delivered the opinion of the Court:
1. It is clear that if the relator has any right át all under the act of August 13, 1894, she has pursued the only remedy open to her, and the question to be determined is, whether, under the facts.stated, that remedy is available.
The first assignment of error, to the effect that the court erred in .holding that the relator is an assignee of the certificates, can not be sustained. Treating the demurrer to the return as reaching back to and raising the question of the sufficiency of the allegations of the petition, we find nothing wanting therein in respect of relator’s right as assignee of Evans through a successive chain of formal transfers. It is true that the assignment to relator bears date after the payment of the judgments of the Court of Claims to the executors of Thomas J. Fisher, to whom Evans had assigned the certificates some time after the passage of the redemption act of June 16, 1880; but this seems to us wholly immaterial. We find nothing in the language of the act of *43August 13, 1894, to justify the contention of the appellant, that the assignees therein “ mean assignees at the time of the redemption, and not any person who, might acquire a general assignment of claims afterwards.” On the other hand, it seems, without doubt, to extend its relief to all owners, holders, or assignees of the certificates that had been redeemed under the act of June 16, 1880, without limitation in respect of the time of the accrual of their respective rights and interests.
Being responsible in case of payment to an unauthorized claimant, the defendant had the right to demand satisfactory proof of the genuineness and regularity of the several assignments under which the relator claimed; and had his denial of payment been founded on the insufficiency thereof, after due inquiry, the writ, of mandarrias would not lie. Had that objection been set up, the relator might have satisfied it by supplementary proofs, or else by proceedings at law for the establishment of her claim as against Evans and intermediate assignees; but it was not raised, either directly or by implication, in the written statement of the grounds upon which the payment was refused.
Nor does the return of the defendant, made to the rule to show cause, deny the genuineness or regularity of the relator’s claim as assignee; hence it must be regarded as admitted.
2. The second contention, namely, “ that the certificates set out in the petition were never redeemed by the treasurer of the United States, and therefore are not certificates within the meaning of the act ” (August 13, 1894), is farfetched and equally untenable with the first one.
The act is general and remedial, and its language affords no ground for saying that the certificates therein referred to as “redeemed” by the treasurer mean such only as had been redeemed in 3.65 bonds under the provisions of the act of June 16, 1880.
We think it apparent that the word “redeemed,” as ap*44plied to said certificates, includes in its meaning not only their redemption in the 3.65 bonds at par as provided in the act of June 16, 1880, but also their payment in cash from the proceeds of such bonds when sold for'the purpose by the treasurer under the supplemental act of March 3, 1881. This act was passed for the benefit of the District, because in the meantime the 3.65 bonds had risen above par in the market. It was to that extent and for that purpose amendatory of the former act and must be considered with it. Any other view would be most unjust as well as unreasonable.
The single purpose of the act of August 13, 1894, was to compensate holders of valid claims, whose payment had been so long delayed, by giving them additional interest, to make up the full legal rate of 6 per cent, for the six years between August 16, 1874—when payment had been suspended—and June 16, 1880, when redemption or payment of the principal with 3.65 per cent, interest was provided for. Moreover, the equities of those who had been paid in cash were even greater than those of certificate holders who had been paid in the bonds, because these latter had received the additional benefit of the immediate advance in the value of those bonds. Furthermore, those redemption acts remained in force, limited in their operation.only by the act of July 5, 1884, providing that no certificate, should be thereafter paid unless presented within one year from this last date.
As a matter of fact, the return made by the defendant in answer to the rule does not set up any such construction of the act of 1894. The sole ground of refusal to pay the demand of relator, as therein stated, is “that these Evans’ certificates ” were not redeemed by him or any person holding the office of treasurer of the United States, and that the only moneys paid by any treasurer, on account of any of the matters or things in the said petition mentioned as having relation to the said certificates, or either of them, were *45paid upon certain judgments of the Court of Claims of the United States as appears by the transcript from the records of the Treasury Department of the United States hereto annexed, and that the defendant has no official knowledge, nor has he any official record in his office showing or tending to show upon what claim or claims said judgments were based.
The undenied allegations of the petition show that the certificates had at last been surrendered, to wit, June 9,1890, upon some agreement of compromise with the District without a judgment. They were immediately presented to the then treasurer, who refused payment. Knowing that the suit was pending upou them in the Court of Claims, he required that they should be reduced to judgments.
When so reduced to judgments and certified to him from the records of that court, be paid the full amounts respectively adjudged, with 3.65 per cent, interest. The certificates became merged in the judgments and were presumably filed with and made a part of the record in the Court of Claims. Hence they could not be paid or redeemed as such; but the payment of the judgments was the complete discharge of their obligation. They were thereby paid, and as completely “redeemed,” in the sense of that word as used in the act of August 13, 1894, as if they had been actually redeemed in bonds under the act of June 16, 1880, without judgment or the necessity of suit.
There is no room for doubt that these judgments were rendered upon the certificates described in the petition, and the defendant does not deny the fact. He simply says that he has no official knowledge and no official record tending to show that such is the fact. The fact is a matter of record in the Court of Claims, and he can readily procure a transcript thereof for his own official files if it be of any real importance. The foregoing being the only defense made in the return, the court did not err in holding it insufficient.
3. The principles which govern the action of the courts *46in the exercise of jurisdiction over the executive departments of the Government have long since been firmly established. Kendall v. Stokes, 12 Pet. 524; Decatur v. Paulding, 14 Pet. 497; U. S. ex rel. Dunlap, v. Black, 128 U. S. 40; Noble v. Union River Logging RR. Co., 147 U. S. 165; Seymour v. South Carolina, 2 App. D. C. 240, 246; Int. Con. Co. v. Lamont, 2 App. D. C. 532, 546; S. C. 155 U. S. 303, 308; Lochren v. Long, 6 App. D. C. 486, 504.
The duty which is sought to be enforced by mandamus must be purely ministerial and existent at the time. The duty of the officer must be plainly defined and one that he is required by the law to perform. In our opinion these requirements are completely satisfied by the conditions of this case. The statute conferring the right and imposing the duty is so plain in its terms as to admit of no room for construction.
The situation is quite different from that, in Decatur v. Paulding, or in United States, ex rel. Dunlap, v. Black, supra, wherein the duty of construing different laws and determining by which one the rights of the relators were to be governed was necessarily involved. Moreover, as we have seen, the defendant did not, in fact, found his refusal to perform upon any such supposed duty of construction of the statute.
4. The further point has been made that the record does not show in whose possession the two certificates were when the suit was filed. Presumably they are on file in the Court of Claims in the records of the suits therein; but at the same time some doubt as to this is raised by certain recitals of the petition. Whilst they are of a nature, especially since their merger in the judgments, that renders their possession of comparative unimportance; yet the defendánt, as a public officer, is entitled to as complete protection from all danger of further litigation as can be afforded by the judgment of the court. Consequently, if these certificates were not surrendered in procuring the judgments upon them, it is but just that the judgment in this case should be so *47amended as to require their surrender to the defendant as a condition precedent to the execution of the writ.
The judgment will be affirmed with costs, and the cause will be remanded with leave to amend that judgment if need be in accordance with the foregoing suggestion.
It has been suggested that this cause be treated as one to which the United States are parties, because of the official character of the defendant, and that, as a consequence, no costs should be awarded.
It is to be regretted that no action has ever been taken by Congress to meet the exigencies of such cases as this, both in respect of exempting public officers from liability for costs, and providing for the substitution of their successors, as parties, in case of death, resignation, or removal.
The courts have no discretion in the premises. In the absence of legislation making another rule, they must treat the action as personal, the writ as directed to the person temporarily occupying the office and not to the office itself. It is for this reason that the Supreme Court has invariably refused to permit the defendant’s successor in office to become a party to the cause in his stead. United States, ex rel. Bernardin, v. Butterworth, 169 U. S. 600. In that case the subject is carefully reconsidered and the doctrine reaffirmed by the majority of the court after a review of former decisions.
Mr. Justice Shiras, who delivered the. opinion of the majority, adopted a part of the opinion in United States v. Boutwell, 17 Wall. 604, from which we quote the following extracts as governing the question of costs here presented: “It is the personal default of the defendant that warrants impetration of the writ, and if a peremptory mandamus be awarded the costs must fall upon the defendant. ... If a successor in office may be substituted, he may be mulcted in costs for the default of his predecessor, without any delinquency of his own.” Affirmed.