for the infringement of a patent in one district is no bar to a suit against the same defendant for the infringement of the same patent in another district; but, in the latter suit, the court will only consider and adjudicate upon alleged infringements within its district if the defendant resides or has made a general appearance in the former.57 Ownership or part-ownership by defendant of the patent which is the foundation of the bill,58 a license,59 and estoppel,60 are affirmative defenses which must be pleaded. But where the defendant has pleaded a patent of prior date to that alleged in the bill and the complainant undertakes to carry the date of his invention further back without having so alleged in his pleading, the defendant may, it has been held, meet such proof by the defense of laches or abandonment without pleading the same.61 It has been held: that the Federal statute of limitations, six years, to the recovery of profits or damages for the infringement of a patent,62 need not be pleaded in the answer, nor need it be negatived in the bill,63 but it is a defense as to which the defendant bears the burden of proof; 64

The complainant has the burden of proving that the patentee was the original and first inventor of the invention patented.65 Ordinarily the patent itself creates a presumption upon this point in his favor.66 Where subsequent to its issue another patent for the same invention was granted to an earlier applicant it was held that the mere priority of date did not establish the presumption.67 An invention to be patentable must be useful and a patented device must be operated.68 It seems that the issue of a patent creates a rebuttable presumption of the utility of the in

57 Warren Bros. Co. v. City of Montgomery, 172 Fed. 414.

58 Puetz v. Bransford, 31 Fed. 458.

59 Watson v. Smith, 7 Fed. 350; Puetz v. Bransford, 31 Fed. 458. 60 Pennsylvania Co. v. Cole, 132 Fed. 668; supra, § 185a.

61 Curtain Supply Co. V. Nat. Lock Washer Co., 174 Fed. 45.

62 29 St. at L. 694; supra, § 180. 63 Peters v. Hanger, C. C. A., 134 Fed. 586.

64 Ibid. The fact that the owner of a patent permitted a suit for

its infringement to be dismissed without a trial on the merits is not such laches as to bar a second suit against the same defendant, Welsbach Light Co. v. Cohn, 181 Fed. 122.

65 West Coast Roof & Mfg. Co. v. Elaborated Ready Roof Co., C. C. A., 249 Fed. 221, 226.

66 Mygatt v. Schaffer, C. C. A., 218 Fed. 827.

67 Ibid.

68 Troy Laundry Mach. Co. v. Columbia Mfg. Co., 217 Fed. 787.

vention.69 It was held that evidence that the owner of the patent had made but had ceased to make the patented article was not admissible as tending to prove its inutility:70 Where there was a dispute as to the usefulness of the invention and it appeared that neither the patentee nor any subsequent owner had used it practically it was held that the owner had failed to produce convincing evidence which was within his possession and that the fullest weight must be given to the defendant's proofs.71

The plaintiff has the burden of proof as to infringement, even when the defendant pleads a license as well as non-infringement.72 Where the answer admitted that defendant, during the time alleged in the bill, had made and used articles conforming to the claims of the patent, no further proof on the issue of infringement was required from complainant,73 Where the defendant in its proposal for a Government contract which had been accepted specified a machine which would have infringed the patent, in the absence of evidence from the defendant showing what machine it furnished under the contract, the Court found an infringement.74 Proof that defendant's device was made under a later patent does not create a presumption of noninfringement.75

The defendant has the burden of proving the defenses of anticipation and prior use beyond a reasonable doubt.76

69 Ibid.

70 Ibid.

71 Troy Laundry Mach. Co. v. Columbia Mfg. Co., 217 Fed. 787.

72 Niagara Fire Extinguisher Co. v. Hibbard, C. C. A., 179 Fed. 844. 73 Fox v. Knickerbocker Engraving Co., C. C. A., 165 Fed. 442. In a suit for infringement against the Hygienic Chemical Company of New York, where it was shown that defendant was a selling company only, while the Hygienic Chemical Company of New Jersey was a manufacturing company only, the testimony of a witness that he purchased an article shown to be an infringement from the "Hygienic Chemical Company" in New York

is sufficient, prima facie, to establish infringement by the defendant. Rumford Chemical Works v. Hygienic Chemical Co., C. C. A., 159 Fed. 436.

74 Int. Curtis Marine Turbine Co. v. William Cramp & Sons Ship & Eng. Bldg. Co., C. C. A., 202 Fed. 932.

75 Simplex Window Co. v. Hauser Reversible Window Co., C. C. A., 248 Fed. 919.

76 Beckwith V. Malleable Iron Range Co., 174 Fed. 1001; Diamond Patent Co. v. S. E. Carr Co., C. C. A., 217 Fed. 400; A. B. Dick Co. v. Underwood Typewriter Co., 246 Fed. 309; Taignian v. Desure, C. C. A., 253 Fed. 364.

A plea to a bill for an injunction to restrain the infringement of a reissued patent, which set up that the claim had been unlawfully expanded'so as to embrace subsequent improvements covered by later patents, was held good.77 A plea to a bill filed ́under section 4918 of the Revised Statutes against the owner of a patent interfering with that of the complainant, which set up that the invention described in the complainant's patent was described in a previous English patent published in the United States, and filed in the Patent Office here before the issue of the complainant's patent, was held bad and overruled.78

§ 189. Proceedings to compel answer. By the Equity Rules of 1912, if the defendant fails to file his answer or other defense to the bill in the clerk's office within the time named in the subpoena, "the plaintiff may, at his election, take an order as of course that the bill be taken pro confesso; and thereupon the cause shall be proceeded in ex parte."1 "Averments other than of value or amount of damage, if not denied, shall be deemed confessed, except as against an infant, lunatic or other person non compos and not under guardianship." 2 They contain no other provision for proceedings to compel an answer. By the rules of 1842 "The plaintiff, if he requires any discovery or answer to enable him to obtain a proper decree, shall be entitled to process of attachment against the defendant to compel an answer, and the defendant shall not, when arrested upon such process, be discharged therefrom, unless upon filing his answer, or otherwise complying with such order as the court or a judge thereof may direct, as to pleading to or fully answering the bill, within a period to be fixed by the court or judge, and undertaking, to speed the cause."3 The ancient practice upon the subject was substantially the same. If the defendant did not file an answer within due time, he was in contempt and an attachment was issued against him.4 If the sheriff was unable to attach the defendant and returned accordingly non est inventus, a commis

77 Hubbell v. De Land, 14 Fed. 471.

78 Pentlarge v. Pentlarge, 19 Fed. 817; s. c., 22 Fed. 412. But see Foster v. Lindsay, 3 Dill. 126, 131. 1 Eq. Rule 16.

$ 189.

2 Eq. Rule 30.

3 Eq. Rule 18 of 1842.

4 Matter of Vanderbilt, 4 J. Ch. (N. Y.) 58. See Daniell's Ch. Pr., (First Am. ed.) 538.

sion of rebellion would issue. If that proved insufficient, it was followed by a writ of sequestration.

§ 190. Frame of answer. An answer should be entitled in the cause, so as to agree with the names of the parties as they appear in the bill at the time the answer is filed. It seems that the defendant may not correct or alter the names of the parties as they appear in the bill, and that if there is a mistake he must correct it in the part following the title of the cause; thus, "The answer of the defendants, the mayor, aldermen, and commonalty in the bill called the mayor, aldermen, and citizens of the city of New York." 2 The answer should begin substantially thus: "The answer of John Aber, one of the above-named defendants, to the bill of complaint of the abovenamed plaintiff;" if the bill has been amended after answer, "to the amended bill of complaint."3 A female defendant who has married since the filing of the bill, usually begins: "The answer of John Aber and Anna, his wife, lately in the bill called 'Anna Brown, spinster," or widow, as the case may be. A title, "the several answer of John Peck, Esq., one of the defendants to the bill of complaint of Anna Baines, alias Green, assuming to herself the name of Anna Peck, as pretended wife of John Peck, Esq., deceased, and of Anna Maria Green, assuming to herself the name of Anna Maria Peck, as daughter of the said John Peck, Esq., deceased," was held scandalous. An answer by a person defending by guardian or next friend should state that fact: "James Fifield by Edward Jennings, his next friend." 6 If two or more defendants join in the same answer, it usually begins, "The joint and several answer; unless they are husband and wife, when it is "The joint answer;" 8

5 Boudinot v. Symmes, Wall. C. C. 139; Smith's Ch. Pr. (2d ed., 1837), 183, 186.

6 Smith's Ch. Pr., (Second ed. 1837) 183-188; Daniell's Ch. Pr., (First Am. ed) 543; Davis v. Hammond, 5 Sim. 9.

§ 190. 1 Daniell's Ch. Pr. (5th Am. ed.) 731.

2 Atty. Gen. v. Worcester Corp. 1 C. P. Cooper, 18; Daniell's Ch. P1. (5th Am. ed.) 731.

3 Daniell's Ch. Pr. (5th Am. ed.) 731; Rigby v. Rigby, 9 Beav. 311, 313.

4 Daniell's Ch. Pr. (5th Am ed.) 731.

5 Peck v. Peck, Moseley, 45. 6 Daniell's Ch. Pr. (5th Am. ed.) 731.

7 Davis v. Davidson, 4 McLean, 136.

8 Daniell's Ch. Pr. (5th Am. ed.) 731.

but an answer is not defective if put in by several as a joint answer merely.9

When discovery is required, all of the defendants who join in an answer must swear to the same.10 When the same solicitor is employed for two or more defendants, and separate answers are filed, or other proceedings had by two or more defendants separately, costs, were under the practice in chancery, not allowed for such separate answers or other proceedings, unless a master, upon reference to him, certified that such separate answers and other proceedings were necessary or proper, and ought not to have been joined together.11

Next followed formerly a clause reserving to the defendant any and all advantages that might be taken by exception to the bill.12 This was always useless 13 and is forbidden by the Equity Rules of 1912.14

Then comes the substantive part of the answer, setting up the matters of affirmative defense and giving the discovery required.16

Next should be inserted any counter-claim or set-off upon which the defendant relies. 16 It is the safer practice to specifically describe the matter thus pleaded as a counter-claim or setoff, as the case may be.17

The answer usually closes with a general traverse inserted out of abundant caution, denying the unlawful combination charged in the bill, and all other matters therein contained.18

In the answers of infants and other persons under a disability, the reservation and general traverse have always been deemed properly omitted.19 The answer in such cases generally is that the infant knows nothing of the matter, and therefore neither admits nor denies the charges, but leaves the plaintiff to prove

17 Bates v. Rosekrans, 37 N. Y. 409; Ward v. Conegys, 2 How. Pr. N. S. (N. Y.) 428; Burke v. Thorne, 44 Barb. (N. Y.) 363; Burral v. De Groot, 5 Duer (N. Y.) 379; Equitable Life Ass'n.'v. Cuyler, 75 N. Y. 511, affirming 12 Hun, 247. But see Acer v. Hotchkiss, 97 N. Y. 395. 18 Mitford's Pl., ch. 2, § 2, part 3, Story's Eq. Pl., § 870.

19 Story's Eq. Pl., § 871.