The German Doctor Who Caught Cholera in a Bottle

The German Imperial Cholera Commission landed at Alexandria, Egypt, on 24 August 1883. There were five members; the senior member was Robert Koch, the 39-year-old director of the Imperial Health Office in Berlin, already famous in Europe for having identified the tuberculosis bacterium the previous year. The Commission’s task was to determine, by the methods of the new science of bacteriology, what caused cholera. The 1883–84 cholera pandemic, the fifth global cholera pandemic of the 19th century, had reached Egypt in late July and was killing hundreds of people a day in Alexandria.

Koch was at the corpse on the morning of his arrival. By the end of the first week he had cultured, from material taken from the intestinal mucosa of cholera victims, a single distinctive comma-shaped bacterium that was present in every fatal case and in no non-cholera case. By mid-September the Egyptian epidemic was burning out. The Commission left Alexandria for Calcutta in late October to confirm the finding in the disease’s endemic home. In Calcutta, between November 1883 and February 1884, Koch demonstrated that the same comma-shaped organism — Vibrio cholerae — was present in every cholera case, was absent in non-cholera diarrheal disease, and was specifically present in the water of the contaminated tanks that surrounded the city.

He reported his findings to the German government in February 1884 and to the London medical community in his BMJ address of August 1884. He was 40 years old. The traditional medical position that cholera was caused by miasmatic atmospheric corruption was, after thirty years of accumulating contrary evidence going back to John Snow and Henry Whitehead, finally indefensible.

The Wollstein years

Robert Heinrich Hermann Koch was born on 11 December 1843 in Clausthal, a small mining town in the Harz mountains of central Germany. He was the third of thirteen children. His father was a mining engineer. He studied medicine at Göttingen, served as an army surgeon in the Franco-Prussian War of 1870–71, and was then appointed district physician (Kreisphysikus) at Wollstein, a small town in what was then the eastern Prussian province of Posen (modern Wolsztyn, Poland).

Wollstein had a population of approximately 4,000 and was a long way from any university or research institution. Koch was the only doctor for a sizable rural district; he traveled extensively to see patients on horseback; and in the room behind his consulting office, on his own time and his own money, he assembled what was almost certainly the most sophisticated bacteriological laboratory then in private use anywhere in Europe. His wife Emmy gave him a microscope for his 28th birthday in 1871. He used it for the next forty years.

The work that established Koch’s international reputation was done at Wollstein between 1872 and 1880. He demonstrated, against the prevailing medical orthodoxy, that the bacterium Bacillus anthracis was both the necessary and sufficient cause of anthrax in livestock, that the disease could be transmitted by injecting purified bacterial cultures into healthy animals, and that the bacterium produced long-lived spores in soil. The work was published in 1876 and gave the first complete demonstration that a specific microorganism could cause a specific infectious disease. It was the foundation of all subsequent medical bacteriology.

The Imperial Health Office at Berlin recruited Koch in 1880. He moved his family, his microscopes, and his laboratory to the capital. Over the following three years he and his small staff identified the bacterial causes of tuberculosis (1882), confirmed by the methodological standard now known as Koch’s postulates: the bacterium must be present in every case of the disease; it must be isolatable in pure culture from a diseased host; the cultured organism must cause the disease when injected into a healthy host; and the bacterium must be recoverable from the experimentally infected host.

The Egyptian commission

The 1883 cholera pandemic, the fifth of the 19th century, was emerging westward out of India in early 1883. By summer it had reached Egypt via the Mecca pilgrimage and Indian Ocean shipping. The German government convened the Egyptian Cholera Commission on 16 August 1883 and named Koch its leader. The French Pasteur Institute simultaneously dispatched a competing commission led by Pierre-Émile Roux. The two teams arrived at Alexandria within days of each other. They were openly hostile, the result of post-Franco-Prussian War scientific competition.

The German Commission worked out of the Egyptian Government Hospital at Alexandria. Koch conducted autopsies on cholera victims, took samples from the intestinal contents of the dead, and cultured the samples on his preferred medium — gelatin plates streaked with cholera material and incubated at body temperature. The comma-shaped bacterium grew out within 24 hours from every cholera case. He had not seen the organism elsewhere. He photographed it through his microscope. He demonstrated it to the rest of the Commission and to visiting Egyptian physicians.

There was one major prior claim. The Italian anatomist Filippo Pacini had described a comma-shaped bacterium in cholera victims at Florence in 1854 and had correctly identified it as the disease’s cause. Pacini’s work, published in Italian in a regional medical journal, had been ignored by the larger European medical community for thirty years. Koch was aware of Pacini’s work by 1884 and acknowledged it. The international convention of naming priority was retroactively corrected by the International Committee on Bacteriological Nomenclature in 1965, which formally renamed the bacterium Vibrio cholerae Pacini 1854. The discovery is now usually credited to Pacini in 1854 and to Koch in 1883 simultaneously, with Koch’s later work providing the definitive demonstration.

By early September 1883 the French Commission had failed to identify the cholera bacillus and had suffered the death of its second-in-command, Louis Thuillier, from a fulminant case of the disease. Thuillier was twenty-seven. Koch attended Thuillier’s funeral in Alexandria and acted as one of the pallbearers. The gesture was reported in the European press and produced a temporary reduction in the Franco-German scientific hostility.

Calcutta

The Egyptian epidemic burned out in early October. The Cholera Commission, with the bacterium identified but not definitively confirmed, sailed for Calcutta in late October 1883 to study the disease in its endemic Bengali home. They arrived on 11 November.

Koch spent the following three and a half months in Calcutta. He examined approximately fifty cholera cases, cultured the bacterium from every one, and demonstrated its presence in the water of the contaminated rainwater tanks (tanks) that supplied much of the city. The tanks were the Bengali functional equivalent of the Broad Street pump in 1854 Soho: standing water in which the bacterium could persist and into which the diarrheal output of cholera victims was being directly washed by residents using the tanks for laundry and washing of cooking vessels. Koch was able to map the relationship between specific tanks and specific cholera cases in a way that paralleled John Snow’s London map of three decades earlier.

The Indian work confirmed the Egyptian work. The bacterium was now indisputably the cause of cholera. The Commission left Calcutta in March 1884 and returned to Berlin via the Suez Canal.

After

The German government formally celebrated Koch’s return at a state reception in Berlin in May 1884. He was promoted to full Professor of Hygiene at the Berlin University. He was knighted as a Privy Councillor in 1890. He won the Nobel Prize in Physiology or Medicine in 1905 — for tuberculosis rather than cholera, but the cholera work was prominently cited in the award.

The medical legacy of the 1883–84 cholera work was the practical confirmation of the germ theory of infectious disease. The traditional miasmatic theory, defended in Germany most stubbornly by the Munich hygienist Max von Pettenkofer, finally collapsed; Pettenkofer himself, in 1892, drank a flask of pure cultured cholera bacterium prepared by Koch to demonstrate that it could not cause the disease, suffered a non-fatal but unpleasant week of severe diarrhea, and continued to insist for the rest of his life that the cholera bacterium was a necessary but not sufficient cause. He killed himself in 1901.

Koch’s later career included substantial work on tuberculosis (the failed therapeutic tuberculin, 1890; the BCG vaccine descended distantly from his lines of work), African sleeping sickness, rinderpest, and bubonic plague. He died of a heart attack at the spa town of Baden-Baden on 27 May 1910, aged 66. The original microscope his wife had given him in 1871 is preserved in the Robert Koch Institute in Berlin.

The cholera that the Commission had identified in 1883 has not been eradicated. Vibrio cholerae continues to cause approximately 1.3 million to 4 million cases of cholera per year worldwide and approximately 20,000 to 140,000 deaths, almost all in regions with inadequate access to clean water. The disease that John Snow walked through Soho to map in 1854, that Koch traced to its bacterial cause in Alexandria and Calcutta in 1883, and that remains an active public-health problem in 2025, is the same disease. The bacterium has not changed in any substantial way.