licensee from proving the state of the prior art for the purpose of limiting the scope of the patent. Nor from denying the infringement.17 A complainant is not estopped to attack a patent, introduced by defendant as part of the prior art, which was originally pleaded in the bill but afterwards abandoned.18 It has been held that the assignor cannot escape the estoppel by alleging that he was induced to part with the patent by unfair, representations.19 But in a later case a defendant was permitted to deny the complainant's title to the patent and in a counterclaim allege equitable ownership in itself and pray for a decree quieting its title.20 An allegation in an answer to a suit for infringement that the Government had begun a suit for the dissolution of the complainant company as an illegal monopoly was held to be irrelevant.21 In a suit for the cancellation of an interfering patent the answer may allege any objection to the validity of the patent of the complainant ;22 it was held that in such a suit allegations as to the decision of questions in a prior suit between different parties were irrelevant.23 The notice required by the rule, need not be under oath, and a consent to an order that the answer be considered as amended by the insertion of such defense and notice is a waiver of any further oath.24 Under this statute it has been held that no evidence can be admitted in support of any of these defenses unless it has been properly pleaded and the requisite notice has been given to the complainant; 25 the complainant's patent is then prima facie Fed. 81; Standard Plunger Elevator Co. v. Stokes, C. C. A., 212 Fed. 941; Mergenthaler Linotype Co. v. Int. Typesetting Mach. Co., 229 Fed. 168, 172; H. D. Smith & Co. v. Southington Mfg. Co., C. C. A., 247 Fed. 342. 17 H. D. Smith & Co., v. Southington Mfg. Co., C. C. A., 247 Fed. 342; Moon-Hopkins Billing Mach. Co. v. Dalton Adding Mach. Co., C. C. A., 236 Fed. 936. 18 Mergenthaler Linotype Co. v. Int. Typesetting Mach. Co., 229 Fed. 168, 173. 19 Vacuum Eng. Co. v. Dunn, C. C. A., 209 Fed. 219. 20 Cleveland Eng. Co. v. Galion D. M. Truck Co., 243 Fed. 405. 21 Motion Pict. Patent Co. V. Eclair Film Co., 208 Fed. 416. 22 Nikola Tesla Co. v. Marconi Wireless Tel. Co., 227 Fed. 903. 23 Nikola Tesla Co. v. Marconi Wireless Tel. Co., 227 Fed. 903. See infra, § 237. 24 Campbell v. Mayor of N. Y., 45 Fed. 243. 25 Teese v. Huntington, 23 How. 2, 16 L. ed. 479; Agawam Co. v. Jordan, 7 Wall. 583, 19 L. ed. 177; Blanchard v. Putnam, 8 Wall. 420, 19 L. ed. 433; Bates v. Coe, 98 U. S. 31, 25 L. ed. 68; Pitts v. Ed evidence of the priority of his invention; 26 but the respondent, after pleading these defenses or some of them, with the names of such of the persons therein referred to as he knows, may also plead a general allegation "that the same had been previously invented and known and used by many other persons whose names are unknown to the respondent, which, when known, the respondent prays leave to insert and set forth in the answer." 27 Upon the subsequent discovery of any such persons, testimony concerning them may be taken, and leave obtained from the court to insert their names in the answer by amendment nunc pro tunc. An order to this effect may be obtained before or after the testimony has been taken.2 28 The omission to serve the notice will be waived if the defendant fails to move to strike out the defense as insufficient or to object to the evidence as to the matters which should have been therein included.29 An averment that a patent "was obtained upon false and fraudulent representations by the plaintiffs, or some of them, made to the Commissioner of Patents, and is wholly void at law," is too uncertain to be sufficient to constitute a defense.80 In pleading prior patents, it is sufficient to give their number and date and the name of the patentee.31 In pleading prior publications, they must be clearly identified or a copy thereof must be filed.32 Where a prior device which is pleaded as anticipation may be made the subject of an exhibit, the defendant will not be required to set forth the drawings thereof but the complainant may be allowed an inspection before testimony is taken.33 In pleading prior use, the time and place thereof must be set forth with such directness and certainty as will enable complainant to go upon the ground and determine what acts there done monds, 2 Fisher, 52, 26 Fay v. Mason, 120 Fed. 506. 220, 24 L. ed. 384, 386; Brown v. Hall, 6 Blatchf. 405. 28 Ibid. 29 Monroe v. Bresee, C. C. A., 239 Fed. 727. 30 Clark v. Scott, 5 Fisher, 245. 31 Corrugated Metal Co. v. Pattison, 197 Fed. 577. 32 Ibid. 33 Todd v. Whitaker, 217 Fed. 319. may be relied on.34 The omission of the place of the use makes the notice fatally defective.35 But a notice is not defective for failure to state the particular place within a specified city at which the defendant proposes to prove the previous use.36 Evidence stated in a notice to be proposed for one purpose cannot be used for another.37 The defenses that complainant was not the original inventor and that the thing patented had been in public use or on sale for more than two years before his application, or had been abandoned, are distinct from each other, and if the defendant relies upon both he must give notice accordingly.38 It seems that when a previous patent has not been referred to in an answer, such patent may still be proved, as evidence of a prior use of the invention, which has been properly pleaded,39 to show the state of the art at the date of the complainant's alleged invention,40 and to aid in the proper construction of the patent in suit.41 The state of the art can always be pleaded without notice. When two applications are pending in the patent office at the same time neither is prior art as against the other since neither applicant had a right to know of the other's application.43 Where the answer alleges want of invention and novelty in view of the prior art an article shown to have been manufactured and on sale before the patent may be admitted in evidence although not specifically pleaded." A patent subsequent to that upon which the complainant relies may be offered in evidence upon the issue of infringement 34 Ibid. 35 Schenck v. Diamond Match Co., C. C. A., 77 Fed. 208; s. C., 71 Fed. 521. 36 Wise v. Allis, 9 Wall. 737, 19 L. ed. 784. 37 Pennock v. Dialogue, 4 Wash. 538; s. c., 2 Pet. 1, 7 L. ed. 327. 38 Meyers v. Bushby, 32 Fed. 670. 39 Atlantic Works v. Brady, 107 U. S. 192, 27 L. ed. 438. But see Parks v. Booth, 102 U. S. 96, 105, 26 L. ed. 54, 57; Kennedy v. Solar Ref. Co., 69 Fed. 715. 40 Am. S. Co. v. Hogg, 1 Holmes, 133; s. c., 6 Fisher, 67; Stevenson v. Magowan, 31 Fed. 824; Morton v. Llewellyn, C. C. A., 164 Fed. 693; Campbell v. Skinner, 236 Fed. 359; Simplex Window Co. v. Hauser Reversible Window Co., C. C. A., 248 Fed. 919; H. D. Smith & Co. v. Southington Mfg. Co., 235 Fed. 160. 41 Morton v. Llewellyn, C. C. A., 164 Fed. 693. 42 Vance v. Campbell, 1 Black, 427, 17 L. ed. 168; Brown v. Piper, 91 U. S. 37, 23 L. ed. 200. 43 Mergenthaler Linotype Co. v. Int. T. Mach. Co., 229 Fed. 168, 172. 44 Johnson v. Lambert, C. C. A., 234 Fed. 886. when one of the articles alleged to be infringements was made thereunder.45 It has been held that a witness may be asked whether the defendant's machine is similar to a model of the plaintiff's patented machine, although no notice of such testimony has been given.46 The defenses that the plaintiff's device is not patentable and that it is not workable 47 need not be pleaded in the answer.48 It is unsettled whether the defense of insufficient description can be set up without alleging an intent to deceive the public. 49 The statute requires notice of the names and residences of the inventors and of those who have the prior knowledge of the thing 45 Reis v. Rosenfeld, C. C. A., 204 Fed. 282. 46 Evans v. Hettick, 7 Wheat. 453, 469, 5 L. ed. 496, 500. 47 May v. Juneau County, 137 U. S. 408, 34 L. ed. 729; Stevenson v. Magowan, 31 Fed. 824; Wills v. Scranton Cold Storage & Warehouse Co., C. C. A., 155 Fed. 181. It has been said concerning the defense of want of novelty: "Where the thing patented is an entirety, consisting of a separate device or of a single combination of old elements incapable of division or separate use, the respondent cannot make good the defense in question by proving that a part of the entire invention is found in one prior patent, printed publication, or machine, and another part in another, and so on indefinitely, and from the whole or any given number expect the court to determine the issue of novelty adversely to the complainant." "Defense of the kind, if the thing patented is an entirety, incapable of division or separate use, must be addressed to the invention, and not to a part of it, or to one or more claims of the patent, of less than the entire invention. More than one patent may be included in one suit, and more than one invention may be secured in the same patent; in which cases the several defenses may be made to each patent in the suit, and to each invention, to which the charge of infringement relates." Mr. Justice Clifford, in Parks v. Booth, 102 U. S. 96, 104, 26 L. ed. 54, 57; citing Bates v. Coe, 98 U. S. 31, 25, L. ed. 68. It has been said that a defense charging that the original patentee "fraudulently and surreptitiously obtained the patent for that which he well knew was invented by another, unaccompanied by the further allegation that the alleged first inventor was at the time using reasonable diligence in adapting and perfecting the invention, is not suf ficient to defeat the patent, and constitutes no defense to the charge of infringement." Clifford, J., in Agawam Co. v. Jordan, 7 Wall. 583, 597, 19 L. ed. 177, 180. 68. 48 Hildreth v. Mastoras, 253 Fed. 49 Loom Co. v. Higgins, 105 U. S. 580, 588, 589, 26 L. ed. 1177, 1180, 1181; Grant v. Raymond, 6 Pet. 218, 8 L. ed. 376; Whittemore v. Cutter, 1 Gall. 429; Lowell v. Lewis, 1 Mason, 182; Gray v. James, Pet, C. C. 394. 50 patented, not the names of the witnesses.5 Notice of the time when the person named possessed a knowledge or use of the invention is not required."1 The notice is not a pleading and should be served upon the plaintiff.52 It is the better practice to file the notice with the pleadings after it has been served.53 The pendency of a previous suit for the infringement of certain claims of a patent, specified by number in the bill, is not a bar to a second suit in the same court, between the same parties, for an infringement of different claims of the same patent, also specified in the latter bill, where the two sets of claims cover distinct and separate devices in the same machine.54 When, after a bill has been filed to restrain the infringement of a patent and to obtain an account of profits, the defendant continues his infringements, the pendency of the first is no objection to a second bill seeking an injunction and an account, founded upon the subsequent infringements.55 Notwithstanding a decree for an injunction in the former suit, a decree for an injunetion and account was granted in that for the subsequent infringements, the second injunction being useless except to support the equitable jurisdiction.56 The pendency of a suit 50 Woodbury P. Mach. Co. V. Keith, 101 U. S. 479, 25 L. ed. 939; Roemer v. Simon, 95 U. S. 214, 24 L. ed. 384. 51 Phillips v. Page, 24 How. 164, 16 L. ed. 639. 52 Cottier v. Stimson, 20 Fed. 906. See, also, 10 Saw. 212; Henry v. U. S., 22 Ct. Cl. 75. The defendant may also plead his defense specially if he so desires. Cottier v. Stimson, 20 Fed. 906, 907; Evans v. Eaton, 3 Wheat. 454; Grant v. Raymond, 6 Pet. 218; Phillips v. Combstock, 4 McLean, 525; Day v. N. E. C. S. Co., 3 Blatchf. 179. In such a case it seems that no notice may be given. Cottier v. Stimson, 20 Fed. 906, 907; Evans v. Eaton, 3 Wheat. 454; Grant v. Raymond, 6 Pet. 218; Phillips v. Combstock, 4 McLean, 525; Day v. N. E. C. S. Co., 3 Blatchf. 179. A plea stricken out by the court is not a sufficient legal notice. Silsy v. Foote, 1 Blatchf 445; s. C., 14 How. 18. No demurrer lies to a notice. Henry v. U. S., 22 Ct. Cl. 75. A defect in the notice may be remedied by a second notice without leave of the court. Teese v. Huntingdon, 23 How. 2, 10. 53 Teese v. Huntington, 23 How. 2, 10, 16 L. ed. 479, 482. |