Gray (P) alleged that Titan (D), an Ohio corporation, negligently constructed a valve which it sold to American (D1). D1 put that valve in a water heater. D1 manufactured its product in Pennsylvania and sold the water heaters in various states. P was injured when her heater exploded. P lived in Illinois. P alleged that D's negligence caused the explosion. The explosion occurred in Illinois. D did no business in Illinois and had no agent there. The state Civil Practice Act provided for service of a nonresident who either in person or through an agent committed a tortious act within the state. P sued both Ds. D1 then filed a cross-claim against D. D was served in Ohio under the Civil Practice Act. D then moved to dismiss both the complaint and the cross-complaint. That motion was granted, and P appealed to the Supreme Court of Illinois.