Jury trial as guaranteed in general terms means a determination of questions of fact in cases tried at law, either civil or criminal (as distinct from civil cases tried in equity), by a jury of twelve qualified persons selected, in accordance with legal methods, for the particular case and constituting for the time being a part of the machinery of the court to find the ultimate facts, and under the instructions of the judge as to the law render a general verdict which has received the unanimous approval of the twelve jurors, which verdict determines the case as between the parties and furnishes the basis for a judgment in favor of one party against the other to be rendered by the court. The essential features of this form of trial are numerous and they cannot all be elaborated here; but briefly they are as follows.

By some suitable means of procedure twelve persons are secured for the trial of the particular case; they are usually required to be citizens of the state or United States, as the case may be, possessing full mental capacity and in the enjoyment of the faculties of seeing and hearing so that they may rightly and fully comprehend the evidence presented to them. It is usually required that they be selected from the class of persons who are entitled to exercise the elective franchise, but there is no necessary connection between the right to vote and the capacity to serve as juror.

Some classes of persons are as a matter of public policy exempted from the obligation to serve on juries, such exemptions usually extending to physicians, lawyers, teachers, and public officers whose business or public duties are such as to be seriously interfered with to the public detriment if jury service is required of them. It is left discretionary with the court to excuse in particular instances other persons who by reason of some special emergency would be unreasonably inconvenienced or damaged by such compulsory service; but mere interference with ordinary business or occupation is not regarded as just ground of excuse, for the citizen can be properly required to perform his public duties without regard to the effect upon his private interests.

A juror to be qualified to sit in a case must be, however, not only generally qualified to discharge such duty, but he must also be qualified with reference to the particular case in which he is to sit; that is, he must be substantially without bias or prejudice which would be likely to interfere with his rendering a fair and impartial verdict. Therefore one who has formed or expressed an opinion as to the merits of the case, or is so related to one of the parties that he is likely to be predisposed to favor him, or who occupies a position of hostility towards one of the parties which would predispose him to a decision hostile to such party's interests may properly be excluded. The general and special qualifications of each particular juror are inquired into, and if for any reason he appears to be disqualified the party desiring that he shall not serve as a juror in the trial of the case interposes a challenge for cause, and if the judge considers the objection to be well taken such person is not selected as one of the jurors.

There may be special reasons why a person called as a juror would not be likely to render a fair verdict in a case between the parties, other than the general reasons just suggested, and it is usually provided that each party shall have a number of so-called peremptory challenges which he may exercise for the purpose of excluding such persons from the jury as he desires to object to, although no legal reason for such .exclusion is given. When twelve persons are secured against whom no valid objection is found to exist and to whom no peremptory challenge is interposed, these twelve persons are sworn to render a fair and impartial verdict in the case'and become the jury for the trial.