Iowa (D) was an Iowa State corporation. Baldwin (P) sued D and D appeared by special appearance to quash service and dismiss for want of service. That motion was overruled and D decided not to file a plea, and the case proceeded to judgment. D never moved to set aside the judgment, to sue out a writ of error, or even to appeal. P went to enforce the judgment in Iowa, D pled lack of jurisdiction, that defense was sustained, and the case dismissed. P objected to proof of these matters, asserting that the defense constituted a collateral attack and a retrial of an issue settled in the first suit. P appealed an adverse judgment.