Out of the jurors appearing upon such summons a jury of thirteen persons shall be drawn by ballot; and if a sufficient number of jurymen do not appear in obedience to such summons the sheriff shall return other indifferent men, duly qualified as aforesaid, of the bystanders, or others that can speedily be procured, to make up the jury to the number aforesaid; and all parties concerned may have their lawful challenges for cause against any of the jurymen; and each party may have three peremptory challenges.