¶1delivered the opinion of the. court.
¶2This is an action ex contractu. The theory of an action is to be ascertained from the written statement of his demand solemnly made by a party in court. When a party deliberately takes a position in court then an estoppel arises which prevents him from changing his position after the termination of that suit, whether the result therein is in his favor or against him. The legal effect of Pluard’s statement of his demand in this case is an assertion that John J. Gerrity and Peter J. Gerrity, the defendants, jointly undertook and promised him to furnish steam heat and hot water and that they did not carry out and perform their joint promise in that behalf. The judgment was rendered by the learned trial judge on the theory of a joint obligation. In the evidence, however, there is not even a pretense or a suggestion that Peter J. Gerrity joined in any promise or undertaking with reference to furnishing steam heat and hot water. In an action against two or more, ex contractu, it must appear from the evidence that there was a joint contract, by all the defendants, otherwise there can be no recovery against anyone. For authorities see cases cited in Heidelmeir v. Hecht, 145 Ill. App. 116; The Cairo & St. Louis R. R. Co. v. Easterly, 89 Ill. 156, 158; Faulk v. Kellums, 54 Ill. 188; Cooper v. McNeil & Higgins, 43 App. 350. This rule applies to actions prosecuted before justices of the peace, where there are no pleadings. Briggs v. Adams, 31 Ill. 486. The rule, as specifically pointed out in some of these cited cases, is founded in sound reason and is one of substantive law, not merely one of practice. No one should in court be required to defend against a cause of action other than that wherewith he has been charged. Other errors appear in this record but it is unnecessary to discuss them. For the error in rendering judgment herein without any evidence tending to show liability on the part of Peter J. Gerrity the judgment is reversed and the cause remanded.
¶3Reversed and remanded.