And be it enacted, That One of Her Majesty's Principal Secretaries of State shall fix the Number of Clerks, Ushers, Door-keepers, and Messengers to assist in carrying on the Business of each or the said Courts, who shall be appointed, and may be dismissed at Pleasure, by the Secretary of State; and the Clerks now acting at the said several Offices shall be continued the Clerks of the said Courts during the Pleasure of the Secretary of State; and no Person shall hereafter be appointed Chief Clerk in any of the said Courts unless he shall be an Attorney of One of Her Majesty's Superior-Courts of Law at Westminster, or shall have served as Clerk in One or more of the said Police Courts or Offices, or as Clerk to the Justices of any Division or Special or Petty Session within the Metropolitan Police District, during at least Seven Years ; and no Clerk in any of the said Courts shall hold or have any other Office or Employment whatsoever, except any Office or Employment to which any such Clerk has been appointed before the passing of this Act with the Sanction of the Secretary of State ; and every Usher, Door-keeper, and Messenger appointed to any of the said Courts shall be sworn as a Constable, but shall only be empowered to act as a Constable within the said Courts and the Precincts thereof, unless for the Protection of the Magistrates or of Persons resorting to the Court, or, in case of being sworn in as Special Constables, in any urgent Necessity in which the Services of any One or more of them may be specially required by an Order in Writing from the Secretary of State.