MARTIN, J.
The facts in this case, so far as relate to the questions presented on this appeal, can be briefly stated. The action was to recover damages for the breach of a contract. The contract as alleged, and found by the jury, was that the plaintiff would transfer to the defendants his farm for the sum of $2,200; that the defendants would sell it to one Olmstead, if possible, and get the highest price they could obtain, and divide equally with the plaintiff any sum they should receive for. it in excess of the price paid. In pursuance of this agreement the plaintiff deeded his farm to the ■defendants, who on the same day sold and conveyed it to Olmstead. The consideration for the last transfer was $2,800, which was paid 'by transferring to the defendants another farm at the agreed price of $1,700, and delivering to them a bond and mortgage for -$1,100. The defendants paid the plaintiff the consideration named in the deed to them, and for certain personal property purchased by them of the plaintiff, but did not pay him any portion of the amount they were to receive for the farm in excess of the price .paid. This action was to recover one-half of the profits arising from such purchase and sale. If the contract between the parties was. valid, the proof was sufficient to sustain the verdict. The farm received from Olmstead in exchange for the one sold1 by the plaintiff has not been sold by the defendants, yet the plaintiff’s proof was that he offered to take the place at the price allowed for it by the defendants, provided they would allow him one-half of the sum that the defendants would thus receive above the $2,200 paid for the plaintiff’s farm, as they agreed, and that the defendants not only refused to allow or pay him that sum, but denied the existence of any such -contract, or any liability on their part to pay the plaintiff any portion of the profits of the transaction. Under these circumstances we are of the opinion that the plaintiff was entitled to maintain this action, provided the contract between the parties can be enforced, and that the .defendants’ motion to dismiss the action because it •was prematurely brought was properly denied.
The most important and the only other question raised on this *377appeal relates to the admissibility of the plaintiff’s evidence to establish the contract between the parties. The appellants claim that parol evidence of the contract made between the parties was inadmissible, because all their preceding negotiations were merged in the deed, and that it tended to contradict or vary its terms. If the deed, between the parties embraced all the agreements and understandings made or had between them, the former negotiations would be merged in it. But the rule that all previous negotiations -or conferences between the parties are merged in a subsequent written instrument is open to qualification. A contract which is not required by statute to be in writing may be partly expressed in writing, and partly by an unwritten understanding between the parties, and, if so, such understanding may be proved by parol. "Where a verbal contract is entire, and a part, only, in part performance, is reduced to writing, paroi proof of the entire contract is competent. Hutchins v. Hebbard, 34 N. Y. 24; Hope v. Balen, 58 N. Y. 380; Brigg v. Hilton, 99 N. Y. 517, 3 N. E. 51. The plaintiff’s proof in this case showed that the whole contract between the plaintiff and defendants was .not reduced to writing, and that the -deed was executed and delivered in part performance, only, of the •entire contract between them. We think this case falls within a qualification of the general rule, and that the court properly admitted the evidence unless the defendants’ claim that it tended to contradict or vary the deed should be sustained. The general rule which excludes parol evidence when offered to contradict or vary the terms, provisions, or legal effect of a written instrument is well settled. There are various cases, however, where this rule does not apply. “It has no application to collateral undertakings,— Lindley v. Lacey, 17 C. B. (N. S.) 578; Jeffery v. Walton, 1 Starkie, 267; Batterman v. Pierce, 3 Hill, 171; Erskine v. Adeane, 8 Ch. App. 756,”—(Engelhorn v. Reitlinger, 122 N. Y. 80, 25 N. E. 297;) or where the written instrument was executed in part performance, only, of •an entire oral agreement, (Chapin v. Dobson, 78 N. Y. 75; Van Brunt v. Day, 81 N. Y. 251; Juillard v. Chaffee, 92 N. Y. 529; Brigg v. Hilton, 99 N. Y. 526, 3 N. E. 51; Ferguson v. Baker, 116 N. Y. 257, 22 N. E. 400; Routledge v. Worthington Co., 119 N. Y. 593, 23 N. E. 1111; Pond v. Harwood, 139 N. Y. 126, 34 N. E. 768.) If the plaintiff’s theory in this case was correct, and the jury has so found, the deed from the plaintiff was not a complete contract embracing all the particulars of the agreement, or designed to express the whole Arrangement between the parties, and the parol evidence given was -consistent with, and not contradictory of, the deed. This case does not, therefore, come within the principle of Thomas v. Scutt, 127 N. Y. 133, 138, 27 N. E. 961, and kindred cases. We are of the opinion that the court properly admitted the parol evidence of the agreement between the parties, and, as no other errors are claimed by the appellants, the judgment should be affirmed. Judgment and order affirmed, with costs. All concur.