Theobald Smith

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Theobald Smith
Theobald Smith 2.jpg
Born(1859-07-31)July 31, 1859
DiedDecember 10, 1934(1934-12-10) (aged 75)
Alma materCornell University, Albany Medical College
Known forTexas cattle fever, Salmonella
AwardsManson Medal (1932)
Copley Medal (1933)
Scientific career
InstitutionsUS Department of Agriculture, Harvard University, Rockefeller University

Prof Theobald Smith FRS(For)[1] HFRSE (July 31, 1859 – December 10, 1934) was a pioneering epidemiologist, bacteriologist, pathologist and professor. He is widely considered to be America's first internationally significant medical research scientist.[2][3] His work included the study of Texas cattle fever and the epidemiology of cattle infected by ticks transmitting protozoa. He also discovered a species of Salmonella, named for his chief Daniel E. Salmon, and studied anaphylaxis, then referred to as Theobald Smith phenomenon.[4] He is also known for the "law of declining virulence", in which host and pathogen develop a "mutually benign relationship" over time.[5][6] Smith taught at Columbian University (now George Washington University) and established the school's department of bacteriology, the first at a medical school in the United States.[4] He also worked at Harvard University and the Rockefeller Institute.


Smith was born in Albany, New York, the son of Philip Smith and his wife, Theresa Kexel.[7]

He received a Bachelor of Philosophy degree from Cornell University in 1881, followed by an MD from Albany Medical College in 1883.[2] After his graduation from medical school, Smith held a variety of temporary positions which might broadly be considered under the modern heading of "medical laboratory technician". After some prodding by his former professors, Smith secured a new research lab assistant position with the Veterinary Division of the US Department of Agriculture (USDA) in Washington, D.C., beginning his position there in December 1883.[8]


Smith became the Inspector of the newly created Bureau of Animal Industry (BAI) in 1884. Established by Congress to combat a wide range of animal diseases—from infectious disease of swine to bovine pneumonia, Texas cattle fever to glanders—Smith worked under Daniel E. Salmon, a veterinarian and Chief of the BAI.[9] Smith also discovered the bacterial species which would eventually form the genus Salmonella. After two years of work studying the efficacy of bacterial vaccination in pigs, Smith erroneously believed he had found the causative agent of hog cholera.[10]

Smith turned his attention to Texas fever, a debilitating cattle disease; this work is detailed in a chapter in Microbe Hunters, by Paul De Kruif. In 1889, he along with the veterinarian F.L. Kilbourne discovered Babesia bigemina, the tick-borne protozoan parasite responsible for Texas fever. This marked the first time that an arthropod had been definitively linked with the transmission of an infectious disease and presaged the eventual discovery of insects as important vectors in a number of diseases (see yellow fever, malaria).

Smith also taught at Columbian University in Washington, D.C. (now George Washington University) from 1886 to 1895, establishing the school's Department of Bacteriology. In 1887, Smith began research on water sanitation in his spare time, investigating the level of fecal coliform contamination in the Potomac River. Over the next five years, Smith expanded his studies to include the Hudson River and its tributaries.[11]

While Smith's work at the BAI had been highly productive, he chafed against the federal government bureaucracy and the lack of leadership from his supervisor. In 1895 Smith moved to Cambridge, Massachusetts to accept a dual appointment: serve as professor of comparative pathology at Harvard University, and direct the pathology lab at the Massachusetts State Board of Health.[8]

Smith joined the Rockefeller Institute for Medical Research as Director of the Department of Animal Pathology in 1915 and remained there until his retirement in 1929.

In 1933, Smith was awarded the Royal Society's prestigious Copley Medal "For his original research and observation on diseases of animals and man.".


  • Parasitism and Disease (1934)

Other discoveries

  • Observed differences between human and bovine tuberculosis (1895).
  • Discussed the possibility of mosquitos as a malaria transmission vector (1899).
  • Variation and bacterial pathogenesis (1900).
  • Discovered anaphylaxis (1903), which is also sometimes referred to as "Theobald Smith's phenomenon".[12]
  • Brucellosis infections
  • Used toxin/antitoxin as a vaccine for diphtheria (1909).
  • In the process of investigating an epidemic of infectious abortions of cattle in 1919, Smith described the bacteria responsible for fetal membrane disease in cows now known as Campylobacter fetus.[13]


  1. ^ Nuttall, G. H. F. (1935). "Theobald Smith. 1859-1934". Obituary Notices of Fellows of the Royal Society. 1 (4): 514–521. Bibcode:1935SciMo..40..196W. doi:10.1098/rsbm.1935.0014. JSTOR 768981.
  2. ^ a b Dolman, C.E.; Wolfe, R.J. (2003). Suppressing the Diseases of Animals and Man: Theobald Smith, Microbiologist. Boston Medical Library. ISBN 0-674-01220-8.
  3. ^ Middleton, James (July 1914). "A Great American Scientist: Dr. Theobald Smith, Head of The New Department Of Animal Diseases At The Rockefeller Institute". The World's Work: A History of Our Time. Doubleday, Page & Co. XLIV (2): 299–302. Retrieved 2009-08-04.
  4. ^ a b "1869 - 1930 - Cornell DU Alumni". Retrieved 2018-04-18.
  5. ^ Fall, Ed; Yates, Christian (1 February 2021). "Will coronavirus really evolve to become less deadly?". The Conversation. Retrieved 29 November 2021.
  6. ^ Orent, Wendy (16 November 2020). "Will the Coronavirus Evolve to Be Less Deadly? - History and science suggest many possible pathways for pandemics, but questions remain about how this one will end". Smithsonian Magazine. Retrieved 29 November 2020.
  7. ^ Biographical Index of Former Fellows of the Royal Society of Edinburgh 1783–2002 (PDF). The Royal Society of Edinburgh. July 2006. ISBN 0-902-198-84-X.
  8. ^ a b Kruif, Paul De (2002) [1926]. Microbe Hunters. Harvest Books. ISBN 0-15-602777-1.
  9. ^ J.H., Brown (1 July 1935). "Theobald Smith 1859-1934". J Bacteriol. 30 (1): 196. Bibcode:1935SciMo..40..196W. doi:10.1128/JB.30.1.1-3.1935. PMC 543631. PMID 16559815.
  10. ^ "Theobald Smith, 1859-1934: A Fiftieth Anniversary Tribute" (PDF). ASM News. 50: 577–80. 1984. Archived from the original (PDF) on 2004-09-07.
  11. ^ T., Smith (1893). "A new method for determining quantitatively the pollution of water by fecal bacteria". 13th Annual Report of the State Board of Health of New York for 1892: 712–22.
  12. ^ "Whonamedit - dictionary of medical eponyms". Retrieved 2018-04-18.
  13. ^ Smith, T.; Taylor, M.S. (1919). "Some morphological and biological characters of the Spirilla (Vibrio fetus, n. sp.) associated with the disease of the fetal membranes in cattle". J Exp Med. 30 (4): 299–311. doi:10.1084/jem.30.4.299. PMC 2126685. PMID 19868360.

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