US SUPREME COURT DECISIONS

In all cases of concurrent jurisdiction, the court which first has possession of the subject must determine it conclusively.

Although courts of equity have concurrent jurisdiction with courts of law in all matters of fraud, yet where the cause has already been tried and determined by a court of law, a court of equity cannot take cognizance of it unless there be the addition of some equitable circumstance to give jurisdiction.

In such a case, some defect of testimony or other disability which a court of law cannot remove must be shown as a ground for resorting to a court of equity.