Yersin is the youngest child in family with three siblings
Yersin’s father is a Swiss man, and Biology teacher at Monges high school. He likes researching entomology. He died three weeks before Yersin was born. Yersin’s mother is a French; her hometown is in Paris.
At the age of 20, Yersin studied Medicine in Lausanne (Switzerland), and then Yersin continued to study in Marbourg and graduated from Paris University with medical PhD thesis in tuberculosis.
From 1886, Yersin worked in Pasteur Paris institute and Yersin co-operated with doctor Roux to find out toxin of bacteriology diphtheria.
In 1889, Yersin adopted the French citizenship.
In years’ researching in Pasteur Paris Institute, Yersin proved to be an extraordinary genius, energetic, clever, thirsty for knowledge. A bright future was opened up for Yersin, but Yersin directed himself toward a new horizon, wanting to find out an escape from the real life: “ I always desire to explore, to discover an unknown land; when we are young, we always imagine strange things to appear, and nothing is impossible to do”
Thus, in 1890, Yersin suddenly temporarily left his work on microbe, living the life of sailor and explorer, starting with new life which extended over 50 years.
Firstly, Yersin was a doctor on a ship of sea transport to the Far East. After six months Yersin worked on Sai Gon – Ma-ni-la, he transferred to work on the ship "Saigon" travelling from Saigon to Haiphong and vice versa.
In the first trip to see Nha Trang, its landscape fascinated Yersin’s soul. Yersin intended to go by road from Nha Trang to Saigon by going west until the Truong Son range first, then go west to the south to Saigon. Yersin intended to make the trip across the mountains which were completely unknown for 10 days, in order to have enough time to get back to his ship before the ship left for the Hai Phong
One day in July 1891, the ship came to Nha Trang. Yersin came to see Mr. Lenormand - Marine officer, the mission of Khanh Hoa province – who was living in a cottage on the coast, near a fishing village. He was very interested in the intention of Yersin and was willing to help him and asked the officials of the Dien Khanh to find a guide for Yersin. But no one here took risk to go up the Truong Son range, a mountainous region regarded as sacrosanct! Lenormand recommended Yersin to change his mind and continue to take the large road to Phan Rang, where there might have trails to Truong Son.
Yersin rode a horse on the road which was just a trail at that time and went to Phan Rang in the shortest time. Previously, to avoid religious persecution, a missionary priest in Phan Rang escaped to the high land in the western mountains. This missionary priest just remembered about his escape to the high land and recommended Yersin to continue the journey to Phan Ri, as Yersin would certainly find a guide there to the mountains.
Yersin continued to Phan Ri. The local staff found immediately for Yersin the one who knew the roads deep into the Truong Son range. Yersin could not wait until the next day, he and his guide departed in the middle of the day.
Finally, they went to Djiring (Di Linh today). Villagers said they could continue the journey to Saigon, but it took at least from 9 to 10 days on the road. In two days, the ship left for the North, Yersin could not continue, he had to go to the coast immediately. Yersin knew that Phan Thiet was a nearest location, which it just took a day to get to.
The next night, Yersin came to Phan Thiet. At a duty station, Yersin was cordially welcomed. The head of the station gave Yersin a pair of boots for him to replace the old shoes which were worn out since he reached the top of the pass. Yersin was on a sailboat in Nha Trang and came to Nha Trang’s duty station in Chut.
That night, the "Saigon" ship also arrived at Nha Trang, Yersin was on board on time when the ship was going to head to Quy Nhon.
Arriving at Haiphong, Yersin suffered malaria which lasted throughout the time the ship stopped at this port.
In 1892, Yersin departed from Ninh Hoa to Dak Lak
On 9th, June 1892, Yersin came to Stung Treng on the Mekong River.
After a period of time living in Paris, Yersin hoped to continue to explore, he wrote in his diary:
When I came back to the civilized life, I quickly forgot tiredness, hard work, and shortage of necessities in the expedition. But then I missed the adventurous life full of the unexpected things, and there are few explorers to be satisfied with the first expedition. I am not excluded from this rule. I managed to find ways to conduct a new trip with the science mission after I had recovered from dysentery during a trip in 1892.
Thanks to the help of my brilliant teacher, Pasteur and Minister of Education, on 24th December 1892, I left the port of Marseille for Saigon. The trip was primarily to explore a region of Nam Trung Ky (Southern Central Vietnam), which was located between the coast and the Mekong River, on the upstream of the Dong Nai River and Xe Bang Can.
When I had just arrived in Saigon, I came to present me with Governor-general. Mr. De Lanessan wanted my journey to achieve practical results. He wanted to continue in the Trung Ky the work he had started to do in the Bac Ky (North Vietnam), and he planned to build more roads to help transport system become easy, to allow them to move further inland, to make commerce more convenient and to expand the sphere of influence.
He let me research a project of roads which was from Saigon to Thuong ethnic group’s region. This road will go to the North to come to the most convenient location on the coast of Central Vietnam.
I had to present the current status of the resources of this country, the possibility of livestock, forest products research, searching of minerals exploitable in the mountains.
In 24th, February 1893, Yersin went to from Saigon to Bien Hoa, the Vietnamese also used the sampans to carry luggage up the river.
On February, 28th, the delegation rode a buffalo cart from the Tri An to Tra Cu
On 18th, March, Yersin continued to go to from Tanh Linh to Phan Thiet.
From Phan Thiet, Yersin went on the road to Nha Trang to present himself before the mission Lenormand and then he returned to Phan Ri
On April, 8th , from early morning, the delegation consisted of 80 porters, six horses, an elephant, which departed on the mountain. The delegation went to from Kalon-Madai (Binh Thuan province) to Riong (Lam Ha district, Lam Dong province today) on April 14th. If Yersin continued to go to the Northeast, Yersin was going to Lang Biang Plateau, but Yersin returned to Tanh Linh and transferred the Lang Biang reconnaissance to later time.
On May, 22nd the delegation went along La Nga river valley, crossing the Da Dong river to the Ta Dung mountain (Dac Nong province). After climbing Ta Dung, Yersin came to Con Tan and Riong. Yersin left his things in Riong, and with four porters made the reconnaissance of Lang Biang.
At 3. 30 pm on 21st, June, 1893, Yersin came to the Lang Biang Plateau. Yersin only stayed one night in Dang Kia, and then returned to Riong in a heavy rain.
Leaving Riong, Yersin went along the river valleys of Da Nhim and came to Phan Rang.
At the end of 1893, Yersin went back to Lang Biang Plateau, he made a reconnaissance of Dak Lak Plateau , A-to-po (Laos) and on 7thMay, 1894 he came to Da Nang.
In 1890, Dr. Albert Calmette established a branch of Pasteur Institute in Saigon.
In 1894, the plague spread all over Eastern China. Dr. Calmette proposed Yersin to come to China to study the plague on the spot
On 15thJune1894, Yersin came to Hong Kong and met an opponent - Dr. Kitasato , who had got to Hong Kong three days before Yersin. This Japanese doctor was famous for his scientific work to find out the germs of tetanus.
Yersin built a thatched hut next to the hospital and worked in a deprived condition. After only five days of work, in 20th , June, 1894, he found the germs of plague. Through the British postal system, he sent the containers of bacillus to France. When the containers of bacillus were at the Paris Pasteur Institute and they were verified, called Yersin (Yersinia pestis).
In 1895, Yersin established Pasteur Institute in Nha Trang and prepared serums for the treatment of plague.
After a year , the plague was relapsed in China, Yersin came back to China and saved many people from this plague, which had killed 50 million people since ancient times. .
Yersin returned to Nha Trang. A new life was begun. Many problems were posed.
Yersin realized that Nha Trang city was built on a sandy area, which was not convenient to expand the pastures to feed the horses, which were used to prepare serum, he explored Suoi Dau region, which was over10 km from Nha Trang to the south; he established a ranch and farming.
Following the example of his predecessors, he engaged himself in research on serum for therapy plague of cattle. Since then, Nha Trang Pasteur Institute researched on bacteria of animals and animal infection.
During a stop in Malaysia and Indonesia, Yersin paid attention to the cultivation of rubber. In 1897, he began planting rubber in Suoi Dau and after eight years, in 1905, Michelin firm (France) received the first 1316kg of latex. He was interested in the method of planting, exploiting and processing rubber; he established an agricultural chemical laboratory. Here, the measures of extractive selection, scraping and coagulating latex of rubber, which was researched systematically, helped a lot of people who planted rubber in Indochina.
Time passed . . . Livestock and crop farms in Suoi Dau were expanded. Yersin took the position of Director of the two Pasteur Institutes in Saigon and Nha Trang
When he was on an India tour in 1897, Governor- general Paul Doumer witnessed the resort (sanatorium), which was organized well and saw soldiers stationed at the places from a height of 1000m to 2000m, with climate like in Europe did not contract tropical diseases. Doumer wanted to find one or more similar places for French officials and soldiers, who was tired, sick from the tropical climate, to avoid the heat firing body in the delta, enjoying the quiet moments in the cool air to recover their health. Doumer set out four necessary conditions for a resort: at least 1, 200 m in altitude, rich water resources, arable land and possibility to set up roads.
In 19th, July, 1897, Alexandre Yersin sent a message to Governor - general Paul Doumer to propose Lang Biang Plateau.
In March, 1899, Doumer sent a telegram to Dr. Yersin to inform that he was going to Phan Rang in the next 48 hours and climb with Yersin up the Lang Biang Plateau.
At that time, the big road from Nha Trang to Phan Rang was a path without a bridge crossing the river. Yersin immediately rode on horseback all day and night, only stopped at stations, which were from 15 to 20km away . On 25th March, 1899, Yersin came back to Nai (near Phan Rang) when the Kersaint ship got to the shore.
Doumer took a rest at the legation in Phan Rang, then he and the retinue rode horses immediately; that evening they intended to go to mountain, which was about 40km from Phan Rang.
Doumer’s horse gallopped. Thanks to a good horse, Yersin caught up with Mr. Doumer and came to Krongpha when the darkness fell.
Yersin put up a tent, took out two folding beds and some cans. Until midnight, the retinue and luggage just arrived.
Early next morning, the group began to climb up. The Pass road was bumpy and dangerous and everybody had to lead horses for walking. They arrived at Dran at 10 o'clock . On the plateau, where no Vietnamese lived. Dran had only one village of Thuong ethnic people, where population frequently suffered malaria. After bathing in the river and having a quick lunch, they continued their journey.
Before coming to Tram Hanh, the group led the horses on the pass road , but from Tram Hanh , the way was easier , so they continued to go on horse.
When Doumer, Langlois Captain and Yersin came nearer to the plateau, it was dark. All of them got close together, because of the dark they were unfamiliar with the terrain, and they could get lost. At 10 o’clock, they came to the troop station in present Dalat.
It's a simple cottage. Mr. Garnier – chief of station - was sleeping, he got up suddenly in the presence of strangers because no one had informed him before. At 1 pm, the retinue came. Nha Trang officer said with scared voice: “I heard the tiger roar, I realized it. ”
From early morning the group departed to Dang Kia. It’s cold, and on the way they saw many animals, which was called ca tong.
Over there, Doumer inspected the agricultural and meteorological station, presented the project to establish the future holiday resorts on the railway from Saigon, through the mountains to the Lang Biang Plateau and then coming to Quy Nhon.
Later, the project could not be carried out because when they studied and designed the engineers foresaw far more technical difficulties than setting up a coastal railway with a side branch railway from Phan Rang to Dalat.
In 1902, Yersin went to Hanoi to establish a medical college in Indochina and he was the first principal.
In 1914, World War I broke out. At that time, the Dutch had the exclusive right to manufacture quinine, the unique medicine to treat malaria. Yersin tried to seed quinquina in Suoi Dau and Dang Kia. He failed completely in Suoi Dau, but in Dang Kia it deserved his effort.
In 1917, Yersin crops quinquina in Hon Ba – the mountain near Suoi Dau. Initially they grew up well but later they died because the land was not suitable.
In July, 1923, the best quinquina in Hon Ba were planted in Dran and obtained good results. He continued to plant in small Lang Biang Plateau (Xuan Tho today) and Djiring.
In 1936, quinquina trees were planted on a large scale in Lan Tranh and Djiring, he harvested 30 tons of shells at a rate of quinine sulfate 7. 42%. In 1938, he collected 21 tons of shells with a higher rate of quinine sulfate (8. 5%).
In 1924, Yersin worked as a general inspector of the Pasteur Institutes in Indochina.
In 1933, he was a honorary president of the Pasteur Institute in Paris.
On 28 June, 1935, Yersin’s school was inaugurated in Da Lat, Yersin returned to Da Lat the last time before he died. On this occasion, to response to the statement of a student, he presented his impression when he stepped on Lang Biang Plateau:
"I was deeply touched by the affection you reserve for me. You are confident that I am really fond of you.
You gathered around me and made me become younger and reminiscent of ancient times. At that time, I was a young student, I often dreamt of a daring future that circumstances allow me to realize.
You made me relive the discovery of high-Lang Bian Plateau in June 1893 during a survey trip for the purpose of exploring Southern Central Vietnam, which was unknown at that time.
My impression was alive when I just went out of the forest, I stood on the edge of a vast, bare, bumpy plateau with three imposing Lang Bian Mounts. Undulating ground made me think of the sea agitating because of a giant wave as we often seen on the central coast at the starting of a storm.
The cool air made me forget about tiredness and I recall the joy of running up and down at a full speed on the green hills like a little schoolboy . . . "
While living in the Con neighborhood (Nha Trang), he was a kind neighbor, who often helped elders and fishing people, loved children. He was a model writer , he lived very simply, rich in benevolence, and the villagers called him an intimate name Nam(Five) .
In last years of life, Yersin was still absorbed in scientific research, orchids, astronomy, radio, leaving for humanity 55 scientific works. Some weeks before his death, although the disease was increasing, he continued to monitor tidal levels. . .
On 1, March, 1943, Yersin died peacefully, at the age of 80, leaving a deep grief. Thousands of Nha Trang people saw off his coffin to his final resting place at Suoi Dau, and his photo was worshiped at the Longquan and Linh Son temple in Khanh Hoa.