delivered the opinion of the court.

This is an appeal from a decree on a; bill in-equity filed ih the Circuit Court of the United States for the District of Vermont against the Commissioner of Patents, under § .4915-Rev. Stat. That section is as follows: .

“ Seo. 4915. Whenever a patent oh application is refused,, either by the Commissioner -of Patents or by the- {Supreme;1 Court of the. District of Columbia upon appeal from the Com5-' missioner, the applicant may have remedy by bill in equity; and the court having cognizance .thereof, orí notiee to adverse parties and other due proceedings had, may adjudge that sueb - *130 applicant is entitled, according to law, to receive a patent for bis invention as specified in bis claim, or for any part thereof, as tbe facts in tbe case may appear. And sncb adjudication, if it be in favor of the right of tbe applicant, shall authorize tbe Commissioner to issue such patent on the applicant filing in the Patent Office a copy of the adjudication, and otherwise complying with the requirements of law. In all cases where there is no opposing party, a copy of the bill shall be served on the Commissioner; and all the expenses of ’the proceeding shall be paid by the applicant, whether the final decision is in his favor or not.” . .

'On the fifing of the bill, a subpoena was issued commanding the “ Commissioner of -Patents pf the United States of Arnera ica” to appear before the court in Vermont and answer. On the 18th of October, 1883, the Commissioner made the following indorsement on the writ:

“WASHINGTON, D. C., October 18th, 1883.

I hereby accept service of the within subpoena, to have the samé effect as if duly served on me by a proper officer, and I do hereby acknowledge the receipt óf a copy thereof. '

“ E. M.' Marble,

“ Oom'r. of Patents.

(Office of Commissioner of Patents. Received Oct. 18,1883.)”

And afterwards,-and on said 23d day of October, a. d. • 11883, a letter from the Commissioner of Patents was filed, which said letter is in the words and figures following: -

“DEPARTMENT OF THE INTERIOR, . •

United. States Patent Office,

Washington, D. 0., October 18,1883.

. “Sir : I am in receipt of your letter of the 16th instant, enclosing copy of a bill of complaint entitled Hill & Prentice et al.'i). Th.e Commissioner of Patents of the United States of America, in the United States Circuit Court for the District of Vermont, praying that said court direct th'e Commissioner 'of Phtents to issue a patent to the assignees of .Hill & Prentice *131 for tbe invention disclosed and claimed in their application filed in this'office March 30, 1880, for an iifiprovement in milk coolers; also; a subpoena to appear and answer to said bill on the 5th proximo and a certified copy of said subpoena. I herewith return the subpoena, service accepted, and have to inform you'that I shall not' appear in defence in said bill.

“Yery Respectfully,

■ “ E. M. Marble, Commissioner.

!l Me. W. E. SiMONps, Hartford, CbnnP

■ No other service of process was made on the' Commissioner, and he made no other appearance in the cause than such-as may be'implied from his acceptance of service and his letter as above. • In due course of proceeding a decree was entered adjudging that “ Samuel Hill and Benjamin B. Prentice, as inventors, and the-Yermoni Machine Company, as assignee of skid inventors, are entitled to have issued to them letters patent . .■ .■ as prayed for in'the petition and bill of complaint.” No one was made defendant to the bill except the Commissioner of Patents; and. Hill, Prentice and the Machine Com-' pany, the complainants, were all citizens of Yermont. Benjamin Butter worth,-the Commissioner of Patents, took this appeal, and the only question presented under it for our consideration is whether the Circuit Court of the District of Yer-mont had jurisdiction so. as to bind the Commissioner by the decree which- was rendered.

It is contended that the Supreme Court' of the District of Columbia has exclusive jurisdiction of suits- against' the Commissioner brought under this' section of'the Revised- Statutes./ In the view we take of this case, however, that question need not be decided. By § 739 Rev. Stat., as well as by the act of •' March 3, 1875, -ch. 137, § 1, 18 Stat. 470,' it is provided in sub- > stance that, with some exceptions which do not apply to this case, “ no civil suit shall .be brought before either-of said courts N--[the Circuit or District Courts of the .United- States] against an inhabitant of the United States, by any original process, in any other district than that of which he is an inhabitant, or in which ■he may be found at the time of serving the writ.” We enter *132 tain no doubt that this statute applies to suits brought 'under § 4915. The ápplicant is .to have his remedy under that section • by bill in equity, and by the adjudication “ of the court having • cognizance thereof, on fiotice to adverse parties and other due proceedings had.” ,A bill in equity implies a suit in equity, with process and parties. The prayer for process is ..one of. the component part's of the structure of a bill, and its purpose is to compel the defendant to appear and abide .the détermination- of the court on the subject-matter of the proceeding. St'ory, Eq. Ply § 44.

The. bill in this .case was filed against the Commissioner alone, and it does not appear that he was an inhabitant of .the district of Vermont. The Patent,Office is in the Department of.the Interior, Rev.-Stat., § 475, which is one of the Executive’ Departments of the Government at the seat of government in the. District of Columbia. Rev. Stat., § 437. The C.ommis-, sioner of Patents is by law located in the Patent Office.: Rev. -Stat, | 476. . His. official residence'is, therefore, at 'Washing-tori, in the District of Columbia.

The subpoena in this case was delivered to him in the District. of Columbia, and his acceptance of service was made there. That, is apparent from the face of his indorsement and the let- ' ter which was written afterwards,' and filed in the 'cause, .undoubtedly as proof of a delivery of a copy of the bill which the law required should be served on' him. •• Both the indorsement’ and the letter purport to .have been written at Washington, and- the letter in the .Patent .Office.. Unless, therefore, the acceptance of service^ as indorsed on' the writ is to be treated .as-a; voluntary appearance by the Commissioner in the court in 'Vermont, without objection to the jurisdiction, the case stands asit would if the process had been actually served on him in the District of Columbia by some competent officer. The’Circuit Court was1 of opinion .that, by his acceptance of service the Commissioner waived all objection .to the jurisdiction and consented'to be sued away from the seat, of, government and from Chis- résidence. In this we think there was error. ■ The fair; meaning of the indorsement on the writ is that the Commissioner admits the.service with the same effect--it would have if' *133 made by an officer in the District of' Columbia. No appearance is ihereby entered in the cause. Service of the subpoena' in the District is acknowledged, but nothing more. In. the letter which followed the indorsement of' service, both counsel and the court were informed that the Commissioner declined to appear. The parties proceeded, therefore, at their own risk' and without the consent of the defendant to the jurisdiction of the court. Such being the case; we are of opinion that the ■ court was without jurisdiction and had no authority to enter the decree which has been appealed from. ' The act of Congress exempts a defendant from suit in any district' of which he is not an inhabitant, or in which he is not found at the time of the service of the;writ. It is an exemption which he' may waives, but unless waived he need not answer and will not be bound by anything which may be done against, him in his absence. . What is here said of course does not apply to cases where the suit is brought and service is made under §§.,736, 737,* and 738 of the Revised. Statutes.

Without considering any of. the other questions which have been presented in the argument, or which might be suggested under the statute,

We reverse the .decree of the Circuit Court and rema/nd the cause, with instructions to dismiss the hill without greju-, dicefor wa/nt of jurisdiction.