Henry Bayon, Doctor of Medicine (MD), held an appointment as Craggs Investigator at the London School of Tropical Medicine in 1911. There he investigated the cause and nature of leprosy. Among others he published "Demonstration of specimens relating to the culture of the leprosy bacillus" (1911) and "Organisms cultivated from the lesions of human leprosy" (1912) in The British Medical Journal, "The culture and identification of the germ of leprosy and the relationship of the human disease to rat leprosy" (Transactions of the Royal Society of Tropical Medicine and Hygiene, 1912), and "The leprosy problem in the British Empire" (The Lancet, 1913).
In April 1912 Bayon was appointed as bacteriologist for leprosy research in the Department of the Interior of the Union of South Africa. He was probably stationed on Robben Island for some time, as he appears on a staff photo taken on the island in 1913, including staff of the leper colony, mental hospital and others. His investigations and recommendations were written up in the following Parliamentary Report: South Africa, Department of the Interior. Report by the Government Research Bacteriologist (leprosy) on the necessity or advisability of segregation in relation to the conditions and spread of leprosy in South Africa at the present time; the measures to be provided for the prevention and cure of leprosy; and the suitability of Robben Island as a place of detention for lepers (Cape Town, 1913, 9 pp). On 7 March 1913 he attended a meeting of the Durban Medical Society and presented a well-received lecture on leprosy. Later he published a paper on a harmless group of parasites found in arthropods, "Herpetomonidae found in Scatophaga hottentota and Chamaeleon pumulus" in the Transactions of the Royal Society of South Africa (1915-1916, Vol. 5, pp. 61-65), though he had probably left the country by then.
Other publications by Bayon included the following: "The cultivation of Trypanosoma rhodesiense, Stephens and Fantham" (Royal Society of London Proceedings, Series B, 1912), "A new species of Treponema found in the genital sores of rabbits" (British Medical Journal, 1913), and "Racial and sexual differences in the appendix vermiformis" (The Anatomical Record, 1920). He was still active in 1932, for in that year he contributed an abstract to "Abstracts of current literature" in the journal Radiology.