It is generally assumed that "substantial performance" is a term which represents a definite idea and which accordingly can be defined. It has been said that substantial performance exists "if there has been an honest and faithful performance of the contract in its material and substantial parts and no willful departure from or omission of the essential points of the contract."1 Substantial performance is said to exist "where there has been no willful departure from the terms of the contract and no omission in essential points and it has been honestly and faithfully performed in its material and substantial particulars,' and the only variance from strict and literal performance consists of "technical or unimportant omissions or defects."2

18 See ch. LXXXIV.

1 Bloomington Hotel Co. v. Garth-wait, 227 111. 613, 81 N. E. 714.

2 Peterson v. Pusey, 237 111. 204, 86 N. E. 692.

"The equitable doctrine of substantial performance is intended for the protection and relief of those who have faithfully and honestly endeavored to perform their contracts in all material and substantial particulars, so that their right to compensation may not be forfeited by reason of mere technical, inadvertent, or unimportant omissions or defects. It is incumbent on him who invokes this protection to present a case in which there has been no willful omission or departure from the terms of his contract. If he fails to do so, the question of substantial performance should not be submitted to the jury." Gillespie Tool Co. v. Wilson, 123 Pa. St. 19 [quoted in Morgan v. Gamble, 230 Pa. St. 166, 79 Atl. 410].

"The proper rule is stated in Ashland L., S. & C. Co. v. Shores, 106 Wis. 122, 81 N. W. 136, in effect, thus:

It is said to be unsafe to submit a case of substantial performance to a jury without defining the term "substantial performance." 3

When a contract has not been fully, but has been substantially, performed, in that it has been in good faith complied with in all essentials to the full accomplishment of that which was contracted for (Manitowoc Steam Boiler Works v. Manitowoc Glue Co., 120 Wis. 1, 97 N. W. 515), and the contract labor and material wrought into the property of the proprietor has been appropriated to the use intended, such contractor is entitled to recover the contract price, less such deductions therefrom as will make good to the proprietor the imperfections in the work." Manning v. School District, 124 Wis. 84, 102 N. W. 356.

For a discussion of the nature of substantial performance, see Foeller v. Heintz, 137 Wis. 160, 24 L. R. A. (N.S.) 327, 118 N. W. 543.

Substantial performance is said to exist "where the failure is mere inconsiderable incompleteness, and the expense of completion is easy of ascertainment' and also in cases in which the benefits of defective performance have been accepted voluntarily. Manitowoc Steam Boiler Works v. Manitowoc Glue Co., 120 Wis. 1, 07 N. W. 515.

3 Manning v. School District, 124 Wis. 84, 102 N. W. 356.

"The learned court, though using tho term 'substantial performance' many times in the instructions as to each particular feature of the agreement, yet singularly, as we have said, failed entirely to enlighten the jury as to what was meant thereby. That is a very unsafe way to submit a case. It Is very liable to result in the jury not passing upon the vital point at issue. The term 'substantial performance' is by no means without limitation of a legal nature. The rule allowing a recovery on a contract for such performance is equitable in its nature. It is really a judicial invasion of strict contract right out of regard for the contractor who would otherwise, without bad faith, but through mere inadvertence, suffer great or substantial loss, and the proprietor be correspondingly enriched, perhaps obtaining for all practical purposes just what he contracted for. Being a relaxation which modifies the contract without the proprietor's consent, much care should be taken not to permit its abuse to the latter's prejudice, who is entitled, in strict right, to just what he contracted for and in the form agreed upon. To that end the jury should not be left to apply the rule without any guide. They should be instructed that' 'substantial performance' means strict performance in all essentials necessary to the full accomplishment of the purposes for which the thing contracted for was designed. Failure as to any of such features, whether in good faith or bad faith, any departure from the contract, not caused by inadvertence, or unavoidable omission, any defect so essential 'as that the object which the parties intended to accomplish to have a specified amount of work performed in a particular manner is not accomplished,' is inconsistent with substantial performance of the contract. Manitowoc Steam Boiler Works v. Manitowoc Glue Co., 120 Wis. 1, 07 N. W. 515; Woodward v. Fuller, 80 N. Y. 312; Phillips v. Gallant, 62 N. Y. 256. Care should be exercised also to distinguish between that 'substantial performance' enabling the contractor to recover upon the contract, and that other such compliance spoken of in the books, furnishing a basis for relief regardless of the attitude of the proprietor as regards acceptance of the work, so long as he in fact, though unavoidably, has the benefit of what is done. The doctrine that a recovery can be had grounded upon the latter species of substantial performance prevails in many, and perhaps most, jurisdictions at this day. 3 Sutherland, Damages, Sec. 711. It was adopted in Massachusetts as early as 1828 (Hay-ward v. Leonard, 7 Pick. 181), and has been there since firmly adhered to, as the numerous cases found cited in the text in Sutherland show. Authorities in other states that have adopted the same rule are there referred to in connection with the statement that the weight of modern authority is in harmony therewith. However, in this state if there were at any one period, as shown by the, decided cases, some tendency in the same direction, it will be found that for a long period reaching up to the present time the adjudications have been in harmony to the contrary, the most recent cases being Manitowoc Steam Boiler Works v. Manitowoc Glue Co., 120 Wis. 1, 07 N. W. 515, and Sherry v. Madler, 123 Wis. 621, 101 N. W. 1095." Manning T. School District, 124 Wis. 84, 102 N. W. 356.

On the other hand, it has been said that "substantial performance' ' is a term which can not be defined further.4