¶1delivered the opinion of the Court.
¶2It is undisputed that Homer Potwin, the landlord’s agent, in renting the premises and collecting the rent therefor, knew when so collecting the rent that the house was being used by the tenants for gambling purposes. We are of the opinion that when, as his mother’s agent, he leased the rooms, he knew that they were to be used for the purpose of gambling.
¶3His knowledge in this respect, that is, the knowledge which, as her agent to let these premises and collect the rent therefor, he derived in the course of so acting, is to be imputed to her. Mecham on Agency, Sec. 718.
¶4The testimony of Webb, as to his conversation with her, shows that she then knew that he was using the premises for gambling purposes. She fails to appear as a witness and deny her knowledge of the illegal use for which her premises were let and used; the testimony of Webb should, therefore, in this action, be conclusive against her as to her knowledge that the defendants below were then using her house for the purpose of gambling.
¶5Such continued use, coupled with her connivance thereat and aid thereof, in suffering her son and agent to set off his losses in gambling at such place, against the rent due her, is a defense to this action for rent. Wood’s Landlord and Tenant, Sec. 551; 21 Com. Law, 744; Jennings v. Throgmorton, Ry. & M. 251.
¶6After the commencement of this action, the rent for the month of December, 1894, became due. Suit was brought by the defendant in error, and a judgment therefor recovered by her. The files and records in that case were introduced in evidence on the trial of- the present case, as an estoppel against the defendant below—preventing them, it is said, from urging the defense of illegality in the renting or use of the said premises.
¶7“ The estoppel of a judgment extends only to the question directly involved in the issue, and not to any incidental or collateral matter, though it may have arisen and been passed upon.” Lewis’ Appeal, 67 Pa. St. 153; 21 Am. & Eng. Ency. of Law, 192.
¶8“ In all cases, therefore, where it is sought to apply the estoppel of a judgment, rendered upon one cause of action, to matters arising in a suit upon a different cause of action, the inquiry must always be as to the point or question actually litigated and determined in the original action, not what might have been thus litigated and determined. Only upon matters actually litigated is the judgment conclusive in another action.” Cromwell v. Sac Co., 94 U. S. 351.
¶9The only question, so far as the record shows, actually litigated by the suit in which the judgment was obtained, was whether the rent for December, 1894, was due and unpaid.
¶10A decision as to what the premises were used for during months other than December, 1894, was not necessarily involved in the suit brought for the rent of that month only.
¶11The estoppel of a judgment is limited to matters necessarily involved in the litigation in which the judgment is rendered. Atty. Gen. v. C. E. R. R. Co., 112 Ill. 539.
¶12The burden of proof was upon the defendant in error, she setting up the judgment, to show what was determined by it, and failing to do this, the court can only look to the bare judgment to see what was of necessity determined in that suit. 21 Am. & Eng. Ency. of Law, 202.
¶13“ If there be any uncertainty in a record, if several distinct matters may have been litigated, upon one or more of which judgment was rendered, the whole subject-matter of the action will be at large and open to a new contention, unless the uncertainty be removed by extrinsic evidence showing the precise point involved and determined.” Russell v. Place, 94 U. S. 606; Davis v. Brown, 94 U. S. 423.
¶14The judgment of the Circuit Court is reversed and the cause remanded.