(b. Aubonne, near Lausanne, Switzerlaqnd, 23 September 1863; d. Nha Trang, Annam, Vietnam, 1 March 1943)
Yersin received his secondary education in Lausanne before entering the Academy there; he subsequently attended the University of Marburg and the Paris Faculty of Medicine. Having cut himself while performing an autopsy on a patient who had died of rabies, Yersin immediately contacted Émile Roux, one of Pasteur’s most brilliant pupils, who gave him an injection of a new therapeutic serum that saved his life. This incident brought Yersin into close contact with Roux, who hired him as his assistant in 1888 and with whom he conducted research on rabies. He then worked with Robert Koch, in Berlin, collaborating with the noted microbiologist in his research on the tubercle bacillus. Upon his return to Paris, Yersin began his own research with Roux, at the Institut Pasteur, on the toxic properties of the diphtheria bacillus. In 1889, however, he suddenly embarked as ship’s doctor on a steamer bound for Saigon and Manila. He returned to Paqris and left again for Indochina; and during three dangerous expeditions into the interior, he discovered the high plateau of Langbiang, where he founded a small colonial village. The area soon became a vacation center for Europeans, and the city of Dalat was developed there. In 1935 the municipal authorities established the Lycee Yersin at Dalat.
In 1894 Yersin became a medical officer in the French colonial service and conducted research on the bubonic plague epidemic that was sweeping through China, in orde, to determine the measures that should be taken to prevent its spread into Indochina. At a small bacteriological research laboratory, set up for him in Hong Kong, he discovered the plague bacterium, practically at the same time that Kitasato did so independently; and after much work he isolated an effective serum. In 1904 he was recalled to Paris and continued his research at the Institut Pasteur, of which Roux had become director. With Albert Calmette and Amédée Borrel he made the important observation that certain animals can be immunized against the plague through the injection of dead plague bacteria. He then returned to Nha Trang, where a branch of the Institut Pasteur had been established under his direction. There, in modest laboratories, Yersin perfected an antiplague serum that made it possible to reduce the death rate from 90 percent to about 7 percent.
With the assistance of Paul Doumer, then governor-general of Indochina, a medical school was founded at Hanoi; Yersin directed this center of study and research for many years. Through Yersin’s work Indochina was able to control the epidemics that beset the country, especially malaria. In recignition of his medical achievements, the French government appointed Yersin honorary director of the Institut Pasteur.
Besides his activity in science and medicine in Indochina, Yersin conducted research in agronomy. His interest in the cultivation of grains and in soil conditions led him to intiate a series of ecolog ical studies . He also reflected on the natural history of Indochina, having become fascinated by the flora and fauna of his adopted country. Yersin became deeply concerned over the needs of the sick and the poor and fought hard against the exploitation of the lower classes.
I. Original Works. Yersin’s dissertation for the M.D. at Paris is Sur le developpement du tubercule experimental (Paris, 1888). Most of his papers were published in Annales de l’lnstitut Pasteur ; they include “Contributions a (’etude de la diphterie,” 2 (1888), 629-661; 3 (1889), 273-288; and 4 (1890), 385-426, written with Émile Roux: “La peste bubonique a Hong-Kong,” ibid., 8 (1894), 662-667: and “Sur la peste bu-bonique: Séerotherapie.” ibid., 11 (1897). 81-93.
11. Secondary Literature. See N. Bernard. “A. Yersin (1863-1943).” in Annales de l’Instinu Pasteur, 69 (1943). 129-134, with portrait: N. Bernard. P. Hauduroy, and G. Olivier, Yersin et la peste (Lausanne, 1944): H. Buess, Recherches, decourertes et inventions de nude cins suisses (Basel.1946) :and P. Hauduroy. “Les decouvertes de Yersin et les methodes pastoriennes.” in Sclnre i:erische mcdi,inische Wochen-schrift, 24 (1943), 750-751.
P. E. Pilet