Reed, J.
Defendant’s principal place of business is at Indianapolis, in the state of Indiana, and the transaction out of which this cause arose was had at that j>lace. Plaintiff visited Indianapolis for the purpose of purchasing the necessary machinery for a mill which the Grundy County Mill Company was building, and he entered into a negotiation with defendant, which resulted in the purchase of said machinery from it. Defendant is a corporation, and the negotiation was conducted on its part principally by one Dwyer, who was in its employ as draughtsman and superintendent of its shop. Plaintiff’s claim is that Dwyer agreed that defendant would pay him a commission on the purchase in case it should be consummated; also that defendant subsequently ratified this contract, and performed it in part by paying him a portion of said commission.
*473i assignrorf^must" he specific. It is urged by appellant’s counsel in argument (1) that the evidence does not establish that Dwyer ever assumed to make ^ie aUege(l contract; and (2) that it does not show a subsequent ratification of such contract py defendant. The question of the sufficiency of tlie evidence to. sustain the verdict was raised in the circuit court by the motion for a new trial, but was not raised in any other manner. Appellant seeks to raise the question in this court by assigning as error the ruling on this motion. The assignment of error is in the following form: “The court erred in overruling the motion for a new’ trial.” The motion, however, alleged some eight other grounds on which a new trial was demanded, some of which have been urged in this court, while others were not referred to by counsel in argument. "We cannot consider this assignment, or determine any question which has been presented in argument under it, but which is not otherwise raised.
It is provided by section 3207 of the Code that “ an assignment of error * * * must, in a way as specific as the case will allow, point out the very error objected to. Among several points in a demurrer or in a motion or instructions, * * * it must designate which is relied on as error, and the court will only regard errors which are assigned with the required exactness.” It is clear that this assignment does not comply with this requirement. If we could consider the question of the sufficiency of the evidence to sustain the verdict under it, we might also consider any one of the other questions raised by the motion for a new trial. But it does not specifically point out the ruling on any of these questions as erroneous. Our uniform holding heretofore has been that assignments of error in this form should be disregarded. Bardwell v. Clare, 47 Iowa, 297; McCormick v. Railroad Co., Id., 345; Terry v. Taylor, 64 Id., 35.
*4742. cobpokaon parofto prove agency and nature of agent’s duties*473II: Plaintiff was examined as a witness in his own behalf, and testified that he knew the relation which Dwyer sustained *474to defendant, and that he was its general business manager. Defendant moved to exclude this . n . evidence on the ground that, as it was a corpora-0 i tion, its record was the best evidence of who were its officers. This motion was overruled, and defendant assigns this ruling as error. If it had been claimed that Dwyer was an officer of the corporation, elected or appointed by the shareholders, the record of their action in electing him would have been the best evidence of his official character; but no such claim was made. Indeed, it was subsequently shown by Dwyer’s own testimony that he was a mere employe of the corporation. The character of his employment and the nature of his duties might be shown, we think, by parol.
3. agent to rigiitafto con tract witlr setter for conmussiou on sale. III. Plaintiff also testified that he made the contract, under which his right to the commission accrued, with Dwyer, and that defendant subsequently ratified the contract and paid him a portion of the commission. He , . , also admitted that at the time he made the contract he was acting as agent for the Grundy County Company in making the purchase. After this admission was made, defendant' moved the court to exclude the evidence with reference to the making of the contract and the payment of the money to plaintiff, on the ground that he could not, while acting as agent for the buyer in the purchase of the property, make a valid contract with the seller for the payment by it of a consideration for his services in effecting the sale. It also asked the court to instruct the jury that a contract by it to pay plaintiff a commission for making the sale of the machinery, when he was acting as the agent of the vendee in making the purchase, would be void. The court overruled the motion to exclude the evidence. It also refused to give the instruction asked, and these rulings are assigned as error. It is a well-settled and salutary rule of law that an agent will not be permitted to put himself, during his agency, in a position which is adverse to that of his principal. If his agency is to sell the property of his *475principal, lie cannot himself be the purchaser. And if it is to purchase for his principal, he cannot be the seller. The rule, however, is for the benefit and protection of the principal, and, as a general rule, he is the only party who can avoid a contract made in violation of it. If he chooses to authorize his agent to transact his business in a manner which the rule, but for such authority, would forbid, or if he subsequently ratifies the contract of his agent, made in violation of it, other parties will not be heard to question it. Jackson v. Van Dalfsen, 5 Johns., 43; Jackson v. Walsh, 14 Id., 407; Litchfield v. Cudworth, 15 Pick., 31.
When defendant entered into the contract it had full knowledge of the relation which existed between plaintiff and the Grundy County Company. It knew that he was acting as the agent of that company in making the purchase of the machinery, yet it contracted to pay him a commission for effecting the sale. The jury have found, at least, that it made such contract. The evidence shows without any conflict that plaintiff’s principal is not only satisfied with the contract, but that it authorized him in advance to contract, in the purchase of the machinery, for the payment by the seller of such a commission on the sale as would compensate him for his services in transacting the business. As the contract was entered into by plaintiff by the authority of his principal, and as defendant contracted with him with knowledge of his relation to his principal, it is very clear, we think, that it cannot now avoid its undertaking. Plaintiff in the transaction acted to some extent as the agent of both defendant and the Grundy County Company, but each consented that he might act in that capacity for the other, and what was done in the transaction was done with the consent of both principals. There was therefore no element of illegality in the contract, and no rights of either of the parties were violated in making it. The rulings of the circuit court in overruling the motion to exclude the evidence, and in refusing to give the instructions asked, were therefore correct.
*4764 iNSTituewithoutrprejudice. The court, however, did give the following instruction: “ You will in no event find for the plaintiff on the contract claimed, if you find that at the time of making sa^ contract he was employed by the Grundy County Mill Conrpany, and was acting as its agent in the transaction, with full power from it to purchase in the general market the property or furnishings bought of the defendant; but in the event you find that the plaintiff was so acting with said authority by the mill company, you will find for the defendant."’ Defendant excepts to that portion of the instruction which holds that the contract would be rendered invalid by the fact of plaintiff’s agency for the Grundy County Company only in case he had full power by virtue of this agency to purchase in the general market. .As we have held that under the undisputed evidence the contract was not rendered invalid by the fact that plaintiff was acting as the agent of the mill company in making the purchase, it is unnecessary for us to inquire whether this limitation expresses a correct rule or not. The instruction should not have been given, but defendant was not prejudiced by it.
s pleading • améndment: statements: practice. IY. The court instructed the jury that plaintiff could not recover unless he had proven either (1) that defendant had conferred upon Dwyer authority to make the contract under which he claimed; or (2) that the power to make it was a necessary incident to the transac(¿on 0f tn-angh 0f defendant’s business which Dwyer was authorized to transact; or (3) that the contract had been subsequently ratified by defendant. In his original petition plaintiff alleged generally that the contract on which he sought to recover was entered into between him and defendant. In an amendment filed during the progress of the trial he alleged that the contract was made by Dwyer, who assumed to act as agent for defendant, and that defendant had subsequently ratified it.
Appellant now contends that the only question presented by the pleadings was whether Dwyer had assumed to make a *477contract for tlie payment of said commission, which it had subsequently ratified, and that the court erred in submitting to the jury the question whether Dwyer had original authority to make the contract. ¥e think, however, that this position is not correct. • The allegations of the original petition were not withdrawn. The pleading as amended alleged a contract made with defendant. It also alleged one made with defendant’s agent, and which it had ratified. Plaintiff could have been required by proper proceeding to elect on which allegation he would rely, or to set out the different states of facts pleaded in different counts of his petition; but this was not done. The cause was tried upon a pleading in which both states of facts were alleged, and were pleaded in a single count. The allegation that the contract was entered into with defendant would be sujrported by proof that it was made by an agent who had authority to make it, and the court, we think, did not err in submitting that question to the jury.
¥e have examined the questions presented by counsel, and we find no ground for disturbing the judgment.
Affirmed.