Jurisdiction is the power to hear and determine a cause.24 Courts can take jurisdiction only as authorized by the constitution and statutes, not even by the consent of the parties where the law does not give the court jurisdiction of the subject-matter.25 Hence, the accused cannot waive a jury in a felony case, nor can he waive an indictment - for the reason that these are questions going to the jurisdiction of the court.26

34 Kelly vs. People, 115 Ill, 589.