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Cholera Epidemics in the 19th Century

The Great Plague of London, 1665

The Boston Smallpox Epidemic, 1721

“Pestilence” and the Printed Books of the Late 15th Century

Spanish Influenza in North America, 1918–1919

Syphilis, 1494–1923

Tropical Diseases and the Construction of the Panama Canal, 1904–1914

Tuberculosis in Europe and North America, 1800–1922

The Yellow Fever Epidemic in Philadelphia, 1793

General Materials

Notable People

Related Links


Concepts of Contagion and Epidemics

Fighting the Pneumonic Plague in Manchuria, illustration in, Under the Red Cross Flag at Home and Abroad, Philadelphia: J. B. Lippincott Co., 1915. From the holdings of Harry Elkins Widener Memorial Library—Harvard College Library
Fighting the Pneumonic Plague in Manchuria, Under the Red Cross Flag at Home and Abroad. From the holdings of Harry Elkins Widener Memorial Library—Harvard College Library.

The concept of “contagion,” together with the concept of “contagiousness,” is thousands of years old. The meanings of both the word and the concept have changed over time. Two of the oldest diseases associated with contagiousness are leprosy, which is mentioned in the Hebrew Bible, and smallpox. Historically, both the plague and syphilis were believed to be contagious.

Before the late 19th century, many diseases that we now know to be contagious (such as cholera and tuberculosis) were considered non-contagious by educated physicians. In fact, in many cases, a belief in contagiousness was associated with folk traditions and unsophisticated laypeople.

The Causes of Contagion: An Historical View

Modern germ theory, developed between 1870 and 1900, associates most diseases with specific entities. But earlier systems of medicine held the belief that one disease could change into another or might manifest itself differently in different people.

Diseases—both individual and epidemic—did not result from action on the human body by a disease-causing agent, but, instead, were the results of individual susceptibilities and individual interactions with the environment. In turn, these considerations were often affected by the education, moral values, class, and politics of physicians and the societies in which they lived.

Explaining Disease Transmission Before the Germ Theory

It has always been the case that not everyone exposed to a particular germ gets sick, and that some people are more likely to become ill than others. Certain kinds of sickness are associated with particular places, such as the tropics, or with certain times of the year, such as the summer. Some socioeconomic groups shoulder very different disease burdens than others, even within the same society. The disease burden in urban areas can be different from the disease burden in a rural environment. A person infected with a disease germ can spread it to others, but may not show any sign of the disease.

For hundreds of years prior to the acceptance of germ theory, public health officials, scientists, physicians, and other writers had been observing and explaining the incidence and prevalence of health and disease without any awareness of disease-causing microorganisms. The Contagion collection includes a significant number of these works.

Miasmas, Zymosis, and Bad Smells

Before the last decades of the 19th century, disease was often assumed to be caused by the airborne emanations of rotting plant and animal matter, filth, and decay. These emanations were sometimes known as “miasmas.” A miasma could be local, or it could be associated with a large geographic area. A miasma could also be the temporary result of some disturbance, or it could be permanently associated with a particular place, such as a swamp. (As an example, malaria—a word that means “bad air”—was long associated with proximity to swampy environments.) Miasmas could be altered by changes in weather, season, humidity or dryness, composition of the soil, or makeup of plant species in a particular area.

Zymotic diseases were associated with fermentation, which could generate what were sometimes called “organic poisons”—tiny bits of animal or vegetable matter that could transmit disease through personal contact.

Bad smells associated with filth and decay were considered to be an essential part of their infectiousness, so eliminating the source of a bad smell could also be associated with removing a source of disease.

To become infected at all, however, a person’s humoral makeup, or “constitution,” had to be imbalanced in a way that made that person susceptible to the infection in the first place. Imbalance involved not only the bodies of individual people but also each person’s relationship to his or her environment.

Contingent Contagionism, Seasoning, and Climate

Sometimes a disease was considered contagious in some circumstances but not others. Or it might be viewed as contagious only to individuals or groups. This is sometimes known as “contingent contagionism.”

The related concept of “seasoning” arose during the periods of European colonialism and American westward expansion—roughly between the 15th and 19th centuries. Newcomers to particular climates or geographic regions were observed to become sick more readily than more “seasoned” individuals who had lived in a given area or climate over time. Once newcomers were “seasoned,” they would no longer become ill so easily.

Sin and Morality

Ideas relating sickness to personal morality have long been important in European and American thought. In the Judeo-Christian tradition, sickness has often been seen as divine punishment for sin. Cures for sexually transmitted diseases, including syphilis, have been criticized in the belief that cures would encourage immoral behavior. Moral and ethical issues associated with sex, food, drink, work, and emotions have also been connected with the possibility of contracting or spreading disease.

Puerperal Fever

Puerperal, or “child-bed” fever—a post-childbirth infection that often caused fatal septicemia in the mother—was not considered contagious until the late 19th century, even though some lying-in hospitals experienced epidemics with nearly 100% mortality.

In 1843, Oliver Wendell Holmes proposed that physicians, who typically did not wash their hands or change their clothes as they worked, were transmitting the disease from patient to patient. His idea was ridiculed.

In 1844, Ignaz Semmelweis noticed that women who gave birth at home or who delivered in his hospital with the help of midwives, rather than physicians, rarely contracted puerperal fever. He noted cases in which physicians had completed autopsies on patients dead of puerperal fever and then attended births without washing their hands. Midwives were not allowed to perform autopsies. Semmelweis experimented with various cleaning methods and the puerperal fever rate in his ward dropped signifcantly. His work was also ridiculed by physicians.

Heredity and Race

Reasons related to race and ethnicity have long been employed in explaining why particular individuals or groups become sick or appear to be resistant to certain diseases. Race and ethnicity have also been used as the basis to scapegoat particular groups for causing epidemics.

After the Germ Theory

Though the germ theory brought many fundamental changes to the understanding of diseases and epidemics, society has continued to assess contagious diseases in terms of ideas that have a much longer history. Personal susceptibilities, cleanliness, morality, social environments, race, heredity, gender, and politics continue to play a prominent role in explanations of contagion, diseases, and epidemics.


Selected Contagion Resources

This is a partial list of digitized materials available in Contagion: Historical Views of Diseases and Epidemics. For additional materials on the topic “Concepts of Contagion and Epidemics,” click here or search the collection’s Catalog and Full Text databases.

Web Pages

Cholera Epidemics in the 19th Century
Colonialism and International Medicine
Germ Theory
Humoral Theory
Robert Koch, 1843–1910
International Sanitary Conferences
Medical Geography
“Pestilence” and the Printed Books of the Late 15th Century
Public Health
Florence Nightingale, 1820–1910
Tuberculosis in Europe and North America, 1800–1922
Rudolph Virchow, 1821–1902
Max von Pettenkofer, 1818–1901
Benjamin Waterhouse, 1754–1846
The Yellow Fever Epidemic in Philadelphia, 1793


Papers of Benjamin Waterhouse, 1786–1836 (inclusive)
   ““The Effects of Cold and of Catarrh,” [Lecture], 1806
   “Small Pox,” [Lecture], Sept. 1809
Records of the American Academy of Arts and Sciences, 1775–1800
   “Considerations on the methods by which the sickening and pestilential exhalations from dead animal
   and vegetable substances are overcome,” by Samuel L. Mitchell, June 5, 1800.


Explaining Disease Transmission Before the Germ Theory

Aiton, William. Dissertations on Malaria, Contagion, and Cholera: Explaining the Principles Which Regulate Endemic, Epidemic, & Contagious Diseases, With a View to Their Prevention: Intended as a Guide to Magistrates, Clergymen and Heads of Families. London: Longman, Rees, Orme, Brown, Green & Longman, 1832.
Frascatoro, Girolamo. De sympathia et Antipathia Rerum Liber Unus; De Contagione et Contagiosis Morbis et Curatione Libri III. Venetiis: Apud heredes Lucaeantonij Iuntae Florentini, MDXLVI [1546].
Maclean, Charles. Evils of Quarantine Laws, and Non-Existence of Pestilential Contagion: Deduced from the Phaenomena of the Plague of the Levant, the Yellow Fever of Spain, and the Cholera Morbus of Asia. London: Printed for T. and G. Underwood: Callow and Wilson: Burgess and Hill: Anderson: Cox and Son: E. Wilson; Edinburgh: A. Black; Glasgow: Wardlaw and Cunningham; Dublin: Hodges and Macarthur; Philadephia: Carry and Lea, 1824 (London: Printed by Richard Taylor).
Rogers, Joseph. An Essay on Epidemic Diseases: and More Particularly on the Endemial Epidemics of the City of Cork, Such as Fevers and Small-Pox, But More Professedly on the Endemial Epidemic Fever of the Year MDCCXXXI, With an Attempt to Account for the General and Special Causes Producing the Same…. Dublin: Printed by S. Powell, for W. Smith, Bookseller, 1734.
Smith, Southwood. The Common Nature of Epidemics, and Their Relation to Climate and Civilization; also, Remarks on Contagion and Quarantine: From Writings and Official Reports. Philadelphia: Lippincott, 1866.

Miasmas, Zymosis, and Bad Smells

Carroll, Alfred Ludlow. The Question of Quarantine: The Nature and Prevention of Communicable Zymotic Diseases. New York: Leypoldt, 1872.
France. Commission d'études des Odeurs de Paris. Rapport Préliminaire sur les Causes des émanations Odorantes de Paris et de la Banlieue. Paris: Impr. et Libr. Centrales des Chemins de Fer, Impr. Chaix, 1896.
Osgood, Charles. The Causes, Treatment, and Cure of Fever and Ague, and Other Diseases of Bilious Climates. 19th ed. New York: 1855.

Contingent Contagionism, Seasoning, and Climate

Chalmers, Lionel. An Account of the Weather and Diseases of South-Carolina. London: Printed for Edward and Charles Dilly, MDCCLXXVI [1776].
Dunglison, Robley. Human Health, or, The Influence of Atmosphere and Locality: Change of Air and Climate, Seasons, Food, Clothing, Bathing and Mineral Springs, Exercise, Sleep, Corporeal and Intellectual Pursuits, &c. &c. on Healthy Man: Constituting Elements of Hygiene. Philadelphia: Lea & Blanchard, 1844.
Pettenkofer, Max von. Cholera: How to Prevent and Resist It; from the German, translated (with introduction and appendix on the International Cholera-Conference [sic] of Vienna) by Thomas Whiteside Hime; revised by Dr. von Pettenkofer. London: Baillière, Tindall, & Cox, 1883.

Sin and Morality

Dewey, Orville. A Sermon on the Moral Uses of the Pestilence, Denominated Asiatic Cholera: Delivered on Fast-Day, August 9, 1832. New Bedford?: 1832 (New-Bedford: Printed by B.T. Congdon).
Rosewell, Thomas. The Pestilence, a Punishment for Public Sins: A Sermon Preached in the Middle Dutch Church, Nov. 17, 1822, After the Cessation of the Yellow Fever Which Prevailed in New-York in 1822. New York: H. Sage, 1823.
Strong, Paschal N. The Causes & Cure of the Pestilence. London: printed in the year MDCLXV [1665].
Transactions of the American Society of Sanitary and Moral Prophylaxis. New York: The Society, 1906–1910.

Puerperal Fever

Campbell, William. A Treatise on the Epidemic Puerperal Fever as It Prevailed in Edinburgh in 1821–22: To Which Is Added, an Appendix, Containing the Essay of the Late Dr. Gordon on the Puerperal Fever of Aberdeen in 1789–90–91–92. Edinburgh: Printed for Bell & Bradfute; London: Longman, Hurst, Rees, Orme, & Brown; Dublin: Hodges & McArthur, 1822.
Holmes, Oliver Wendell, 1809–1894. The Contagiousness of Puerperal Fever. Boston: Boston Society for Medical Improvement, 1843.
Semmelweis, Ignác Fülöp. Die Aetiologie, der Begriff und die Prophylaxis des Kindbettfiebers. Pest: C.A. Hartleben’s Verlags-Expedition, 1861.

Heredity and Race

Atkinson, I. Edmondson (Isaac Edmondson). Early Syphilis in the Negro. Baltimore: J.H. Foster, [1877].
Thompson, Reginald E. The Different Aspects of Family Phthisis: In Relation Especially to Heredity and Life Assurance. London: Smith, Elder, 1884.
Bowditch, Henry I. Is Consumption Ever Contagious, or Communicated by One Person to Another in Any Manner? Boston : [s.n.], 1864.


The following sources were used in writing this page.

Ackerknecht, Erwin. “Anticontagionism Between 1821 and 1867.” Bulletin of the History of Medicine, 22 (1948), 562–93.
Baldwin, Peter. Contagion and the State in Europe, 1830–1930. Cambridge: Cambridge University Press, 2005.
Barnes, David S. The Great Stink of Paris and the Nineteenth–Century Struggle Against Filth and Germs. Baltimore: Johns Hopkins University Press, 2006.
Barnes, David S. The Making of a Social Disease: Tuberculosis in Nineteenth-Century France. Chicago: University of Chicago Press: 1995.
Cooter, Roger. “Anticontagionism and History’s Medical Record.” In Peter Wright and Andrew Treacher, Eds., The Problem of Medical Knowledge: Examining the Social Construction of Medicine, pp. 87-108. Edinburgh: Edinburgh University Press, 1982.
Delaporte, Francois, trans. Arthur Goldhammer. Disease and Civilization: The Cholera in Paris, 1832. Cambridge, MA, and London: MIT Press, 1986.


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