A pioneering Scottish physician who worked in China where he discovered the developmental phase of filaria worms and set up a school of medicine that developed into the University and Medical School of Hong Kong. Returning to London, he became physician to the Seamen's Hospital in 1892. He played a central role in the development of tropical medicine as a distinct discipline, publishing on tropical diseases, being instrumental in the setting up of the London School of Tropical Medicine in 1899, and becoming physician and advisor to the Colonial Office in 1897. He propounded the theory that malaria was propagated by mosquitoes. He was elected Fellow of the Royal Society in 1900 and awarded CMG in 1900, KCMG in 1903, and GCMG in 1912. The plaque was used as the obverse design for the Royal Society of Tropical Medicine and Hygiene prize medal first awarded in 1923.