Laos. (French Indo-China). 1917. Registered and Advice of Receipt envelope headed 'Assistance Medicale du Laos/ du Tran-Ninh, Laos' addressed to France bearing French Indo-China SG 55, 10c scarlet (block of four) tied by Xieng-Khouang/ Laos double ring '1st Oct 1917' with circular 'Indo-Chinese Francaise/ Laos/ Service de Sante/ Xieng Khoung/ Le Medecin de L' Ambuance' in violet on face with boxed 'R' and hand-struck 'A.R.' on face routed via Vinh/ Annam. Superb item of Advice of Receipt mail from Upper Laos