John was educated at Clifton College; at University College, London; and at St Mary’s Hospital. He started with the intention of being a scientific chemist, and after leaving Clifton went to Germany. Subsequently he entered at University College, London where he was Tufnell scholar in 1885. Two years later he graduated as B.Sc. and in 1890 was appointed assistant lecturer on physics and demonstrator of chemistry in St Mary’s Hospital Medical School. After holding those appointments for three years he commenced his medical studies at St Mary’s where he had a successful career, graduating M.B. in 1896 and D.P.H. in the following year. After qualifying he was appointed on plague duty in India, where he worked in collaboration with Professor Haffkine. Subsequently he served throughout the South African War and was for the greater part attached to No 8 General Hospital at Bloemfontein. On his return from South Africa he was for a time assistant medical superintendent of Paddington Infirmary, after which he settled in practice at Southsea and was shortly afterwards appointed honorary assistant physician to the Royal Portsmouth and Gosport Hospital. When war was declared, John was mobilised as Captain in the R.A.M.C., T.F. and was appointed sanitary specialist officer for Portsmouth. His duties involved the inspection of the sanitation of the various camps in Hampshire, and the carrying out of the bacteriologic work in connection with the various epidemics that arose. He worked assiduously at these posts, but it was claimed that he had been thoroughly overworked, and was therefore susceptible to infection. On 20th March 1916, John began to display symptoms of cerebro-spinal meningitis, a disease which he had contracted from a military patient under his care. He died ten days later.