The Metropolitan Board of Works, and (subject to the Provisions herein contained) the Board of Works for every District under this Act, and the Vestry of every Parish mentioned in Schedule (A.) to this Act, shall respectively appoint or employ, or continue for the Purposes of this Act, and may remove at pleasure, such Clerks, Treasurers, and Surveyors, and such other Officers and Servants as may be necessary, and may allow to such Clerks, Treasurers, Surveyors, Officers, and Servants respectively such Salaries and Wages as the Board or Vestry may think fit.