QUASI-CONTRACTUS. A term used in the civil law. A quasi-contract is the act 
of a person, permitted by law, by which he obligates himself towards 
another, or by which another binds himself to him, without any agreement 
between them. 
     2. By article 2272 of the Civil Code of Louisiana, which is translated 
from article 1371 of the Code Civil, quasi-contracts are defined to be "the 
lawful and purely voluntary acts of a man, from which there results any 
obligation whatever to a third person, and sometime a reciprocal obligation 
between the parties." In contracts, it is the consent of the contracting 
parties which produces the obligation; in quasi-contracts no consent is 
required, and the obligation arises from the law or natural equity, on the 
facts of the case. These acts are called quasi-contracts, because, without 
being contracts, they bind the parties as contracts do. 
     3. Quasi-contracts may be multiplied almost to infinity. They are, 
however, divided into five classes: such "relate to the voluntary and 
spontaneous management of the affairs of another, without authority; the 
administration of tutorship; the management of common property; the 
acquisition of an inheritance; and the payment of a sum of money or other 
thing by mistake, when nothing was due. 
     4.-1. Negotiorum gestio. When a man undertakes of his own accord to 
manage the affairs of another, the person assuming the agency contracts the 
tacit engagement to continue it, an& complete it, until the owner shall be 
in a condition to attend to it himself. The obligation of such a person is, 
1st. To act for the benefit of the absentee. 2d. He is commonly answerable 
for the slightest neglect. 3d. He is bound to render an account of his 
management. Equity obliges the proprietor, whose business has been well 
managed, 1st. To comply with the engagements contracted by the manager in 
his name. 2d. To indemnify the manager in all the engagements he has 
contracted. 3d. To reimburse him all useful and necessary expenses. 
     5.-2. Tutorship or guardianship, is the second kind of quasi-
contracts, there being no agreement between the tutor and minor. 
     6.-3. When a person has the management of a common property owned by 
himself and others, not as partners, he is bound to account for the profits, 
and is entitled to be reimbursed for the expenses which he has sustained by 
virtue of the quasi-contract which is created by his act, called communio 
bonorum. 
     7.-4. The fourth class is the aditio hereditatis, by which the heir 
is bound to pay the legatees, who cannot be said to have any contract with 
him or with the deceased. 
     8.-5. Indebiti solutio, or the payment to one of what is not due to 
him, if made through any mistake in fact, or even in law, entitles him who 
made the payment to an action against the receiver for repayment, condictio 
indebiti. This action does not lie, 1. If the sum paid was due ex equitate, 
or by a natural obligation. 2. If he who made the payment; knew that nothing 
was due, for qui consulto dat quod non, debebat, proesumitur donare. 
     9. Each of these quasi-contracts has an affinity with some contract; 
thus the management of the affairs of another without authority, and 
tutorship, are compared to a mandate; the community of property, to a 
partnership; the acquisition of an inheritance, to a stipulation; and the 
payment of a thing which is not due, to a loan. 
    10. All persons, even infants and persons destitute of reason, who are 
consequently incapable of consent may be obliged by the quasi-contract, 
which results from the act of another, and may also oblige others in their 
favor; for it is not consent which forms these obligations; they are 
contracted by the act of another, without any act on our part. The use of 
reason is indeed required in the person whose act forms the quasi-contract, 
but it is not required in the person by whom or in whose favor the 
obligations which result from it are contracted. For instance, if a person 
undertakes the business of an infant or a lunatic; this is a quasi-contract, 
which obliges the infant or the lunatic to the person undertaking his 
affairs, for what he has beneficially expended, and reciprocally obliges the 
person to give an account of his administration or management. 
    11. There is no term in the common law which answers to that of quasi-
contract; many quasi-contracts may doubtless be classed among implied 
contracts; there is, however, a difference between them, which an example 
will make manifest. In case money should be paid by mistake to a minor, it 
may be recovered from him by the civil law, because his consent is not 
necessary to a quasi-contract but by the common law, if it can be recovered, 
it must be upon an agreement to which the law presumes he has consented, and 
it is doubtful, upon principle, whether such recovery could be had. 
     See generally, Just. Inst. b. 3, t. 28 Dig. b. 3, tit. 5; Ayl. Pand. b. 
4, tit. 31 1 Bro. Civil Law, 386; Ersk. Pr. Laws of Scotl. b. 3, tit. 3, s. 
16; Pardessus, Dr. Com. n. 192, et seq.; Poth. Ob. n. 113, et seq.; Merlin, 
Rep. Riot Quasi-contract; Menestrier, Lecons Elem. du Droit Civil Romain, 
liv. 3, tit. 28; Civil Code of Louisiana, b. 3, tit. 5; Code Civil, liv. 3, 
tit. 4, c. 1.