Carlos Finlay's Google doodle on December 3. Photograph: Google Google's latest doodle celebrates the birthday of Carlos Finlay, the Cuban physician and scientist who theorised that yellow fever was spread by mosquitoes. Of French and Scottish descent, Finlay was born in 1833 in Puerto Príncipe, now the Cuban city of Camagüey, and studied at Jefferson medical college in Philadelphia, Pennsylvania. He finished his studies in Havana and Paris before settling in Cuba to open a medical practice. Finlay was appointed by the Cuban government in 1879 to work with a North American commission studying the causes of yellow fever, and two years later was sent as the Cuban delegate to the fifth International Sanitary Conference in Washington DC. At the conference, he urged the study of yellow fever vectors and later stated that the carrier was the mosquito Culex fasciatus, now known as Aedes aegypti.