By setting the plea down for argument the complainant tests its sufficiency, and, in effect, demurs to it. Myers v. Dorr, 13 Blatchf, 22; Cattle v. Krementz, 25 Fed. Rep. 494; Newton v. Thayer, 17 Pick. 129; Walk. Pat. § 590; Daniell, Ch. (5th Ed.) 692; Story, Eq. Pl. (9th Ed.) § 697; Mitf. & T. Eq. Pl. 389. The issue tendered by the plea-is whether or not the defendants infringe the claim of the patent construed in connection with the specification, the file wrapper, and contents, and in the light of the prior art. This is the controversy which usually arises when the defendant denies that he makes, uses, or vends the patented device. In other words, the defendants seek to try the question of infringement upon a plea. It is clear that there is no authority for such practice. If the question were now considered by the court, and decided against the defendants, they could allege the same defense in their answer and try the entire issue again. It is not the province of a plea to interpose defenses which go to the merits and relate in nowise to matters in abatement or in bar. Such defenses should properly be raised by answer. Sharp v. Reissner, 9 Fed. Rep. 445; Rhode Island v. Massachusetts, 14 Pet. 210.
The defendants cite in support of their plea, Hubbell v. De Land, 14 Fed. Rep. 471; but in that case the court, at page 474, says: “Argument can hardly be needed to show that the question of the infringement of a patent is not the proper subject of a special plea.” In the case at bar, where the device is a simple one, and the issues are sharply defined and easily understood, it is possible that the question of infringement might be satisfactorily determined in this manner with a saving of expense to all parties concerned. But a decision once made to this effect will be “recorded for a precedent,” which may be invoked in every action of infringement, and thus tend to unsettle and confuse what is now plain and simple.
'filie jilea is overruled, the defendants to answer in 20 days.