The names of jurors shall be publicly drawn by the jury commission from a jury box containing the names of not less than 100 qualified persons at the time of each drawing. The jury box shall be filled and from time to time refilled by the jury commission. The jury commissioners and the clerk, or his deputy, shall alternately select and place in the jury box the names of qualified persons of intelligence, sobriety and integrity, and without reference to their political affiliations or opinions, until the jury box contains the names of at least 100 persons or such larger number as the court determines.