Set-off should, however, be discriminated from reduction and recoupment; to both of which it bears much analogy, and with either of which it may be so mingled by the facts of a case as to make it difficult to say in which of these forms the opposing demand should be brought against the plaintiff's action. In general, a defendant may deduct from the plaintiff's claim all just demands or claims the statute before cited, that a set-off is allowed in cases of mutual debts, i. e., claims in the nature of a debt; and the same rule is applied to both parties. For if the suit is brought, not for a debt, but for unliquidated damages, no defence of set-off can be allowed. Hardcastle v. Netherwood, 6 B. & Ald. 93, which was an action for not indemnifying the plaintiff for paying the defendant's own proper debt; Hutchinson v. Reid, 3 Camp. 829, for not accepting a bill of exchange; Birch v. Depeyster, 4 Camp. 385, against an agent for not accounting; Gillingham v. Waskett, 18 Price, 484, for not replacing stock according to agreement; Warn v. Bickford, 7 Price, 650, for breach of a covenant for quiet enjoyment; Attwool v. Attwool, 1 Ellis & B. 21, 18 Eng. L. & Eq. 386, for breach of a bond to idemnify generally; Castelli v. Boddington, 1 Ellis & B. 66; 16 Eng. L. & Eq. 127, an action on a policy of insurance for an average loss. And see Cope v. Joseph, 9 Price, 155; Gordon v. Bowne. 2 Johns. 150; Osborn v. Etheridge, 18 Wend. 339, a suit by a tenant against his landlord, to recover costs of the defence of summary proceedings, instituted by the latter; Cooper v. Robinson, 2 Chitty, 161, for not indemnifying plaintiff from certain taxes; Wilmot v. Hurd, 11 Wend. 584, for breach of warranty in the sale of goods; Dowd v. Faucett, 4 Dev. 92, covenant for uncertain damages. And see further, Pettee v. The Tennessee Manufacturing Co. 1 Sneed, 385; Edington v. Pickle, id. 122. More frequent illustrations exist of claims which cannot be used by a defendant by way of set-off, because they are not debts within the statutory meaning of that word. Thus, it seems that unliquidated losses on a policy of insurance cannot be made the subject of set-off. Thomson v. Redman, 11 M. & W. 487; Grant v. Royal Exch. Ass. Co. 5 M. & S. 439. And see Cumming v. Forester, 1 id. 494. Nor can a claim for tortiously taking the defendant's property be set off. Hopkins v. Megquire, 85 Me. 78. Neither is a breach of a covenant for the nondelivery of goods according to contract a subject of set-off. Howlet v. Strickland, Cowp. 56; Wright v. Smyth, 4 Watts & 8. 527. Nor a breach of the guaranty when the damages are uncertain. Moreley v. Inglis, 4 Bing. N. C. 58; Crawford v. Stirling, 4 Esp. 207. Contra, if the damages are certain. Collins v. Wallis, 15 J. B. Moore, 248. 8o, to an action by a bank, the defendant cannot set off his stock in the bank. Harper v. Calhoun, 7 How. Miss. 203; Whittington v. Farmers Bank, 5 Harris & J. 489. Nor can he set off the bills of such bank. Hallowell Bank v. Howard, 13 Mass. 235. A note payable in work cannot be set off against a demand payable in cash. Brather v. McEvoy, 7 Mo. 598. In Massachusetts taxes are not the subject of set-off. Peirce v. Boston. 8 Met. 520.

(d) As to the right of the defendant to reduce the plaintiff's demand in the cases mentioned, ante, p. •523, n. (i), see the following cases: Hasten v. Butter, 7 East, 679; Farnsworth v. Garrard, 1 Camp. 88 ; Denew v. Daverell, 3 id. 451; Mandel v. Steel, 8 M. & W. 868; Heck v. Shener, 4 S. & R. 249; Still v. Hall, 20 Wend. 51; Hunt v. The Otis Company, 4 Met. 464; McAllister v. Reab, 4 Wend. 483, 8 id. 109; Britton v. Turner, 6 N. H. 481.

(e) The difference between allowing a certain defence by way of set-off, and by way of reduction of damages, although not broad, is yet clear and well-defined. A few instances will illustrate the application of the principle. Thus, in assumpsit for dyeing goods, the defendant may, at common law, show that there is a custom of the trade by which damages done the goods in dyeing shall be deducted from the price of dyeing. Barnford v. Harris, 1 Stark. 343. So a master may show, in an action by a servant for his wages, that the plaintiff agreed to deduct therefrom the value of goods lost by his negligence. Le Loir v. Bristow, 4 Camp. 134. And see Dobson v. Lockhart, 6 T. R. 133; Kinnerley v. Hossack, 2 Taunt 170; Cleworth v. Pickford, 7 M. & W. 314. So, in an action for work and labor and materials, the defendant may show, without pleading any set-off, that he supplied part of the materials himself. Newton v. Forster, 12 M. & W. 772; Turner v. Diaper, 2 Man. & G. 241. And see Dale v. Soilet, 4 Burr. 2133, and Lufburrow v. Henderson, 30 Ga. 482; Eddy v. Clement, 38 Vt. 486; Cage v. Phillips, 38 Ala. 637; Phelps v. Paris, 39 Vt. 511; Bates v. Cartwright, 86 Ill. 581; Miller v. Gaither, 3 Bush, 162; King v. Bradley, 44 Ill. 342.

(f) The doctrine of recoupment, or recouper, as it was formerly termed, is not a new one in the common law, although it was formerly used in a different sense from that alluded to in the text. It was formerly used to signify, as it is now in many courts and decisions, a right of deduction from the amount of the plaintiff's claim, either from part payment, or defective performance of contract on the part of the plaintiff, or from any analogous fact. The same idea was expressed by defalk, discount, deduction, reduction, and in actions of tort, by mitigation. But we have given the definition of the text as the true and proper one, since the word recouper in the original signifies to cut again, and therefore would favor the definition above, and Barbour on Set-off is in favor of the same use of the term.

1 Thus, in an action upon a promissory note given in payment for land conveyed with covenant against incumbrance, the defendant can recoup what he has been obliged to pay to free the land from incumbrance. Davis v. Bean, 114 Mass. 358. In Waterman v. Clark, 76 Ill. 428, it is laid down that in recoupment a claim originating in contract may be set up against one founded on tort, and vice versa; but the defendant cannot, as in set-off, recover any excess in his favor.