Primary works

These works can all be located online by searching in Google Books

Anon. A New Discovery of the Nature of the Plague . . . Contrary to the Opinion of Dr. Meade, [sic] Dr. Browne, and others, who give for the First Causes of the Plague . . . Air, Diet, and Disease

(London: T. Bickerton and J. Wilford, n.d. preface dated Aug. 31, 1721

This very rare book is not, strictly speaking, a  contagionist work. It attributed plague to "a subtle active poisonous Body or Insect, very minute ... living on and subsisting by the virulent Matter in the body ... the Air being no more to it, than it is to Birds.  The author, who frequently refers to the similar views of Richard Bradley, suggests that the smaller insects are, the faster they multiply, explaining why plague kills its victims so quickly.  He points out that inanimate particles can't move of their own accord and they become weakened, not increased in power, when they impart their qualities to another body.  Despite Mead's theory that the plague consisted of small venomous particles, bodies could not absorb particles through the pores in the skin because the body constantly exhales through them.  The fact that no epidemic had taken place in England for more than half a century despite many earthquakes, floods, storms, sieges and bad weather showed that these events did not cause the plague.  Similarly, there were many starving and sick people who did not contract plague.  In the second portion of this book, as if he had completely forgotten the argument he had just made, the author blames the bad air emanating from large, closely packed groups of people.  He suggested that the existence of many prison galleys in Marseilles led to the epidemic there and suggested that the largest source for the problem in London was the presence of many prisons within the city.  He called for the removal of criminals to prisons outside the city and for the release of debtors from debtors' prison. The vehemence of his discussion of the plight of London debtors suggests that this advice may have been self-interested, but it was probably sound advice nevertheless. Unfortunately, this work is no longer available from Google Books.

John Clark: A Collection of Papers Intended to Promote an Institution for the Cure and Prevention of Infectious Fevers in Newcastle and Other Populous Towns (Newcastle: S. Hodgson, 1802).  As the title promises, this is an anthology of papers by various authors relevant to the debate over the founding of a fever hospital in Newcastle.  The various items in the collection are separately paginated.   "Appendix  III" which is numbered as pages 79-80 of 298 in the Google Books edition consists of "Instructions and Rules to be Observed by the Patients of the Dispensary; first printed in 1791."  This is Clark's version of an "Advice to the Poor" and evidently was handed out to Dispensary patients to advise them on preventing contagion in their own homes.

M.A.C.D. [?Robert Boyle] Systme d'un Medicin Anglois sur la Cause de Toutes Les Especes de Maladies, Avec Les Surprenantes Configurations Des differentes especes de petits Insectes, qu'on voit par le moyen d'un bon Microscope dan le Sang & dan les Urines des differens Malades, & mme de tous ceux qui doivent le devenir Recueilli par M.A.C.D.  (Paris:  Alexis-Xavier-Rene Mesnier, 1726)

"The system of an English Doctor on the cause of all sorts of diseases with the surprising appearances of different species of small Insects, which can be seen by the means of a good Microscope in the Blood and in the Urine of different patients, and also in all those who will become ill"

This entertaining treatise, reported to be by a quack physician and juggler called Robert Boyle, Boile or Boil, claims to be a translation of the third part of a treatise entitled "Systems of an English Doctor, on the nature of God & of Souls, on the Generation of every thing, on the cause of all sorts of Maladies, and on their cure, collected and made intelligible... to everyone".  The author explains that he has only translated the third part because the first part (on the nature of God) would be contrary to the revealed truth of our religion, the second (on generation) would wound the modesty of the chaste, and the fourth (on medicine) would not only make all men their own doctors but also all women. 

The Google version, which is digitized from a copy in the University of Lausanne (2009) includes a sequel, "Suite du Systeme d'un Medicine Anglois, sur la Guerison des Maladies, par lequel sont indiquees les especes de Vegetaux & Mineraux, qui sont des Poisons infallibles pour tuer les differentes especes de petits Animaux, qui causent nos Maladies, Recueilli par M.A.C.D. (Paris, Mesnier: 1727)

"The sequel of the System of an English Doctor on the Cure of Illnesses, by which is indicated the sorts of Vegetables and Minerals which are unfailing poisons for kill the different species of small Animals which cause our diseases".

This attributes the earlier work to conversations the author had had with an English doctor, coming from Ispaham (Isfahan) who had been passing through Europe with the Persian Ambassador in 1715.

For the story of this work, see William Bulloch, History of Bacteriology (1938, Dover edn, New York: 1979), p. 32.


Benjamin Marten, A New Theory of Consumptions, More especially of a Phthisis or Consumption of the Lungs (London: 1720)

The first complete account of Contagium Vivum in England.  The first edition appeared in 1720; a second ed. appeared in 1722.


Richard Mead, A Short Discourse Concerning Pestilential Contagion and the Methods to be Used to Prevent it London: Printed for Sam. Buckley in Amen-Corner and Ralph Smith at the Royal-Exchange, 1720.

There were nine editions; the last was in 1744.  The book is dedicated to James Craggs, Secretary of State, who would soon become implicated in the scandal over the bursting of the South Sea Bubble.  Craggs lost his son to smallpox in  February, 1621 and died one month later of a stroke.

For more on this work, see Charles-Edward Amory Winslow, The Conquest of Epidemic Disease (Princeton, 1943) and Arnold Zuckerman, "Plague and contagionism in eighteenth-century England: the role of Richard Mead", Bulletin of the History of  Medicine 2004 Summer;78(2):273-308.


Secondary Works


H[ector] Grasset, "La thorie parasitaire et la phthisie pulmonaire au XVIIIe Sicle", France Mdicale (Nov. 17, 1899), translated by Thomas C. Minor as "The Parasitic Theory and Pulmonary Phthisis in the Eighteenth Century" Cincinnati Lancet-Clinic,  n.s. 44 93: (Jan. 6, 1900), 22-26  and (Jan. 13, 1900), 43.

This is very helpful historical review of eighteenth-century contagionist works. Unfortunately, several proper nouns are misspelled in the Minor translation, making it harder to find the article through Google searches.  As far as I know, 20th. century historians were unaware of this article. I have not been able to locate the original, French, version.





Achtman, Mark, Morelli, Giovanna, Zhu Peixuan et. al. "
Microevolution and history of the plague bacillus, Yersinia pestis"
Proc Natl Acad Sci U S A. December 21,2004 ; 101(51): 1783717842.
Published online 2004 December 14. doi: 10.1073/pnas.0408026101


Ayyadurai S, Sebbane F, Raoult D, Drancourt M. Body lice, Yersinia pestis Orientalis, and Black Death [letter]. Emerg Infect Dis [serial on the Internet]. May, 2010 .


Stephanie Haensch, Raffaella Bianucci, Michel Signoli, et. al, "Distinct Clones of Yersinia pestis Caused the Black Death" PLoS Pathog 6(10): e1001134. doi:10.1371/journal.ppat.1001134



For about the past decade, there has been a fierce debate about whether the "third pandemic" of Plague (Yersinia pestis) that broke out during the 19th. century was caused by the same agent as the earlier pandemics known as the Plague of Justinian and the Black Death. DNA analysis of cells recovered from medieval graveyards yielded some evidence that this was the case.  However, the evidence did not convince all doubters.  Some skeptics argued that the earlier pandemics did not conform to the pattern that would be found in a disease carried by rats and rat fleas and suggested that the DNA analysis had used samples contaminated in the lab.  Others argued that the epidemiology of the Black Death suggested a disease that spreads by contagion from person to person not one transmitted by rats and their fleas.  For example, the Black Death appeared in Iceland which does not have rats, and in other places that were considered too cold to sustain an epidemic of Plague.  These three articles appear to resolve the issue.  They identify two variants of Yersinia pestis as the agent of the second pandemic (1348-1750) and suggest a possible additional mechanism of transmission in the form of human lice.  Lice are also the main vectors of typhus.