Power to issue commission for examination of witness in prison.

    The provisions of this Chapter shall be without prejudice to the power of the Court to issue, under section 284, a commission for the examination, as a witness, of any person confined or detained in a prison; and the provisions of Part B of Chapter XXIII shall apply in relation to the examination on commission of any such person in the prison as they apply in relation to the examination on commission of any other person.