed diligentissimi) patrisfamilias. In other words, they are bound to behave in the way any careful man would behave under the circumstances. If either party fall short of this standard, he is thereby guilty of what is called 'culpa levis,' and is liable to compensate the other for any damage resulting from such culpa levis. It is only in exceptional cases that the liability is restricted to dolus, i. e. to intentional and malicious damage, or to culpa lata, i. e. to carelessness so gross as necessarily to imply an intention on the part of the person charged

§ 76. with it. The separate cases of this kind will be specified hereafter in discussing the separate contracts.

2. The parties are liable in full damages for delay in performing, for inadequate performance, or for non-performance. The debtor must compensate the creditor for 'quod interest,' for his (the creditor's) 'interest,' i. e. for all damage which he (the creditor) has suffered as a direct consequence of the debtor's wilful or negligent non-performance or misperformance. In case of delay (mora solvendi) the debtor becomes liable to pay interest on account of such delay. The rule is different in regard to stricti juris negotia (supra, p. 285).

The debtor, however, is never liable for an accident: casus a nemine praestatur. An accident, within the meaning of the law of contract, means any event which takes place without the debtor's act or default. Thus an accident may render performance, on his part, impossible (if, for example, the merchandise he agreed to procure is destroyed), and in that case he is discharged. Only a debtor who is in mora solvendi is, by way of punishment, made liable even for casus; in other words, casus does not discharge him, but leaves him liable to compensate the creditor to the extent of his (the creditor's) 'interest.'

According to Roman law a debtor was not deemed in mora solvendi the moment the debt became due; in addition to the debt being due there had to be a demand (interpellatio) on the part of the creditor.

L. 32 pr. D. de usur. (22, 1) (MARCIANUS): Mora fieri intelligitur non ex re sed ex persona, id est, si interpellatus opportuno loco non solverit.

§ 77.

II. THE MODES IN WHICH OBLIGATIONS ARISE.

877. Contracts and Delicts.

An obligation arises either from a declaration of consensus, i.e. ex contractu, or from an act done in contravention of the law, i.e. ex delicto. In the former case the obligation arises by virtue of

the will of the debtor, in the latter case it arises contrary to the will § 77. of the debtor.

Besides the obligationes ex contractu, we have the cases of what are called 'obligationes quasi ex contractu,' which arise from facts bearing a certain resemblance to contracts. Besides the obligationes ex delicto we have the cases of what are called 'obligationes quasi ex delicto,' which arise from facts bearing a certain resemblance to delicts.

A. CONTRACTUAL OBLIGATIONS.

878. Introduction.

Roman law adhered all along to the principle that not every § 78. promise which is intended to create an obligation is legally valid and actionable. In order that such a promise may be legally valid and actionable, Roman law requires, in addition to the promise, some definite ground recognized by the law, a so-called 'causa civilis.' Hence the somewhat restricted sense in which the term 'contractus' is used in Roman law. A contract in the Roman sense is not any declaration of consensus which is intended to create an obligation, but only a declaration of consensus whin results in an obligation actionable by the civil law.

A promise which is intended to create an obligation may become actionable by the civil law in one of four ways: (1) re, i.e. by the fact that, in addition to the obligatory consensus, there is a delivery of property (res) by one party entitling him to claim a re-delivery or counter-performance (as the case may be) from the other (Real Contracts, § 79); (2) verbis, i.e. by the fact that the obligatory consensus is orally expressed in a particular form, viz. in the form of a question and answer (Verbal Contracts, § 80); (3) literis, i. e. by the fact that the obligatory consensus is expressed in the form of an entry in the domestic account-book (Literal Contracts, § 81); (4) in certain exceptional cases by a simple obligatory consensus, without more (Consensual Contracts, § 82).

These four classes of contracts constitute the contractual system of Roman law.