Printed 'On His Majesty's Service' official envelope franked with 1935 1d grey & carmine and 1/- brown & chalky blue and 1947 2d slate & deep lilac 'OFFICIAL / OFFISIEEL' overprint issues (SG O21, O25 & O36) tied by TZANEEN cds dated OCT 1952. Sent airmail to 'E. J. Pampana, Secretary, Expert Committee on Malaria, World Health Organisation, Geneve, SWITZERLAND'.