On or before the return day of the process either party may demand a trial by jury, and thereupon the justice of the peace shall order the proper officer to summon six persons, competent to serve as jurors in the circuit court, to appear immediately, or at such early day as he may appoint, whether at a regular term or not, who shall be sworn to try the case; but each party shall be entitled to challenge peremptorily two jurors, and as many more as he can show sufficient cause for. If a sufficient number of jurors shall not appear, others may be summoned until a jury is made up, to consist of six, against whom legal objections shall not exist. If the jury fail to agree, it may be discharged and another jury summoned, and so on until a verdict is obtained, and judgment shall be entered by the justice on the verdict.