Carlos Juan Finlay

Date: c. 1900
Owner: Wikimedia
Source Type: Images


Cuban physician and epidemiologist Carlos Juan Finlay (1833-1915) discovered that yellow fever was transmitted by mosquitoes and that mosquitoes could also be used to inoculate people against the disease. He presented this theory in 1881 at the International Sanitary Conference in Washington, D.C., yet few scientists or physicians believed him. From 1881 to 1900, Finlay conducted 102 inoculations on volunteers and considered the results as proof of his theories. Although the experiments gave him more credence, many physicians thought that his volunteers were exposed to too many different variables, thus skewing Finlay's results. His hypothesis was not generally accepted until 1900, when Dr. Walter Reed carried out a series of controlled experiments at Camp Lazear to determine whether yellow fever was transmitted by contact, as many believed, or by mosquitoes.

It is interesting to note that despite Finlay's incredible scientific achievements, his motivation was not altogether altruistic by modern standards. In the late nineteenth-century, Cuba encouraged white immigration, partially because they thought it would help to modernize the country and partially due to traditional fears that blacks and mestizos would assume too much clout in Cuban society. Yellow fever, however, was most devastating to new immigrants and the high mortality rates deterred many whites who may otherwise have moved to the island. Finlay's focus on yellow fever was thus catalyzed by social influences that, like many such measures in late nineteenth-century Latin America, were concerned with issues of race.


Stepan, Nancy. "The Interplay Between Socioeconomic Factors and Medical Science: Yellow Fever in Cuba and the United States." Social Studies of Science. 8 (1978): 297-424.

CITATION: Carlos Juan Finlay, Cuban Physician. Courtesy of WikiMedia Commons,