India, was the jewel in Britain’s proverbial colonial crown and among the scientists sent out to India was Ernest Hankin, who arrived at the port of Bombay in 1891, a bacteriologist by training who had matriculated from St John’s College, Cambridge, in 1886, and had interned in the labs of eminent scientists like Frank Wesbrook in London, Robert Koch in Berlin and Louis Pasteur in Paris, before taking up his assignment in India. Hankin was appointed chemical examiner, government analyst and bacteriologist for the United Provinces, Punjab and the Central Provinces, and posted in Agra. His main task was to protect British troops from infectious diseases, especially the dreaded cholera. Cholera is caused by a sausage-shaped bacterium transmitted to humans through contaminated water or food and triggers violent diarrhoea characterised by ‘rice-water stools’. If left untreated, cholera can be lethal. Much of Hankin’s work entailed collecting water samples all year round so that he could monitor outbreaks of cholera in towns and villages. He was a keen swimmer and a skilled boatman and enjoyed taking boat rides along the Jamuna and Ganga when he went out on these inspections.

In February 1894, Hankin was on one such quest. He was on the lookout for the first signs of a cholera outbreak at the Maagh Mela in Allahabad, a fortnight-long Hindu festival that attracted over 3 million pilgrims every day. During the festival, devotees took a holy dip at the confluence of the mighty Ganga and Jamuna rivers, and remained on the riverbanks for days. Hankin collected and analysed water samples and what he found confirmed a pattern that he had noticed since he first began inspections of these rivers—there was very little bacterial contamination in their waters despite the multitudes of people and their cattle bathing in them, discarding their waste and burning corpses along their banks. In an 1895 paper, Hankin wrote that the Ganga was cleaner than most British or European rivers despite the way they were treated. Hankin wondered how and why this Indian rivers was able to avoid that kind of decay.