If the assignment to the plaintiff of the contract sued on was valid, the plaintiff is the real party in interest, and as such entitled, under the practice in Colorado, to maintain this action in its own name. Rev. St. § 914; Code Civil Proc. Colo. § 3; Steel Co. v. Lundberg, 121 U. S. 451, 7 Sup. Ct. Rep. 958. The vital question in the case, therefore, is whether the contract between the defendant and Billing & Eilers was assignable by the latter, under the circumstances stated in the complaint. At the present day, no doubt, an agreement to pay money, or to deliver goods, may be assigned by the person to whom the money is to be paid or the goods are to be delivered, if there is nothing in the terms of the contract, whether by requiring something to be afterwards done by him, or by some others tipulation, which manifests the intention of the parties that it shall not be assignable. But every one has a right to select and determine with whom he will contract, and cannot have another person thrust upon him without his consent. In the familiar phrase of Lord DENMAN, 'You have the right to the benefit you anticipate from the character, credit, and substance of the party with whom you contract.' Humble v. Hunter, 12 Q. B. 310, 317; Winchester v. Howard, 97 Mass. 303, 305; Ice Co. v. Potter, 123 Mass. 28; King v. Batterson, 13 R. I. 117, 120; Lansden v. McCarthy, 45 Mo. 106. The rule upon this subject, as applicable to the case at bar, is well expressed in a recent English treatise: 'Rights arising out of contract cannot be transferred if they are coupled with liabilities, or if they involve a relation of personal confidence such that the party whose agreement conferred those rights must have intended them to be exercised only by him in whom he actually confided.' Pol. Cont. (4th Ed.) 425. The contract here sued on was one by which the defendant agreed to deliver 10,000 tons of lead ore from its mines to Billing & Eilers at their smelting works. The ore was to be delivered at the rate of 50 tons a day, and it was expressly agreed that it should become the property of Billing & Eilers as soon as delivered. The price was not fixed by the contract, or payable upon the delivery of the ore. But, as often as a hundred tons of ore had been delivered, the ore was to be assayed by the parties or one of them, and, if they could not agree, by an umpire; and it was only after all this had been done, and according to the result of the assay, and the proportions of lead, silver, silica, and iron thereby proved to be in the ore, that the price was to be ascertained and paid. During the time that must elapse between the delivery of the ore and the ascertainment and payment of the price the defendant had no security for its payment, except in the character and solvency of Billing & Eilers. The defendant, therefore, could not be compelled to accept the liability of any other person or corporation as a substitute for the liability of those with whom it had contracted. The fact that upon the dissolution of the firm of Billing & Eilers, and the transfer by Eilers to Billing of this contract, together with the smelting works and business of the partnership, the defendant continued to deliver ore to Billing according to the contract, did not oblige the defendant to deliver ore to a stranger, to whom Billing had undertaken, without the defendant's consent, to assign the contract. The change in a partnership by the coming in or the withdrawal of a partner might perhaps be held to be within the contemplation of the parties originally contracting; but, however that may be, an assent to such a change in the one party cannot estop the other to deny the validity of a subsequent assignment of the whole contract to a stranger. The technical rule of law, recognized in Murray v. Harway, 56 N. Y. 337, cited for the plaintiff, by which a lessee's express covenant not to assign has been held to be wholly determined by one assignment with the lessor's consent, has no application to this case. The cause of action set forth in the complaint is not for any failure to deliver ore to Billing before his assignment to the plaintiff, (which might perhaps be an assignable chose in action,) but it is for a refusal to deliver ore to the plaintiff since this assignment. Performance and readiness to perform by the plaintiff and its assignors, during the periods for which they respectively held the contract, is all that is alleged; there is no allegation that Billing is ready to pay for any ore delivered to the plaintiff. In short, the plaintiff undertakes to step into the shoes of Billing, and to substitute its liability for his. The defendant had a perfect right to decline to assent to this, and to refuse to recognize a party, with whom it had nevr contracted, as entitled to demand further deliveries of ore. The cases cited in the careful brief of the plaintiff's counsel, as tending to support this action, are distinguishable from the case at bar, and the principal ones may be classified as follows: First. Cases of agreements to sell and deliver goods for a fixed price, payable in cash on delivery, in which the owner would receive the price at the time of parting with his property, nothing further would remain to be done by the purchaser, and the rights of the seller could not be affected by the question whether the price was paid by the person with whom he originally contracted or by an assignee. Sears v. Conover, *42 N. Y. 113, 4 Abb. Dec. 179; Tyler v. Barrows, 6 Rob. (N. Y.) 104. Second. Cases upon the question how far executors succeed to rights and liabilities under a contract of their testator. Hambly v. Trott, Cowp. 371, 375; Wentworth v. Cock, 10 Adol. & E. 42, 2 Perry & D. 251; 3 Williams, Ex'rs (7th Ed.) 1723-1725. Assignment by operation of law, as in the case of an executor, is quite different from assignment by act of the party; and the one might be held to have been in the contemplation of the parties to this contract, although the other was not. A lease, for instance, even if containing an express covenant against assignment by the lessee, passes to his executor. And it is by no means clear that an executor would be bound to perform, or would be entitled to the benefit of, such a contract as that now in question. Dickinson v. Calahan, 19 Pa. St. 227. Third. Cases of assignments by contractors for public works, in which the contracts, and the statutes under which they were made, were held to permit all persons to bid for the contracts, and to execute them through third persons. Taylor v. Palmer, 31 Cal. 240, 247; St. Louis v. Clemens, 42 Mo. 69; Philadelphia v. Lockhardt, 73 Pa. St. 211; Devlin v. New York, 63 N. Y. 8. Fourth. Other cases of contracts assigned by the party who was to do certain work, not by the party who was to pay for it, and in which the question was whether the work was of such a nature that it was intended to be performed by the original contractor only. Robson v. Drummond, 2 Barn. & Adol. 303; Waggon Co. v. Lea, 5 Q. B. Div. 149; Parsons v. Woodward, 22 N. J. Law, 196. Without considering whether all the cases cited were well decided, it is sufficient to say that none of them can control the decision of the present case. Judgment affirmed.