(b. Woolwich, England, 5 June 1854; d. Washington, D. C., 16 September 1907),
Carroll was the son of James and Harriet Chiverton Carroll. He attended Albion House Academy, Woolwich, in preparation for an engineering career in the navy. At the age of fifteen, however, he imigrated to Canada and in 1874, at the age of twenty, he enlisted in the U. S. army. He remained in the army until his death. In 1883 Carroll became a hospital steward, a position he held officially until 1898, when, during the Spanish-American War, he was appointed acting assistant surgeon. In 1886–1887 he attended medical school at the University of the City of New York (now New York University), and in 1889 he continued at the University of Maryland, from which he received the M. D. in 1891.
From 1891 to 1893 Carroll attended the new postgraduate classes in bacteriology and pathology at Johns Hopkins University, coming into contact with several brilliant Americans who later became famous in medicine. In 1893, at the Army Medical School in Washington, Carroll met Walter Reed and in 1895 was assigned to assist Reed, then curator of the Army Medical Museum. While stationed in Washington, Carroll taught at Columbian (now George Washington) University. After Reed’s death in 1902, Carroll succeeded him at the Army Medical Museum and at George Washington, reaching the full professorship of pathology and bacteriology in 1905.
In 1899 Reed and Carroll disproved Sanarelli’s theory that Bacillus icteroides is the specific agent in yellow fever. In 1900 Carroll was made second in command to Reed of the now-famous commission sent to Cuba to study yellow fever. Reed planned a series of experiments to determine how the disease is spread and what causes it. Since Reed had to be in Washington a large part of the time, Carroll was responsible for much of the actual work carried out. On 27 August 1900 Carroll, who did not put much stock in the theory of Carlos Finlay that a mosquito acts as the vector in yellow fever, caused an infected mosquito to bite his arm. Four days later he came down with the first experimental case of yellow fever. He nearly died then, and he acquired a heart disease from which he did die a few years later, one of the genuine martyrs of science. Much bitterness was engendered because Congress refused adequate compensation to his wife, Jennie M. George Lucas Carroll, and their seven children. Before his death Carroll did receive promotions to the rank of major, and the universities of Maryland and Nebraska awarded him honorary degrees.
Carroll’s most important published contributions to science consist of works written jointly with Walter Reed and others defining the method of the propagation of yellow fever, based upon experiments that were executed largely by Carroll, and a series of papers on the etiological agent in that disease. His most important personal contribution was the demonstration, at Reed’s suggestion, that the bacteriological agent of yellow fever is a filterable virus. Prior to that time, ultramicroscopic phenomena had been identified clearly as pathogens only in tobacco mosaic disease and cattle foot-and-mouth disease. Carroll’s report was among the first to establish a virus etiology of a human disease.
A list of Carroll’s publications is in John C. Hemmeter, Master Minds in Medicine (New York, 1927), pp. 319–320. This list should be supplemented by standard indexes of the day.
For biographical material, see James M. Phalen’s article in the Dictionary of American Biography, III,525–526; the article by Caroline W. Latimer in Howard Atwood Kelly and Walter Lincoln Burrage, eds., American Medical Biography (New York, 1920); and Hemmeter, op. cit, pp. 297–336, which contains documents and letters as well as some interview material. Good obituaries include that in Bulletin of the Johns Hopkins Hospital, 19 (1908), 1–12; and Howard A. Kelly, in Proceedings of the Washington Academy of Sciences, 10 (1908), 204–207.
John C. Burnham