The county collector, in all counties of the second class, shall be entitled to have and to appoint such deputies and assistants as the county collector, with the approval of the county commission, shall deem necessary for the prompt and proper discharge of the office, and such deputies and assistants, so appointed, shall receive such salaries as may be fixed by the county collector, 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 collector is paid.