Manson, Patrick, 1844–1922, English parasitologist. After receiving his medical degree (1866) from the university at Aberdeen, Scotland, Manson left for China where he was to spend 24 years, studying such diseases as tinea, Calabar swelling, and blackwater fever. In 1878 he observed that filariae, the worms that cause elephantiasis in man, pass part of their life cycle in the Culex mosquito; he thus led the way in the study of the transmission of diseases caused by parasites. In 1894 he made the deduction that the parasite of malaria passes part of its life cycle in the mosquito, a theory that Ronald Ross was to verify three years later. A founder of two schools devoted to the study of tropical diseases, one at Hong Kong (1886) and the other at London (1898), Manson is often described as the father of tropical medicine.