Carlos Juan Finlay was a Cuban physician and biologist, who, in 1881, suggested that yellow fever, an acute febrile illness fatal to half its victims, was transmitted by mosquitoes. His theory, confirmed in 1900 by the American surgeon Walter Reed, led to widescale control of the disease. Finlay also made important contributions toward the understanding of infant tetanus and of cholera.

Carlos Juan Finlay was born in Camagüey, Cuba, on December 3, 1833. He was one of seven children born to Edward Finlay, a Scottish physician who had fought alongside Simon Bolivar, and Eliza Isabel, née deBarrés, a French woman. The family owned a large coffee plantation in Guanimar, in the Alquizar region of Cuba. Finlay spent his early childhood on this plantation and in a family home in Havana. He received his schooling from his paternal aunt, Ana, who had started a school in Edinburgh...