A boy on the steppe
Ilya Ilyich Mechnikov, known in France and to the world as Élie Metchnikoff, was born on May 15, 1845, in the village of Ivanovka near Kharkov, in the Russian Empire, now Kharkiv in Ukraine. He was the youngest of five children of Ilya Ivanovich Mechnikov, an officer of the Imperial Guard who owned land on the Ukrainian steppe, and Emilia Lvovna Nevakhovich. His mother came from a Jewish family: she was the daughter of the writer Leo Nevakhovich.
His father was often away, and it was his mother who shaped his education and encouraged his love of science. She steered him towards biology rather than medicine, judging him too sensitive to be a doctor. As a small boy he was passionately interested in natural history, especially botany and geology, and gave lectures on it to his younger brothers and the other children of the estate.
A young zoologist in a hurry
Metchnikoff studied natural sciences at the University of Kharkov and worked so hard that he completed the four-year course in two. He then studied in Germany and Italy, at Heligoland, Giessen, Göttingen, Munich and Naples. At Giessen in 1865 he discovered that a flatworm digests food inside its cells, an observation that would shape his greatest discovery. He received his doctorate in St. Petersburg in 1867 for work on the development of embryos of marine animals.
He taught at the new University of Odessa and in St. Petersburg, and in 1870 became professor of zoology and comparative anatomy at Odessa. His personal life in these years was marked by tragedy. His first wife, Ludmila Feodorovitch, was so ill with tuberculosis that she had to be carried to their wedding in a chair. For five years he did all he could to save her, but she died in 1873, and in his grief and poor health he tried to take his own life. In 1875 he married Olga Belokopytova, a student, who became his companion and helper for the rest of his life.
His early scientific reputation rested on embryology. With his friend Alexander Kovalevsky he compared how the embryos of very different animals develop, work that helped found the field of comparative embryology and earned the two men the Karl Ernst von Baer Prize in 1867. He published studies on the embryology of insects in 1866 and of jellyfish in 1886. This training in watching living cells under the microscope prepared him for the discovery that made his name.
Thorns in a starfish
In 1882, amid political turmoil after the assassination of Tsar Alexander II, Metchnikoff resigned from Odessa and set up a private laboratory in Messina, in Sicily. There he studied the transparent larvae of starfish, in which he could watch living cells moving about. He began to wonder whether these wandering cells might defend the animal against intruders.
To test the idea, he took small thorns from a tangerine tree that had been decorated as a Christmas tree for the children and pushed them into the larvae. The next morning he found the thorns surrounded by the mobile cells. He knew that in animals with blood vessels, white blood cells pour out of the vessels at sites of inflammation, and it struck him that they might be doing the same thing: gathering to engulf and digest bacteria that enter the body. The zoologist Carl Claus suggested the name phagocyte, from the Greek for devouring cell, and in 1883 Metchnikoff presented his theory in Odessa. The discovery transformed him, too: a man who had been deeply pessimistic set out with new purpose to prove his idea.
The battle over immunity
He gathered evidence across the animal world. In the tiny water flea Daphnia he watched phagocytes attack invading fungal spores. In mammals he found that weaker strains of the anthrax bacterium were devoured by phagocytes while the most virulent ones were not. In 1886 he became director of an institute in Odessa set up to give Louis Pasteur’s new rabies vaccine, but local hostility made his position impossible. In 1888 he went to Paris to ask Pasteur’s advice, and Pasteur gave him a laboratory at the new Pasteur Institute. He stayed there for the rest of his life, later becoming its deputy director.
His theory met fierce resistance. Many leading scientists, especially in Germany, believed the body fought infection mainly through substances dissolved in the blood, the humoral theory championed by Emil von Behring and others. For two decades Metchnikoff defended cellular immunity in papers and books, including a study of the comparative pathology of inflammation (1892) and Immunity in Infectious Diseases (1901). In the end both sides were right. In 1908 the Nobel Prize in Physiology or Medicine was shared between Metchnikoff, the champion of the cells, and Paul Ehrlich, who had shown how antibodies work, in recognition of their work on immunity.
In 1887 he also observed white blood cells being drawn towards bacteria, an early description of the way immune cells home in on sites of infection and inflammation.
How it changed medicine
Metchnikoff’s phagocytes are the front line of the body’s defence. Today they are known as neutrophils and macrophages, white blood cells that engulf bacteria, clear away dead cells and sound the alarm that calls up the rest of the immune system. He is honoured as the father of innate immunity and of the cellular theory of immunity, and his ideas about inflammation as a defensive response rather than simply a disease underpin modern understanding of wound healing, infection and many chronic illnesses.
Doctors use his insights every day: a white blood cell count is one of the most common tests in medicine, and patients whose phagocytes are destroyed by chemotherapy or missing because of inherited disorders are known to be at grave risk of infection. Research on how phagocytes recognise and swallow invaders continues to shape vaccines, treatments for sepsis and cancer immunotherapy.
Cholera, syphilis and the gut
Metchnikoff was a fearless experimenter, often on himself. During the cholera epidemic in France in 1892 he drank a culture of cholera bacteria and did not fall ill; of two volunteers who repeated the test, one was unaffected and the other nearly died. He concluded that other microbes in the gut might influence who gets sick. With Émile Roux he showed that syphilis could be transmitted to monkeys, opening the way to laboratory study of the disease, and they developed a calomel ointment to help prevent infection.
In later years he turned to ageing. He believed that toxins made by harmful gut bacteria contributed to old age and that lactic acid bacteria could crowd them out. Struck by reports of long-lived Bulgarian peasants who ate fermented milk, he promoted a diet of soured milk and drank it daily. In 1903 he coined the word gerontology for the scientific study of ageing. His specific theory of ageing has not survived, but he is widely regarded as the father of the idea of probiotics, and the science of the gut microbiome now studies questions he was among the first to ask. Earlier, in 1879, he had also found fungi that kill insects, and his student Isaak Krasilschik used one of them, the green muscardine fungus, against crop pests, an early step in biological pest control.
Jewish heritage
Metchnikoff’s Jewish ancestry came through his mother, whose family, the Nevakhoviches, was Jewish; her father, Leo Nevakhovich, was a writer. The Nobel Foundation’s biography notes simply that his mother was of Jewish origin. Metchnikoff was baptised in the Russian Orthodox Church and later became an atheist.
He is often counted, with his fellow laureate Paul Ehrlich, among the first Jewish recipients of the Nobel Prize in medicine. His career also reflects the experience of many scientists of Jewish descent in the Russian Empire, who found greater freedom to work in western Europe; it was the reactionary turn in Russia after 1881 that first drove him from his post in Odessa.
The man
At the Pasteur Institute he became a legendary figure, with long hair and an unkempt beard. The Nobel Foundation’s biography records that he wore overshoes in all weathers, carried an umbrella, had pockets stuffed with scientific papers, always wore the same hat and, when excited, often sat on it.
He wrote widely for the general public on science, death and the meaning of life, notably in The Nature of Man (1903) and The Prolongation of Life (1907), arguing that science could reduce disease and suffering and allow people to meet death calmly at the end of a full life.
Last years and legacy
From 1913 Metchnikoff suffered a series of heart attacks, and the outbreak of the First World War distressed him deeply. He died of heart failure in Paris on July 15, 1916, aged 71, at the Pasteur Institute, in the rooms where Pasteur had spent his final days. At his wish his body was used for medical research and then cremated, and his urn rests in the library of the Pasteur Institute.
Universities and research institutes in Odesa, Kharkiv and St. Petersburg bear his name. More than a century after a zoologist pushed a tangerine thorn into a starfish larva, every account of how the body fights infection begins with the cells he discovered.
His honours included the Copley Medal of the Royal Society in 1906, an honorary doctorate from the University of Cambridge, honorary membership of the academies of medicine in Paris and of sciences and medicine in St. Petersburg, and, in the year of his death, the Albert Medal of the Royal Society of Arts.
Sources & further reading
Ilya Mechnikov, Biographical, NobelPrize.org · Ilya Ilyich Mechnikov (Élie Metchnikoff) (1845–1916), The Embryo Project Encyclopedia, Arizona State University · Elie Metchnikoff, Jewish Virtual Library · Élie Metchnikoff, Wikipedia · Jewish Nobel Prize Winners in Physiology or Medicine, JINFO.org · Researched from the sources above and checked against them. Spotted an error? Tell us.
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