sue of the patent must be construed as applying to the actual invention patented, however this may differ from the one described and claimed in the original application.5 § 819. Reciprocal Rights and Duties of Licensors and Licensees. The reciprocal rights and duties of licensors and licensees are determined by the express provisions of the license, and by implication of law from the relation which exists between them. If the licensee fulfils the conditions of the license, he is entitled to enjoy the privileges therein conferred upon him without interference from the licensor, and to be protected by the licensor against the violation of his rights by others.1 Corresponding to this right of the licensee is the duty of the covered by one Claim of a patent gives no right to use the inventions covered by its other Claims, see United Nickel Co. v. California Electrical Works (1885), 25 Fed. Rep. 475. That the practical construction given to a license by the act of the parties is of great weight, see Rubber Co. v. Goodyear (1869), 9 Wall. 788. 5 That a license given pending an application for a patent covers the patent as granted, however it may differ from the original application, see Kelly v. Porter (1883), 17 Fed. Rep. 519; 8 Sawyer, 482. : § 819. In Cohn v. National Rubber Co. (1878), 3 Bann. & A. 568, Clifford, J. (568) "Inventors whose inventions are secured by valid letterspatent have the exclusive right, for the period allowed by law, to make, use, and vend the thing patented; and by virtue of that right they may assign the patent, or license others to practise the invention. Persons duly licensed by the owner of the patent may make, use, and vend the patented product, within the terms and conditions of their license, without hindrance or interruption by the patentee, if they themselves comply with those terms and conditions." 15 O. G. 829 (829). That a licensee, acting within his li cense, is not an infringer, see Kelly v. Porter (1883), 8 Sawyer, 482; 17 Fed. Rep. 519. That a licensee cannot extend his license by acting beyond its terms, even where the conduct of his licensor is hostile, see Aspinwall Mfg. Co. v. Gill (1887), 40 O. G. 1133; 32 Fed. Rep. 697. That a licensee, authorized to sell materials to be used in a patented process to the licensees of such process, becomes an infringer if he sells the materials for use to others known by him not to be licensees, see Willis v. McCullen (1886), 38 O. G. 1017; 29 Fed. Rep. 641. That a license does not free the licensee from liability when he infringes a different patent not owned by the licensor, see Stuart v. Shantz (1872), 6 Fisher, 35; 2 O. G. 524. That a licensee may deny that his acts are infringements even though his contract forbids him to deny it, see White v. Lee (1882), 23 O. G. 1621; 14 Fed. Rep. 789. That a licensee is bound by his li cense though he neglects to read it before signing or accepting it, see McKay v. Jackman (1883), 17 Fed. Rep. 641. licensor not to permit others to use gratuitously the privilege for whose enjoyment the licensee is compelled to pay, and to prosecute infringers whenever their wrongful acts become injurious to the licensee. If the license is granted upon con 2 In Goodyear v. Honsinger (1867), 2 Bissell, 1, Drummond, J.: (8) "It was unfair, and is always unfair, to those who are licensed to use the particular article or method, under letterspatent, to allow others to use what the licensees have thus purchased. It is true that this conduct may be explained. There may be circumstances such as would not warrant any inference against the patentee, from such conduct; as, for instance, if the patentee were unable to prosecute the parties thus infringing the patents; or, if circumstances were such as to indicate that there was no acquiescence, expressed or implied, in the violation; or, as appears in this case, that there was a suit pending in one of the circuit courts of the United States, where the right under the patent was to be tested. That would constitute a reason why the patentee, or those claiming under him, should not involve themselves in great expense while there might be a question as to the validity of the patent." 3 Fisher, 147 (153). That an exclusive license implies no warranty against infringers, see Baker v. Mason (1854), 3 R. I. 45. That a licensor fulfils his agreement to prosecute infringers if he stops the infringement in any way, see Foster v. Goldschmidt (1884), 22 Blatch. 287; 21 Fed. Rep. 70; 28 O. G. 915. That a licensor covenanting to sue infringers, not to license others, and to use diligence in securing the licensee's rights, is not bound to protect the licensee against those who claim under adverse patents, nor does he warrant against them, nor is he estopped to deny the validity of the patent in an action against him for not suing, or for licensing others, see Jackson v. Allen (1876), 120 Mass. 64. That a patentee, after granting an exclusive license for the term of the patent and agreeing to assign the extended term, cannot contract with third parties against the interests of his licensee, see Adams v. Bridgewater Iron Co. (1886), 26 Fed. Rep. 324; 34 O. G. 1045. That a new license, granted to others in violation of the rights of an existing licensee, makes the licensor liable for all damage resulting, see Pitts v. Jameson (1853), 15 Barb. 310. That an agreement by the licensor not to license any other person is broken by every concession, by suit or otherwise, which operates as a recognition of the rights of others to make and use, whether they are later patentees or not, see Jackson v. Allen (1876), 120 Mass. 64. That where a licensor agrees that royalties shall be reduced if subsequent licenses are granted to others upon lower terms, the licensee cannot insist on the reduction unless he accepts the other burdens imposed upon the later licensees, see Foster v. Goldschmidt (1884), 22 Blatch. 287; 21 Fed. Rep. 70; 28 O. G. 915. That a licensor will not be enjoined from suing for his license fees on the ground that he charges the plaintiffs more than he agreed to, their relief being at law, but he may be enjoined from declaring the license void and thus causing damage to the plaintiffs, see Baker Mfg. Co. v. Washburn & Moen Mfg. Co. (1883), 18 Fed. Rep. 172; 5 McCrary, 504. That suing out and serving an injunction is a breach of the licensor's contract, dition precedent, the condition must be performed before the privileges described can vest in the licensee, and any premature exercise of them will be an infringement of the patent, and render the licensee liable to an injunction.3 Pending the license, a violation of its concurrent conditions by the licensee suspends his privileges, and subjects him to an action for a breach of contract. If he persists in using them after he has, either by words or conduct, repudiated his license, he may be sued as an infringer, and cannot plead his license as a defence.5 When the license is not made irrevocable by its terms, or paid for by a gross sum in advance, the licensor may recall it on condition broken; but an unconditional license, limited 6 see Sullings v. Goodyear Dental Vul- (571) "Licensees, if they fulfil the canite Co. (1877), 36 Mich. 313. That a license may be annulled on account of fraudulent representations of the licensor as to the salability of the invention, see Hull v. Fields (1882), 76 Va. 594. 8 In Goodyear v. Congress Rubber Co. (1856), 3 Blatch. 449, Ingersoll, J. (455) "When a license is granted to any one to use a patent in the manufacture of goods, which license is accompanied with an obligation, in favor of the patentee, on the part of the one to whom it is granted, to do or not to do a particular thing, and which obliga. tion is the consideration upon which the license is granted, he upon whom the obligation rests must perform it, and, if he will not perform it, an injunction will be granted to restrain him from any further right to use the patent under the license." That a licensee, violating the provisions of his license, may be sued on the contract or for infringement, and if the suit is on the contract the damages are the damages from the infringement, see Magic Ruffle Co. v. Elm City Co. (1875), 8 O. G. 773; 13 Blatch. 151; 2 Bann. & A. 152. 5 In Cohn v. National Rubber Co. (1878), 3 Bann. & A. 568, Clifford, J.: stipulations of their licenses, are entitled to practise the invention within the terms and conditions of the instrument, to the extent of the authority conferred without question or impediment by the owner of the patent. Doubt upon that subject cannot be entertained; but if they refuse to perform on their part, and repudiate the license, they may be treated by the owner of the patent, at his election, as infringers. He may have his remedy by suit upon the license, in case they have repudiated the license, or he may elect to treat them in future as infringers of his exclusive rights under the patent. Being infringers, they cannot set up the license in defence of a suit, any more than if they had never possessed any such authority." 15 O. G. 829 (830). See also Moody v. Taber (1874), Holmes, 325; 5 O. G. 273; 1 Bann. & A. 41; Brooks v. Stolley (1845), 3 McLean, 523; 2 Robb, 281. That a purchaser from a repudiating licensee, with notice, will be an infringer, see Moody v. Taber (1874), 1 Bann. & A. 41; 5 O. G. 273; Holmes, 325. ` 6 That where a license is conditional a breach of the condition will avoid the license at the option of the licensor, see A in duration by the life of the patent, is irrevocable. The surrender of a license by one of several joint-licensees does not affect the privileges of the others.8 § 820. Licensee under Express License: When Estopped to Deny Validity of the Patent. A licensee, having accepted a license, and while exercising under its protection the rights therein conferred, is estopped from denying the validity of the patent in any suit in which such exercise of his license privileges is the basis of the controversy. In the absence of express provisions in the license That where a license is avoided for breach of condition both parties are remitted to their original rights, and the licensee may defend against the patent, as if there were no license, see Woodworth v. Cook (1850), 2 Blatch. 151. That a license, unlimited as to time and not conditioned otherwise than on the grant of the patent, is irrevocable, see Kelly v. Porter (1883), 8 Sawyer, 482; 17 Fed. Rep. 519. 8 That the surrender of a license by a part of the licensees does not avoid it as to the others, see Theberath v. Celluloid Mfg. Co. (1880), 3 Fed. Rep. 143; 5 Bann. & A. 577. § 820. That an assignor taking a license under his assignee is estopped to deny the validity of the patent, see Consolidated Middlings Purifier Co. v. Guilder (1881), 3 McCrary, 186; 9 Fed. Rep. 155. That a licensee who has enjoyed without disturbance the benefit of a patent cannot dispute its validity in a suit for compensation, see Deane v. Hodge (1886), 35 Minn. 146. That an exclusive licensee, not evicted, and benefiting by the license, cannot impeach the patent on a suit for royalties, see Rogers v. Reissner (1887), 41 O. G. 351; 30 Fed. Rep. 525; McKay v. Jackman (1883), 17 Fed. Rep. 641; White v. Lee (1882), 14 Fed. Rep. 789; 23 O. G. 1621. That a defendant in a suit brought to recover license fees, payable according to the quantity made, cannot deny the validity of the patent unless fraud has been practised upon him, for having had the benefit he must pay for it, see Wilder v. Adams (1846), 2 W. & M. 329. That a purchaser from the licensee is not estopped to deny the validity of the patent, in a suit for infringement, see Baltimore Car Wheel Co. v. North Baltimore Passenger R. R. Co. (1884), 21 Fed. Rep. 47. That a licensee is not necessarily estopped by his license, nor prevented from making any defence that any other defendant could, see Burr v. Duryee (1862), 2 Fisher, 275. That a licensee, while claiming under the license, is estopped to deny the validity of the patent, see Brown v. Lapham (1886), 23 Blatch. 475; 27 Fed. Rep. 77; 37 O. G. 676; Baltimore Car Wheel Co. v. North Baltimore Passenger Ry. Co. (1884), 21 Fed. Rep. 47. That a licensee cannot deny the consideration of his license after long delay and the enjoyment of all its benefits, see Davis v. Gray (1867), 17 Ohio St. 330. That a licensee sued for license fees may deny the originality of the inven to the contrary, however, he may repudiate the license, cease to claim its protection, and as to his future exercise of the privileges described therein defend himself upon the ground that the patent is invalid. After such a repudiation of the license he may also dispute the validity of the patent in actions against him for license fees for the past making or use of the invention, but not for royalties on completed sales.3 When the license in its terms admits the validity of the patent, and provides that no act of either party shall impair the effect of this admission, the licensee cannot, at any time during the period for which the license was granted, attack the patent in his own defence. tion unless the license estops him, see Morse Arms Mfg. Co. v. U. S. (1880), 16 Ct. of Cl. 296. That although a patent may not be good for all it claims, a licensee taking its benefits cannot set up its invalidity in a suit against him for royalties, see Milligan v. Lalance & Grosjean Mfg. Co. (1884), 21 Fed. Rep. 570; 29 O. G. 367. 2 That a licensee cannot repudiate his contract without notice to his licensor, see Marsh v. Dodge (1875), 4 Hun, 278. That where a licensee has the right to terminate the license on a three months notice, and notifies the licensor of his present intention to terminate it after three months, this is sufficient notice, see Wilde v. Smith (1879), 8 Daly, 196. That a licensee, having repudiated his license with the knowledge of the licensor, may dispute the validity of the patent, see Brown v. Lapham (1886), 23 Blatch. 475; 27 Fed. Rep. 77; 37 O. G. 676; White v. Lee (1880), 3 Fed. Rep. 222; 5 Bann. & A. 572. That if the licensor repudiates the license, the licensee is not estopped thereby, see Baltimore Car Wheel Co. v. North Baltimore Passenger Ry. Co. (1884), 21 Fed. Rep. 47. 8 For the cases in which a licensee Neither an offer to take a can or cannot dispute the validity of the patent in actions for license-fees and royalties due before his repudiation, see §§ 1251, 1252, and notes, post. That a licensee is estopped to deny the validity of the patent, while the license is in force, if the license so provides, see Pope Mfg. Co. v. Owsley (1886), 27 Fed. Rep. 100; 37 O. G. 781; Magic Ruffle Co. v. Elm City Co. (1875), 13 Blatch. 151; 8 O. G. 773; 2 Bann. & A. 152. That if a licensee binds himself not to deny the validity of the patent, his only defence is that he keeps within his license, see Pope Mfg. Co. v. Owsley (1886), 27 Fed. Rep. 100; 37 O. G. 781. That a license is not affected by judgments in favor of third parties against the validity of the patent, if the licensee agreed not to dispute it, see Pope Mfg. Co. v. Owsley (1886), 27 Fed. Rep. 100; 37 O. G. 781. That where a license admits that the patent was lawfully granted, and provides that the revocation shall not impair the effect of this admission, the licensee is estopped to deny the validity of the patent, see Evory v. Candee (1879), 17 Blatch. 200; 4 Baun. & A. 545. That a licensee under a license ad |