The county treasurer of a county of the first class not having a charter form of government, and of a county of the second or third class shall be entitled to have and to appoint such a number of deputies and assistants as the county treasurer, with the approval of the county commission, deems necessary for the prompt and proper discharge of his office, and the treasurer’s deputies and assistants shall be paid such salaries as are fixed by the county treasurer with the approval of the county commission. The salaries of all such deputies and assistants shall be paid by the county in the same manner as the salary of the county treasurer is paid.