The said board shall within 15 days after the adoption of this act in any city make a list of persons to serve as jurors in said court for the remainder of the then calendar year, and shall during the month of November of each year thereafter make a list of persons to serve as jurors of said court for the next succeeding calendar year: Provided, That the failure to complete said list during the period specified shall not affect the validity of the list thereafter made by said board. Each of said lists shall be of jurors equal in number to 1 for each 500 inhabitants in the city, computed according to the last preceding census: Provided, That in no case shall it be necessary to make a list of more than 300 persons. If before the end of said calendar year the judge of a police court shall determine that additional names are necessary, he shall order said board to make another list of persons in such number as he shall determine to serve as additional jurors for the remainder of such calendar year, and it shall be the duty of said board to make such list.

     Said board shall make such lists in duplicate and file 1 in the office of the city clerk and 1 in the office of said court.