Hill, J.
(After stating the foregoing facts.)
1. The petition in this case sets forth a cause for action, and the demurrer was properly overruled. We do not think the contract sued upon is open to the objection urged, that it is unilateral and not binding on Davison & Fargo. .As between Davison & Fargo and Dozier, the latter could waive the fact that his agents did not sell his cotton alone. Davison & Fargo had sold to Heineken & Vogelsang 728 bales of cotton, and through his agents, Davison & Fargo, upon a consideration of one dollar per bale, the work done, and the obligations assumed by the agents, Dozier had sold to Heineken & Vogelsang 100 bales of cotton, which the agents were to deliver on the contract. Dozier, the principal, agreed with his agents, Davison & Fargo, that he would stand back of them and make good their losses by reason of any failure on his part to deliver the 100 bales of cotton. That makes a contract between Dozier, the principal, and Davison & Fargo, his agents, for that purpose. If the agents perform their part of the contract and suffer loss, the principal, under the terms of his contract, is bound by it. Such a contract is not unilateral, but is a valid, binding contract, and the agents are entitled to reimbursement if they suffer loss; and this regardless of the contract with Heineken & Vogelsang. Between the principal and the agent, the former can not repudiate his contract with the latter. It is a question between Dozier and his agents, Davison & Fargo, as to what he did with his cotton. He ratified his agents’ action, and said, in effect, '‘‘You go ahead and incur certain liabilities and I will protect and *194hold you harmless for any loss by reason of such agreement.” The plaintiff in error insists that he did not authorize his agents to put his cotton in with the 728 bales to be delivered to Heineken & Vogelsang; but after his agents had done that, Dozier signed another contract and delivered part of the cotton, and thus ratified the' contract of September 4th. The defendant did not deliver all of his cotton according to contract, and his agents, Davison & Fargo, had to go into the open market and buy 63 bales of cotton at the advanced market price of 14-3/4 cents per pound; and under the terms of his agreement, Dozier is bound by it to make good any loss sustained by his agents, Davison & Fargo. This is not a sale of cotton by the defendant, Dozier, to his agents Davison & Fargo. It is a case of agency, and a guaranty by the principal to his agents that he will make good any loss they may sustain on his account by reason of his failure to deliver the 100 bales of cotton according to contract. And Dozier is responsible to his agents, Davison & Fargo, if they sustained loss, regardless of how the contract stood between Dozier and I-Ieineken & Vogelsang. The evidence shows that the defendant’s agents did sell for him 100 bales of cotton at 12.53 cents per pound, and that he delivered to them only 37 bales, and that they had to go into the market and buy 63 bales; and the plaintiffs testified that “by having to supply that cotton we lost the amount set out in the petition.”
Again, the defendant insists that the plaintiffs can not recover, because the 37 bales of cotton were not paid for when delivered by the defendant. The reply is that the evidence shows that the defendant was to get pay for the cotton when he delivered all the cotton due’ on the contract, namely, 100 bales. In point of fact, a portion of the money was paid the defendant soon after the cotton was delivered, but the contract was for the delivery of 100 bales of cotton, and the defendant can not complain that payment was deferred until the entire 100 bales were delivered; and any verbal agreement as to payment, which varies' the plain, unambiguous written contract, under the facts of this case, is not admissible to change or modify the written contract. Forsyth Mfg. Co. v. Castlen, 112 Ga. 199 (37 S. E. 485, 81 Am. St. R. 28); Hawkins v. Studdard, 132 Ga. 265 (63 S. E. 852, 131 Am. St. R. 190).
2. The fourth paragraph of the defendant’s plea was properly *195stricken on motion. This answer was clearly an effort to set up a parol contract which varied the terms of the written contract executed by the parties, and which was plain and unambiguous within itself. This plea seeks to vary the plain terms of the written contract, and undertakes to substitute an entirely different one, which can not be done. The stricken plea avers, among other things, that the cotton was not to be delivered under the sale already made, but was to be “sold on delivery and sales- and remittances made promptly as rapidly as sold.” Even if it was error to strike the above-stated plea, it did not cause-injury to the defendant, as the cotton delivered was paid for by the plaintiffs, except the small sum of $3.43, before the entire 100 bales were delivered; and there is no evidence in the record to show that Davison & Fargo.failed to properly grade, weigh, and pay for the cotton actually delivered, other than as to the payment of the small amount above referred to, and certainly the defendant could not be entitled to variations on that not delivered.
3. It follows from what has been said in the foregoing division of this opinion, that if the fourth paragraph of the defendant’s answer was properly stricken, the evidence sought to be introduced under it was properly excluded by the court. Civil Code (1910), § 4268, par. 1; Hawkins v. Studdard, supra; Burton v. Meinert, 136 Ga. 420 (71 S. E. 870).
4. There is no error in any of the other grounds of the motion requiring a new trial. The evidence authorized the direction of the verdict rendered in-favor of the plaintiffs.
Judgment affirmed.
All the Justices concur.