This was a bill to foreclose a mortgage alleged to have been made to appellee by Marshall Stailt, as conservator of Mary Ann Schmidt, by virtue of an order authorizing the same made by the County Court of De Kalb county.

The defense seeks to question the validity of the appointment of the conservator, and the record discloses the fact that the jury which found Mrs. Schmidt non compos mentis was composed of but six men, and therefore, appellants insist, the ap lointmentof the conservator which followed as a result of the finding was unauthorized, the whole proceedings were void, and can be attacked in this collateral proceeding. We can not assent to this view of the case. The county court, at the time of the alleged appointment, had jurisdiction of the subject-matter and of the person of appellant, and the very question now sought to be raised in this collateral proceeding was passed upon and considered by the court. It became the duty of that court to determine the question of the number required to constitute a jury, as well as all other questions piroperly arising, and whether the court erred in any of those questions or conclusions, can not be inquired into in a collateral proceeding of this kind.

Jurisdiction has been thus defined: The power to hear and determine a cause is jurisdiction. It is c-oram judice whenever a case is piresented which brings this power into action.

The county court, after having once obtained jurisdiction over the subject-matter and the pierson of appellant, would not lose it, no matter how erroneous its proceedings.

We think the case of Dodge, Conservator, v. Cole et al., 97 Ill. 338, conclusive upon the point.

The decree of the circuit court will he affirmed.

Affirmed.