into a state court and claims that, by reason of his own untruthful admission of citizenship, the Federal court assumed a jurisdiction which in fact it could not take, and that all the proceedings in that court must go for naught. Under such circumstances there can be no doubt that the Federal court may inquire and determine whether its proceedings were a nullity, and such inquiry is not an original proceeding, but ancillary to those which have already been had. In other words, a Federal court, exercising a jurisdiction apparently belonging to it, may thereafter, by ancillary suit, inquire whether that jurisdiction in fact existed. It may protect the title which it has decreed as against every one a party to the original suit and prevent that party from relitigating the questions of right which have already been determined. French, Trustee, v. Hay, 22 Wall. 250; Cole v. Cunningham, 133 U. S. 107; Root v. Woolworth, 150 U. S. 401. In this case, on page 410, it was said:

"It is well settled that a court of equity has jurisdiction to carry into effect its own orders, decrees, and judgments, which remain unreversed, when the subject-matter and the parties are the same in both proceedings. The general rule upon the subject is thus stated in Story's Equity Pleading, 9th ed., § 338: 'A supplemental bill may also be filed, as well after as before a decree; and the bill, if after a decree, may be either in aid of the decree, that it may be carried fully into execution.'

"The jurisdiction of courts of equity to interfere and effectuate their own decrees by injunctions or writs of assistance in order to avoid the relitigation of questions once settled between the same parties, is well settled. Story's Eq. Jur. § 959; Kershaw v. Thompson, 4 Johns. Ch. 609, 612; Schenck v. Conover, 13 N. J. Eq. [2 Beasley] 220; Buffum's Case, 13 N. H. 14; Sheperd v. Towgood, Tur. & Rus. 379; Davis v. Black, 6 Beav. 393. In Kershaw v. Thompson, the authorities are fully reviewed by Chancellor Kent, and need not be reëxamined here."

See also Julian v. Central Trust Company, 193 U. S. 93,

which is very much in point. There, after a suit in a Federal court for foreclosure of a mortgage resulting in decree, sale, confirmation and delivery of possession to the purchaser, a state court attempted to subject the property to a judgment rendered in that court against the mortgagor on a cause of action arising subsequently to the delivery of possession under the foreclosure proceedings. And it was held within the competency of the Federal court to restrain the action in the state court in order to protect the title it had conveyed by the foreclosure proceedings. In the opinion it was said (p. 112):

"If the sheriff is allowed to sell the very property conveyed by the Federal decree, such action has the effect to annul and set it aside, because in the view of the state court it was ineffectual to pass the title to the purchaser. In such case we are of opinion that a supplemental bill may be filed in the original suit with a view to protecting the prior jurisdiction of the Federal court and to render effectual its decree. Central Trust Co. of New York v. St. Louis, Arkansas &c. Railroad Co., 59 Fed. Rep. 385; Fidelity Ins. Trust & Safe Deposit Co. v. Norfolk & W. R. R. Co., 88 Fed. Rep. 815; State Trust Co. v. Kansas City &c. R. R. Co., 110 Fed. Rep. 10.

"In such cases where the Federal court acts in aid of its own jurisdiction and to render its decree effectual, it may, notwithstanding sec. 720, Rev. Stat., restrain all proceedings in a state court which would have the effect of defeating or impairing its jurisdiction. Sharon v. Terry, 36 Fed. Rep. 337, per Mr. Justice Field; French v. Hay, 22 Wall. 250; Deitzsch v Huidekoper, 103 U. S. 494."

It must be borne in mind in this connection that the Huguley Manufacturing Company was made a party defendant and appeared in the original foreclosure suit, and also that it had purchased the property and owned it subject to the trust deed. So the bill in the state court specifically avers, and the record of the proceedings in the foreclosure suit shows that it took an active part in the litigation. It admitted in that litigation that it was a citizen of Georgia. It now goes into a state court

and, averring that it is a citizen of Alabama, the State of which the plaintiff was a citizen, contends that the United States court in Georgia had no jurisdiction; but having been in that United States court litigating the case on its merits and its rights there determined, that court has power to protect its decree as against any action which such litigant may take in any other court.

It must also be remembered that the trust deed described the property conveyed as situated partly in Georgia and partly in Alabama. The Federal court sitting in Georgia had jurisdiction to foreclose that trust deed. Muller v. Dows, 94 U. S. 444. Even if there were errors or irregularities in the proceedings they would not affect the matter of jurisdiction, and as those proceedings have been sustained on appeal we may assume that they were free from errors.

Where parties litigate in a Federal court, whose jurisdiction is invoked on the ground of diverse citizenship, and that diverse citizenship is alleged and admitted, the judgment or decree which is entered is conclusive and cannot be upset by either of them in any other tribunal on the mere ground that there was in fact no diverse citizenship. Skillern's Executors v. May's Executors, 6 Cranch, 267; McCormick v. Sullivant, 10 Wheat. 192; Hancock v. Holbrook, 119 U. S. 586. In Des Moines Navigation Company v. Iowa Homestead Company, 123 U. S. 552, 557, we said:

"It was settled by this court, at a very early day, that, although the judgments and decrees of the Circuit Courts might be erroneous, if the records failed to show the facts on which the jurisdiction of the court rested, such as that the plaintiffs were citizens of different States from the defendants, yet that they were not nullities, and would bind the parties until reversed or otherwise set aside."

In Dowell v. Applegate, 152 U. S. 327, the validity of a decree rendered by a Federal court was challenged on the ground of a want of jurisdiction. In the opinion the question was thus stated (p. 337):

"If the Federal court erred in assuming or retaining jurisdiction of Dowell's suit-a question not necessary to be examined-would it follow that its final decree, being unmodified and unreversed, can be treated as a nullity when assailed collaterally by one who was a party to the suit in which it was rendered?"

And after quotations from several authorities the conclusion was reached (p. 340):

"This disposes of the first objection urged against the decree in the Federal court under which Dowell purchased. That decree cannot be treated, in this suit, as void for want of jurisdiction."

See also Evers v. Watson, 156 U. S. 527.

Some of these cases, as appears from the quotations, go to the extent of holding that, although on the face of the record, jurisdiction does not appear, yet the judgments or decrees are binding upon the parties thereto and cannot be assailed collaterally. A fortiori, must it be true that when on the face of the record jurisdiction appears the judgment or decree must be held conclusive against a collateral attack by either of the parties thereto. The Huguley Manufacturing Company was, as is conceded in these ancillary proceedings, a party to the original litigation, and cannot now be permitted to challenge the jurisdiction of the Federal court on the ground that its admission of citizenship was an error, and that a correct statement would have disclosed a lack of jurisdiction.

As appears from the record, the Huguley Manufacturing Company was the owner of the equity of redemption at the time the foreclosure suit was instituted. It, therefore, was unnecessary to make the original grantor in the trust deed a party to the litigation. All that could be accomplished by its presence would be a decree putting at an end all question of its interest, and, possibly, if a sale did not pay the debt, a judgment over for the deficiency. But neither of these results would affect the jurisdiction of the court, so far as the owner of the equity of redemption is concerned, or impede

the transfer of the title by foreclosure and sale to the purchaser.

Under the averments of the ancillary bill and answer it must be accepted that there were two corporations under the same name, the Alabama and Georgia Manufacturing Company, one chartered in Alabama, and the other in Georgia. It is doubtless true that, for the purposes of jurisdiction in the Federal courts, these corporations are deemed to be citizens of the States in which they were organized. It is also true that there was no formal merger of the two corporations into one; that they remained in law two separate legal persons, and that each was entitled to corresponding rights. But courts will sometimes look beyond the formal and corporate differences. Especially is this true of courts of equity. Substantial rights will be regarded rather than the mere matter of organization. Lehigh Mining & Manufacturing Company v. Kelly, 160 U. S. 327, illustrates this. There it appeared that the Virginia Coal and Iron Company was a corporation organized under the laws of Virginia, and therefore a citizen of that State; that it claimed title to certain lands in Virginia in the possession of the defendant, also a citizen of Virginia. There being no diversity of citizenship, an action could be maintained only in a court of the State. To avoid this and to place the litigation in the Federal court the stockholders of the coal and iron company organized under the laws of Pennsylvania the Lehigh Mining and Manufacturing Company. The former company thereupon conveyed all its rights to the latter, which brought its action for the recovery of the property in the United States Circuit Court for the District of Virginia. While it was conceded that the purpose with which a party makes a conveyance does not affect the title of his grantee, and while it was not doubted that the two corporations were separate entities, yet it was also held that, inasmuch as the stockholders in each were the same, and the organization of the Pennsylvania company was only for the purpose of getting the litigation into the Federal court, it was a fraud on the jurisdiction of that