Opinion of the court by

Bennett brought his suit against Martin in the circuit court; and the judgment there being in favor of the defendant, Bennett prosecutes this writ to reverse ihat judgment.

The plaintiff declared on a bond, made to him by Martin for the payment of five hundred dollars. The defendant pleaded in bar that the bond was given in consideration of the right and privilege of a certain supposed patent right existing under the United States, called and known as Stag-ner’s Patent Truss for curing the Hernia; and that the defendant did, to secure the payment of the said sum of money, make, execute and deliver the said writing obligatory and for no other consideration, and avers that at the time when the plaintiff' sold to the defendant the said privilege and right of using the said supposed patent right as aforesaid, the said supposed patent was, and ever since have been and still is, void in law, and of no effect or validity whatever. To this plea the plaintiff replied, denying that his patent was void. An issue was made and the plaintiff gave the bond in evidence. The court, on motion of the counsel for the defendant, instructed the jury, that the plaintiff had not made out his case, and that they must find for the defendant.— Upon this, the plaintiff took a non suit, with leave to move to set it aside. This motion was oyer ruled by the circuit court.

This plea admits the existence of a patent, but denies its yalidity. If the counsel for the defendant had desired to J test the validity of the patent, then they should have pleaded, that there was no such patent, and on the production the instrument in court by the plaintiff, the defendants counsel might have given in evidence, any fact which would ren-*462^61' *ustrument vo^ ™ ^aw< Framed as the plea is, the law is left to be found by the’ jury. The plaintiff ought to have demurred to this plea.

The judgment of the circuit court is reversed and the causéis remanded for further proceedings, and the defendant, if he wishes, will be allowed to withdraw his plea and plead again,