History & Indochina: Alexandre Yersin — The Noble Adventure

Alexandre Yersin belongs to the rare group of Frenchmen whose memory is still honoured in today’s Vietnam. Discoverer of the plague bacillus, explorer, originator of the future mountain resort at Lang Bian (the city of Dalat), promoter of quinine and rubber plantations… Alexandre Yersin lived a full life — and saved thousands of others.

At the service of Doctor Roux and Pasteur in Paris, Yersin worked primarily on diphtheria. After four years of unrelenting effort at the laboratory on rue d’ULM and at the very Institute Pasteur that he helped bring into being, Yersin decided in September 1890 to embark for Indochina, to provide medical service aboard the small mail-boats of the Messageries Maritimes shipping company.

At that time, Cochinchina was one of the most unhealthy lands in the world. Infectious diseases rampant under the uniformly hot and humid climate were still poorly known and barely combated. Even Saigon, the capital — despite gradual improvements in city-planning — lacked basics: no reliable lighting, no ventilation, inadequate transport, rudimentary housing architecture, and primitive domestic life. Areas that later would become broad boulevards were then vacant, marshy lands.

Yersin spent several months on the Saigon–Manila line, then on the Saigon–Haiphong route. Around July 1891, he could not resist the urge to disembark at Nha Trang and make his way to Saigon by land.

The 500 km trek ahead of him was a real exploration. With only a compass, a marine chronometer, rope sandals and five tins of corned beef, he had ten days to reach Saigon before his boat departed. Exhausted and drenched, he eventually turned back. A few days later, a violent attack of malaria gave him the baptism of an explorer — and a colonial adventurer! The so-called “forest fever” at the time.

The First Mission

With support from his colleague Albert Calmette, Yersin embarked in March 1891 on an official mission to explore a little-known region of Annam — between the coast and the Mekong near Nha Trang. As barter, he carried cotton cloth, blankets, coloured handkerchiefs, nickel-plated knives, pipes, watch-chains, glass beads, small mirrored boxes, copper wire coils…

“As means of transport, I always recruited on site: elephants, coolies, ox-carts, or pirogues. This is one of the major difficulties of the journey, because a journey-leader will never take us beyond the next village — a perpetual source of delays and trouble.” Indeed, Yersin travelled alone and without escort, as peacefully as possible.

“My personnel consisted of three young Annamites from Saigon, of whom two followed me all the way to the end.” He set out on 29 March 1892 and, after two months of adventure, was welcomed by the French Resident in Cambodia. The expedition was a success — completing the work of the two great missions that had revealed Indochina to itself: the 1860 mission of Doudart de Lagrée and Francis Garnier, and the more recent mission of Pavie.

The Second Exploration

Backed by Pasteur himself, Dr. Yersin obtained permission to explore a region in southern Annam between the coast and the Mekong. He chose Bien Hoa as his point of departure. On the path from Tanh Linh to Phan Ri, he spotted the village of Rioung and a high mountain: Lang Bian. The Donnai River would have its source there. Through this he discovered the Lang Bian plateau.

With that vision — characteristic of all his undertakings — he had at the same time pinpointed where, one day, at Dalat, a highland resort for Indochina could be built. By 1897 the Governor-General, Paul Doumer, was considering establishing a hill-station where residents — weary from the climate and disease — could find rest, calm, and health. Yersin indicated the site. Thus the city of Dalat was born — destined for a brilliant future.

“I have already insisted on the precarious condition of the inhabitants, who are constantly exploited by the greed of the Annamite mandarins of Binh-Thuan or their servants. Trusting the formal promises of M. de Lanessan, I had promised the Mois that the protectorate would care for their fate. I believe it would be a fault not to honor that promise.” A few more days of walking brought him to the Bahnars — gentle, peaceful “savages” compared with their neighbours Djairais, Reulards, Sedangs, etc., described as true pillagers.

The Discovery of the Plague Microbe

After his third expedition, Yersin noted that the plague raging in Yunnan was threatening Tonkin and Annam. Urged by events, he finally traveled to Hong Kong. Since early 1894, a plague epidemic had devastated southern China, raging in Canton with more than 100,000 dead. The disease had reached Hong Kong, threatening all maritime trade routes. Panic reigned there: the city’s appearance had changed — streets deserted, the harbour almost empty.

Walking through the city, one saw numerous dead rats littering the ground. Houses affected by the epidemic were isolated; the most contaminated neighborhoods were sealed off. Yersin observed that the European population had been relatively little struck by plague. Why? Because Europeans lived in far more hygienic conditions than the Chinese.ques très supérieures au mode d’existence des Chinois.

Despite difficulties in performing autopsies, Yersin quickly isolated the plague microbe by examining the buboes on the corpses. He also established the mode of transmission: rats. In three weeks, he identified the plague bacillus — the bacillus “of Yersin”!

(Source — excerpts from Noël Bernard, Yersin, 1863–1943)