Any circuit court heretofore authorized by special act of the Legislature to appoint a law clerk or law assistant shall continue to have such authority, and all of the provisions of any such special act or any other special acts amendatory thereof shall continue to apply, and any such law clerk or law assistant shall receive the salary most recently authorized in any such special act, until changed by such circuit court, with the approval of the Supreme Court of Appeals, by order entered of record, but such salary shall be paid out of the State Treasury.