in the Law of England, a voluntary or verbal promise, whereby a person assumes, or takes upon him to perform or pay any thing to another.

A promise is in the nature of a verbal covenant, and wants nothing but the solemnity of writing and feeling to make it absolutely the fame. If therefore it be to do any explicit act, it is an express contract, as much as any covenant; and the breach of it is an equal injury. The remedy indeed is not exactly the fame: since, instead of an action of covenant, there only lies an action upon the case, for what is called an assumpsit or undertaking of the defendant; the failure of performing which is the wrong or injury done to the plaintiff, the damages whereof a jury are to estimate and settle. As, if a builder promises, undertakes, or assumes to Caius, that he will build and cover his house within a time limited, and fails to do it; Caius has an action on the case against the builder for this breach of his express promise, undertaking, or assumpsit; and shall recover a pecuniary satisfaction for the injury sustained by such delay. So also in the case of a debt by simple contract; if the debtor promises to pay it and does not, this breach of promise entitles the creditor to his action on the case, instead of being driven to an action of debt. Thus likewise a promissory note, or note of hand not under seal, to pay money at a day certain, is an express assumpsit; and the payee at common law, or by custom and act of parliament the indorsee, may recover the value of the note in damage, if it remains unpaid. Some agreements indeed, though never so expressly made, are deemed of so important a nature, that they ought not to rest in verbal promise only, which cannot be proved but by the memory (which sometimes will induce the perjury) of witnesses. To prevent which, the statute of frauds and perjuries, 29 Car. II. c. 3. enacts, that in the five following cases no verbal promise shall be sufficient to ground an action upon, but at the least some note or memorandum of it shall be made in writing, and signed by the party to be charged there with: 1. Where an executor or administrator promises to answer damages out of his own estate. 2. Where a man undertakes to answer for the debt, default, or miscarriage, of another. 3. Where any agreement is made upon consideration of marriage. 4. Where any contract or sale is made of lands, tenements, or hereditaments, or any interest therein. 5. And lastly, where there is any agreement that is not to be performed within a year from the making thereof. In all these cases a mere verbal assumpsit is void.

From these express contracts the transition is easy to those that are only implied by law. Which are such as reason and justice dictate, and which therefore the law presumes that every man has contracted to perform; and, upon this presumption, makes him answerable to such persons as suffer by his non-performance.

Thus, 1. If I employ a person to transact any business for me, or perform any work, the law implies that I undertook, or assumed, to pay him so much as his labour deserved; and if I neglect to make him amends, he has a remedy for his injury by bringing his action on the case upon this implied assumpsit: wherein he is Assumptit. at liberty to suggest that I promised to pay him so much as he reasonably deserved, and then to aver that his trouble was really worth such a particular sum, which the defendant has omitted to pay. But this valuation of his trouble is submitted to the determination of a jury; who will assess such a sum in damages as they think he really merited. 'This is called an assumptit on a quantum meruit.

2. There is also an implied assumptit on a quantum valebat, which is very similar to the former; being only where one takes up goods or wares of a tradesman, without expressly agreeing for the price. There the law concludes, that both parties did intentionally agree that the real value of the goods should be paid; and an action on the case may be brought accordingly, if the vendee refuses to pay that value.

3. A third species of implied assumptit is when one has had and received money belonging to another without any valuable consideration given on the receiver's part; for the law confines this to be money had and received for the use of the owner only; and implies that the person receiving, promised and undertook to account for it to the true proprietor. And, if he unjustly detains it, an action on the case lies against him for the breach of such implied promise and undertaking; and he will be made to repair the owner in damages, equivalent to what he has detained in such violation of his promise. This is a very extensive and beneficial remedy, applicable to almost every case where the defendant has received money which ex aequo et bono he ought to refund. It lies for money paid by mistake, or on a consideration which happens to fail, or through imposition, extortion, or oppression, or where undue advantage is taken of the plaintiff's situation.

4. Where a person has laid out and expended his own money for the use of another at his request, the law implies a promise of repayment, and an action will lie on this assumptit.

5. Likewise, fifthly, upon a stated account between two merchants, or other persons, the law implies that he against whom the balance appears has engaged to pay to the other; though there be not any actual promise. And from this implication it is frequent for actions on the case to be brought, declaring that the plaintiff and defendant had settled their accounts together, insuffit computatit (which gives name to this species of assumptit); and that the defendant engaged to pay the plaintiff the balance, but has since neglected to do it. But if no account has been made up, then the legal remedy is by bringing a writ of account, de computo; commanding the defendant to render a just account to the plaintiff, or show the court good cause to the contrary. In this action, if the plaintiff succeeds, there are two judgments; the first is, that the defendant do account (quod computet) before auditors appointed by the court; and when such account is finished, then the second judgment is, that he do pay the plaintiff so much as he is found in arrear.

6. The last class of contracts, implied by reason and construction of law, arises upon this supposition, that every one who undertakes any office, employment, trust, or duty, contracts with those who employ or intrust him, to perform it with integrity, diligence, and skill: and if by his want of either of those qualities any injury accrues to individuals, they have therefore their remedy in damages by a special action on the case. A few instances will fully illustrate this matter. If an officer of the public is guilty of neglect of duty, or a palpable breach of it, of non-feasance, or of mis-feasance; as, if the sheriff does not execute a writ sent to him, or if he wilfully makes a false return thereof; in both these cases the party aggrieved shall have an action on the case for damages to be assessed by a jury. If a sheriff or gaoler suffers a prisoner who is taken upon mesne process (that is, during the pendency of a suit) to escape, he is liable to an action on the case. But if, after judgment, a gaoler or a sheriff permits a debtor to escape, who is charged in execution for a certain sum; the debt immediately becomes his own, and he is compellable by action of debt, being for a sum liquidated and ascertained, to satisfy the creditor in his whole demand. An advocate or attorney that betray the cause of their client, or, being retained, neglect to appear at the trial, by which the cause miscarries, are liable to an action on the case, for a reparation to their injured client. There is also in law always an implied contract with a common innkeeper, to secure his guest's goods in his inn; with a common carrier or barge-master, to be answerable for the goods he carries; with a common farrier, that he shoes a horse well, without laming him; with a common taylor, or other workman, that he performs his business in a workmanlike manner: in which if they fail, an action on the case lies to recover damages for such breach of their general undertaking. Also, if an innkeeper, or other victualler, hangs out a sign and opens his house for travellers, it is an implied engagement to entertain all persons who travel that way; and upon this universal assumptit an action on the case will lie against him for damages, if he without good reason refuses to admit a traveller. In contracts likewise for sales, if the seller doth upon the sale warrant it to be good, the law annexes a tacit contract to this warranty, that if it be not so, he shall make compensation to the buyer; else it is an injury to good faith, for which an action on the case will lie to recover damages.