delivered the opinion of the court.
The statement in the brief of counsel for defendant “that there were allegations in the complaint and evidence before the jury which would sustain a finding that services had been rendered, and that there was no specific or enforceable agreement as to the amount, thus entitling plaintiffs to recover on a quantum meruit,” renders it unnecessary for this court to consider the motion of defendant for a directed verdict, and brings us to the matter of the instructions assigned as error.
Taking the allegations in the complaint as to the agreement for adding to the purchase price and dividing the amount that the price was to be enhanced for their compensation, together with the testimony of plaintiffs themselves, it is clear that it was according to their statement, a matter of speculation, and it was expected by the parties that they would be able to sell the land for an enhanced price, and in that way realize their compensation or commission for making the deal. The testimony of plaintiffs themselves clearly shows that, in so far as a fixed amount of commission is concerned, it was conditioned upon their ability, after taking the option, to make a sale of the timber lands at an enhanced price, and as the agreement for a fixed amount of compensation or commission- was not sustained by any evidence, but was repudiated by plaintiffs, they must recover, if at all, upon a quantum meruit: Gollnick v. Marvin, 60 Or. 312 (118 Pac. 1016), decided November 14, 1911. In other words, in order for plaintiffs to recover on an express contract for a fixed compensation under the pleadings and evidence, giving the plaintiffs the most favorable view thereof, it would be necessary for the plaintiffs to show that a sale of the land was made, or could have been made, at an enhanced price over that named in the option.
*3241. If it be conceded that there were duplicate statements of the same cause of action, or statements of different grounds of recovery contained in the complaint, the defendant was entitled, on motion therefor, at any time before or during the progress of the trial, to have the plaintiff elect upon which ground or cause he would proceed. Harvey v. Southern Pac., 46 Or. 505, 510 (80 Pac. 1061), quoting Pomeroy Code Rem. (4 ed.) §§ 467, 576. In this case, however, such motion was unnecessary, as the plaintiffs’ counsel plainly indicated upon which ground he would porceed. The claim of plaintiffs seems to be that, by reason of the defendant’s abandoning the arrangement to sell the land at an enhanced price, and purchasing it himself, thereby receiving the benefit of plaintiffs’ services, they were entitled to a reasonable compensation therefor. It is a rule of pleading that a complaint must proceed upon some definite theory, and on that theory the plaintiff must recover, if at all. Mescall v. Tully, 91 Ind. 96; Cottrell v. Aetna Life Insurance Co., 97 Ind. 311.
2. Counsel for defendant contend that plaintiffs are bound by the declaration made in court as to the nature of the liability upon which they seek to recover, and that the matter of the reasonable value of plaintiffs’ services should have been submitted to the jury, and that it was error to instruct the jury that the plaintiffs’ claim was for services upon an agreed compensation. We think the point is well taken. The testimony varied as to the amount upon which to base the commission, or as to the reasonable value of the services alleged to have been rendered by plaintiffs, and this question was not submitted to the jury. It was possible under the evidence, had the matter been so submitted, for the jury to have found a verdict at least $1,761 less than the amount of the judgment, after deducting the amount remitted by plaintiffs. Barnes v. Quigley, 59 N. Y. 265. A verdict *325of $16,666.67 was returned, and afterwards plaintiffs filed a remittitur for the excess over $10,507.48, the amount demanded as a reasonable compensation, and judgment was entered for that amount. The judgment, therefore, is based upon a quantum meruit, without that question having been submitted to the jury. Where there is a dispute as to the facts, or if there be no dispute as to the facts, but there may reasonably be a difference of opinion as to the inferences and conclusions deducible therefrom, it is the province of the jury to determine the question. Hedin v. Suburban R. R. Co., 26 Or. 155 (37 Pac. 540); Connell v. McLoughlin, 28 Or. 230 (42 Pac. 218).
Under the Constitution of Oregon (Article I, Section • 17), providing that in all civil cases the right of trial by jury shall remain inviolate, we think the defendant was entitled to have this matter passed upon by a jury (Shobert v. May, 40 Or. 68: 66 Pac. 466: 55 L. R. A. 810: 91 Am. St. Rep. 453: Elder v. Rourke, 27 Or. 363: 41 Pac. 6), and that the trial court erred in giving the instruction excepted to by defendant.
It follows that the judgment of the lower court must be reversed, and the cause remanded for a new trial.
Reversed.