That amendments may be allowed by the court after issue and at any time before final decree, when it is manifest that the purposes of substantial justice require it, is admitted. But while it is thus admitted that the courts have such authority in the use of a sound discretion, they must be very cautious in its exercise. When the object is to let in new facts and defences wholly dependent on parol testimony, the reluctance of the court is greatly increased.
As the bill in this case was filed to the last term, and as the application for leave to amend was first made before the testimony was taken, it is not subject to the charge of laches, or great delay. The defendants have sworn also that the matters and things set forth and contained in the said proposed amendment only recently came to their knowledge, and subsequently to the filing of their said answer. This can only refer to the last matter of amendment, to wit, the invalidity of the patent. As to the first and second.' there is no allegation or proof of any mistake of fact or law in the answer first sworn to, or that the extent of their infringement was not as well known before as since the answer was sworn to. These amendments cannot ;be allowed.
The only question, therefore, is, whether the respondents should now be allowed to set up a matter of defence inconsistent with .their first answer. Assuming their answer and affidavit to be true, the ease stands thus: They ’ purchased a patent right from the patentée; supposing they had obtained a valid patent: .-they make defence to the complainants’ bill, ■alleging a previous purchase: after filing their answer, they discover that the patent is invalid and their title to it good for nothing. Why should they not he allowed to contest the validity of the patent, and show that the . complainants, as well as themselves, have been defrauded by the patentee? For if, under such ■ circumstances, the respondents should be enjoined from using the supposed invention, it would present this anomaly, that the respondents would be hindered from using that which belongs to the whole world. Under the peculiar circumstances of this case, ive think it would not be an abuse of the sound discretion of the court to permit the respondents to file a supplementary answer setting up this defence, on payment of costs which have accrued on the abandoned de-fence: 1st. Because there has been no lach-es or delay, the application being made during the term to which the bill was filed. 2d. The application was made as soon as the fact was discovered, and before any testimony was taken. 3d. If the defence be true, as we now assume, although the defendants might have discovered it before by proper diligence, yet believing their title to the patent better than that of complainants, their attention was not called to contest its validity till they discovered the invalidity of the title which has been imposed on them by the pat-entee. 4th. There is nothing contradictory or inconsistent between the answer as filed and the amendment proposed to be made: The first was made under the supposition that the patent, as well as the respondents’ title to it, were valid. The new discovered defence admits they were doubly wronged by a bad title and by a worthless patent.
Whether this defence can be satisfactorily established is the matter to be tried.
iNOTE. There was a decision in this case in favor of complainant. Case No. S.413. It was subsequently heard upon motion to treble the damages. Motion refused. Id. 8,414. The decree of the circuit court was for perpetual injunction and awarding $13,282.92 damages for infringement. From this decree an appeal was taken to the supreme court. The injunction was modified, and one dollar nominal damages awarded. 1 Wall. (68 U. S.) 155.]