It is contended by the plaintiff, that the trustee discloses no assignment of the lease of Twitcheli; that the lease, being under seal, cannot be assigned, except by an instrument of like character; and that the delivery, in this case, was nothing but a bare authority to collect the rent; and he relies on the cases of Foster v. Sinkler, 4 Mass. 450, and Wood v. Partridge, 11 Mass. 488, to support his positions.

As to the first objection, it was, as the plaintiff argues, formerly held that, unless the trustee disclosed the assignment in his answer, the assignee could not avail himself of his assignment. But the law is now altered by the revised statutes, for the purpose of enabling an assignee to come in and enforce his rights. Rev. Sts. c. 109, <§> 15. This section provides that, while the answer of the trustee shall be considered as true in deciding how far he is chargeable, yet that “ either party may allege and prove any other facts, not stated nor denied by the supposed trustee, that may be material in deciding that question.” And § 17 provides that “if it shall appear that any goods, effects or credits, in the hands of any supposed trustee, are claimed by any other person, by force of an assignment from the principal defendant, or otherwise, the court may permit such claimant to appear,” <fcc. This section was a revision of St. 1817, c. 148, § 1, which enacted “ that, when any person summoned as a trustee of any debtor shall, in his answer, disclose an assignment to another,” &c. And the object of the alteration, in omitting the words “ in his answer,” was to enlarge the rights of the parties, and to authorize the proof of facts not within the knowledge of the trustee, as appears by the notes of the commissioners to § 15 of c. 109, in which they refer to the decisions in the cases above cited, as showing the necessity of an alteration in the law. This objection, therefore, cannot avail the plaintiff.

As it regards a legal assignment of the claim in question, the authorities cited by the plaintiff’s counsel are in point. But this court have long since recognized the doctrine of *184equitable assignments, where there has been a transfer of a chose in action for a valuable consideration, and a promise by the debtor to pay to the holder, upon knowledge of the transfer. The leading case is Mowry v. Todd, 12 Mass. 281, in which the court held that where a written contract, signed by the defendant in favor of a third person, was delivered by such third person to the plaintiff for a valuable consideration, with a knowledge of the fact on the part of the defendant, and a promise by him to pay the holder, an action might be maintained by the plaintiff, in his own name, founded on such transfer and the promise of the debtor to pay him ; the court considering it the substitution of one creditor for another, by the consent of the creditor and the debtor. This was followed by the case of Jones v. Witter, 13 Mass. 304, where the court held that the assignment might as well be proved by witnesses, as by the name of the payee on the back of the paper; and that the assignment was executed by the delivery of the contract. The case of Dunn v. Snell, 15 Mass. 481, was that of a valuable consideration paid for a judgment, and an agreement to assign the same, but of which no written transfer was in fact made; and it was held that there was an equitable interest vested in the creditor, which the court would protect. See also Crocker v. Whitney, 10 Mass. 316. Similar decisions have been made in the State of New York. See Canfield v. Monger, 12 Johns. 346. Dawson v. Coles, 16 Johns. 51. Briggs v. Dorr, 19 Johns. 95.

In view of these decisions, we are of opinion that the delivery to Brooks of the lease, on which rent was due, to enable him to receive the same in part payment of a debt due to him, with the knowledge of the lessee of its delivery for that purpose, and an agreement on his part to account to Brooks for the rent remaining due on the lease, was a good equitable assignment of the rent, and that the same is not subject to the trustee process of the plaintiff, as the property of Twitchell. In this decision, we have no reference to any supposed right of Brooks, as assignee of the mortgage, to *185claim the rent. We now view him and the party claiming under him only in the light of an equitable assignee.

The exceptions are sustained, the verdict is set aside, and a new trial is to be had at the bar of this court.