Opinion by

We do not understand the position assumed by counsel to be a correct rule of pleading, but, on the contrary, directly in conflict with the practice, as well as all the rules of pleading. Where a cause of action is defectively stated, as in the failure to allege that a party of unsound mind was in that condition on the day the writing sought to be cancelled was executed, and the defendant by answer denies that he was of unsound mind on the day and at the time he signed the writing, this last pleading has made an issue for the plaintiff that he himself should have made, and cures the defect. The pleader, when his petition is defective, should never demur to the answer for the reason that the demurrer goes back to the petition unless the answer has made the petition good.

In this case, if the answer had been defective, the plaintiff should have demurred because, although the answer is bad, the petition is cured by it. Where the petition is bad, and the defense is desirous to experiment with the case in order to see what the court or judge will do with his client, it is best not to demur, but to traverse the petition with an answer that is no better than the petition; and if the case is lost a motion to arrest the judgment must prevail. It is *433true, the good pleader dislikes to file a badi plea, but if he prefers pleading over, the result is that the petition is made good. If the petition is defective the defendant must stand by his demurrer to avail himself of the defect in the declaration, or file a plea that is no better than the declaration, or be careful not to aid the original pleading. If he cures the defect by pleading over, his demurrer amounts to nothing. It is true there are some petitions in which matters of substance are failed to be alleged that cannot be cured by plea or answer; but such is not the case in the pleading before us. The demnurrer was before us when the case was considered. The petition is overruled.