Watson, Sir Malcom (1873–1955), British physician. In 1900 Watson entered the medical service in Malaya, the site of frequent epidemics of malaria. He quickly embarked upon a vigorous program of mosquito control. Malaria and its prevention were to become his lifelong interests. In 1928 he left Malaya to serve at the Ross Institute of Tropical Hygiene in London. He later served as the director of the Institute and of the branches he established in India and West Africa.