Bacteriophages Arriving in India, Hankin worked on the frequent outbreaks of
cholera, challenging the prevalent view that "
miasmas" were responsible for them. He demonstrated to the public and the officials that
micro-organisms were the cause and published his notes and opinions translated into Indian languages. In 1896 he published, through the
Pasteur Institute, "''L'action bactericide des eaux de la Jumna et du Gange sur le
vibrion du cholera''", a paper in which he described the antibacterial activity of a then unknown source in the
Ganges and
Jumna rivers in India. He noted that "It is seen that the unboiled water of the Ganges kills the cholera germ in less than 3 hours. The same water, when boiled, does not have the same effect. On the other hand, well water is a good medium for this microbe, whether boiled or filtered." He suggested that it was responsible for limiting the spread of
cholera. While many observers have considered this as evidence of early observations of
bacteriophage activity, some of his later experiments raise doubts. Hankin subsequently suggested that the bactericidal action was through a "volatile" agent. He further conducted experiments where he showed that Ganges water heated in hermetically sealed containers retained their ability to kill bacterial cultures while open one on heating lost their potency. A 2011 commentator adds that Hankin's initial results suggest extremely high phage counts which seem improbable. It was however not until twenty years later that phage activity was demonstrated without doubt by the experiments of
Félix d'Herelle later described at the Pasteur Institute. This observation on the water of the
Ganges became quite famous, and even found mention in
Mark Twain's
More Tramps Abroad. Hankin was responsible through his letters to officials in prompting the establishment of the
Pasteur Institute of India at
Kasauli in 1904. One of Hankin's duties as a chemical examiner was to attend to court cases that required the analysis of scientific forensic evidence. He notes that about 700 to 1000 cases of supposed poisoning required tests for poisons to be conducted.
Researches in Agra and Bombay Hankin studied
immune responses with experiments where he injected rabbits with tetanus to induce immunity in them. He took their serum and injected them in rats to demonstrate how the immunity could be transferred. Hankin started the practice of using
potassium permanganate in wells as a means for controlling cholera. His theory was that the germs needed organic matter to survive and that permanganate would oxidize it and make it unavailable. In 1895 the press noted that Hankin had been overzealous with his experimentation and had infected himself with cholera by drinking water that he thought had been treated using
potassium permanganate. The efficacy of this method of disinfecting wells was however questioned in later studies. The editors of the journal
Science Progress lamented that Hankin had been largely unrecognized for his contributions to human health and hygiene: "Hankin's work has been of greater importance to India than the work or no-work of many persons who have received more honours and acknowledgements. Really, in some respects the British remain barbarians to the present day, and he should write an article on the mental ability of the Indian Powers-that-Be !" When he retired in 1922, he was awarded a
Kaisar-i-Hind Medal of the first class. Hankin contracted a mild case of bubonic plague and recovered. During this period he took some interest in
vultures at the
Towers of Silence, which had apparently increased in numbers. and "On the Epidemiology of Plague" in the
Journal of Hygiene in 1905. His interests also drifted towards the subject of flight, possibly through his observations on vultures. In 1914 he published
Animal Flight about
soaring flight in birds, based on observations he made, particularly of gulls and vultures, in
Agra. He introduced a technique to plot the flight path of soaring birds by tracing their movements on a horizontal mirror. He identified thermals and currents as a requirement for soaring and dynamic soaring. His work on soaring birds caught the interest of Cambridge mathematician turned meteorologist
Gilbert Walker who was also at Simla who discussed the role and nature of thermals and eddies in providing birds with the lift needed. With
D. M. S. Watson, at the time a lecturer in vertebrate palaeontology at University College London, he also published a pioneering paper on the flight of
pterodactyls in the
Aeronautical Journal (1914). He also studied butterflies and their flight. He noted the brightness of patterning on the underside of
Papilio demoleus and considered if it was a warning for aerial predators.
Other areas of work , studied by Hankin During the thirty years that he spent in India, Hankin took interest not just in tropical diseases but also the effects of
opium and the action of cobra
venom, working sometimes in collaboration with
Albert Calmette and
Waldemar Haffkine. Outside of his health related research he took an interest in such diverse topics as the fauna inhabiting the dome of the
Taj Mahal, insect
camouflage and its military application, native folklore and art. While in India, Hankin studied the
Islamic geometric patterns that he observed, publishing some of them in 1905. His main findings only found publication from 1925, after his return to the UK, when "The Drawing of Geometric Patterns in Saracenic Art" finally appeared in
Memoirs of the Archaeological Survey of India, under the editorship of
J. F. Blakiston. This and later writings have influenced computer scientists and mathematicians in the 21st century, notably Craig S. Kaplan. ==Return to England==