4. Matrimonial jurisdiction of High Courts to be exercised subject to Act. Exception.- The jurisdiction now exercised by the High Courts in respect of divorce a mensa et toro, and in all other causes, suits and matters matrimonial, shall be exercised by such Courts and by the District Courts subject to the provisions in this Act contained, and not otherwise: except so far as relates to the granting of marriage- licenses, which may be granted as it this Act had not been passed.