Section 18. A justice, special justice acting in the place of the justice, clerk or assistant clerk of a district court shall not receive any fee or compensation to his own use, other than his regular salary or allowance, for making complaints or issuing in any capacity warrants, subpoenas or other criminal processes which he is authorized to issue, or for any official services performed by him in court. A clerk or assistant clerk shall not receive, in addition to his salary, any fee or compensation for making out bail papers, or for admitting a prisoner to bail while the court is in session or during the hours when his office is required to be open.