Benjamin Rush on Malaria in Pennsylvannia, 1785

Benjamin Rush was the best known physician in early America. In the second volume of the Transactions of the American Philosophical Society, Rush wrote an essay giving his views on the increase of bilious and intermittent fevers (malaria) in Pennsylvania in recent years.

Rush outlined three reasons for the increase:

  1. A proliferation of mill-ponds and the blockage of free-flowing streams to create these mill-ponds.
  2. Cutting of forests.
  3. Unequal rainfall in the previous seven years

Rush primarily focuses on deforestation as the cause for the increased malaria. He dwells quite a bit on his recollections that these fevers used to only occur with a half mile of creeks and rivers but can now be found up to ten miles from the river.

“It has been remarked that intermittents on the shores of the Susquehannah have kept an exact pace with the passages which have been opened up for the propagation of marsh effluvia, by cutting down trees that formerly grew in the neighborhood. … I beg a distinction be made here between clearing and cultivating a country. While clearing a country makes it sickly in a manner that has been mentioned, cultivating a country, that is, draining swamps, destroying weeds, burning brush,  and exhaling an unwholesome or superfluous moisture of the earth by means of frequent crops of grain, grasses and vegetables of all kinds, render it healthy. I could mention, in support of these facts, countries in the United States, which have passed through each of the stages that have been described. The first settlers received these countries from the hands of nature pure and healthy. Fevers soon followed their improvements, nor where they finally banished, until the higher degrees of cultivation that have been named took place. I confine myself to those countries only where the salutary effects of cultivation were not rendered abortive by the neighborhood of mill-ponds.” (Rush,  206-207)

Rush is clearly linking all forms of shallow, standing water with the occurence of malaria, then called bilious fever or intermittent fever.  Mosquitoes had not yet been identified as the vectors of malaria.

From the 13th and 19th centuries, Malaria went by several names: ague, ague and fever, bilious fever, intermittent fever, remittent fever, tertian fever, quartan (fever), marsh fever (England), autumnal fever, swamp fever, and blackwater fever. The Italian name for the fever, malaria, meaning bad-air, did not become nearly universally accepted until at least c. 1900.

Interestingly one of the supporting observations Rush gives for his theory on the relationship between water and malaria, is the  appearance of Egyptian fevers when the flood water recedes. Rush is still supporting the miasma theory of illness. He contends that the Egyptians are safe while the flood waters are present because the water is covering the earth so that it can’t release its sickly vapors. Later when the flood recedes the earth is moist but not covered,  the sickly vapors can be released to cause  the fevers. (As discussed before, one of the fevers that followed Egyptian floods was actually plague, although King Tut’s malaria indicates that it was present in some part of early Egypt.)

Rush’s suggestions for decreasing malaria in Pennsylvania include planting more trees around mill ponds. He claims to know of cases were families were saved from fevers by having a copse of trees between the mill-pond and their home. He suggests that the trees give mechanical and chemical protection. Mechanical protection comes from shading the water, preventing the production of bad air and by blocking the passage of vapors from the pond. Chemical protection comes from the trees ability to absorb unhealthy vapors and release purified air called “‘deflogisticated’ air”. Rush claims that experiments by Mr. Ingenhausz have proven that willow trees clean the air better than other types of trees.

His second suggestion for reducing the recent fevers is to make sure that cultivation kept up with the clearing of the land.

“Nature has in this instance connected our duty, interest and health together. Let every spot covered with moisture from which wood has been cut, be carefully drained, and afterwards be ploughed and sowed with grass feed; let weeds of all kinds be destroyed, and let the waters be so directed as to prevent their stagnation in any part of their course.” (Rush,  209)

Rush knows that these suggestions will take some time to implement so he makes more suggestions for the meantime.

  1. Fire, smoke or heat destroys the ill effects of marsh miasma on the human body. Rush advises large fires be lit every night between homes and the sources of marsh vapors until there have been two or three frosts. He also advises that fires be kept lit during the ‘sickly season’ in sleeping rooms for the same reason even when the heat is such that the windows must be kept open.
  2. He advises people in sickly situations to wear wool or cotton rather than linen. He claims that the most sickly parts of Jamaica have been improved since the people began wearing wool or cotton rather than linen. He also reports that during the war (the revolution) officers were kept healthy by wearing woolen shirts or waistcoats against the skin. He notes that the British Parliament requires that the dead in Britain be buried in a woolen shirt or winding sheet. Rush contends they would be better served by requiring the living to wear wool and wrap the dead in linen.
  3. The sickly summer season is the time for generous food and drinking wine or beer rather than water or spirits. Rush admits that vegetables do not cause fevers but believes because of general weakness during the sickly season more animal products should be eaten. For some reason though he thinks salted meat is better than fresh meat in the summer.
  4. Avoid the evening air under all circumstances. Drink “bitters” before breathing even the early morning air. (These bitters seem to be bitter teas made from wood products like wormwood or willow bark.) He remarks that bitters made with wine or spirits can’t be consumed in enough volume to help without intoxication.
  5. Clean linens and wash frequently. He claims that adding salt to wash water in Jamaica decreased disease. Offal should be removed from near the house but dung from domestic animals can be excepted. “Nature, which made man and these animals, equally necessary to each others subsistence, has kindly prevented any inconvenience from their living together” (Rush, 212). He believes that domestic dung/manure counteracts the effects of marsh vapors. He notes that European cottagers often live in the same building with their cattle and remain healthy. Rush claims that areas of Philadelphia with livery stables have fewer fevers.

Although Rush does not recognize the role of mosquitoes in spreading malaria, his advice mostly decreases mosquito bites. Smoke, thicker clothing, cleanliness and avoiding night air should all decrease (but not eliminate) mosquito bites. Keeping domestic animals nearby will give the mosquitoes targets other than humans. Avoiding night air, burning fires to drive away mosquitoes, and planting willow trees near ponds remained part of American folk practices for generations after the malaria was gone.



Benjamin Rush, (16 Dec 1785)  “An inquiry into the cause of the increase in bilious and intermittent fevers in Pennsylvania with hints for preventing them.” Transactions of the American Philosophic Society, vol. 2, p. 206-212.

Benjamin Rush, Professor of Chemistry at the University of Pennsylvania, read this paper on 16 December 1785.

For more information on malaria in early America see these papers:

Kukla, Jon. 1986. “Kentish Agues and American Distempers: The Transmission of Malaria from England to Virginia in the Seventeenth Century” Southern Studies 25(2): 135-147.

Rutman, Darret B and Anita H. 1976. “Of Agues and Fevers: Malaria in the Early Chesapeake” The William and Mary Quarterly. Third series.  33 (1): 31-60.

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