miasma
ALTERNATIVE NAME: miasma (μίασμα, ancient Greek: "pollution"), a noxious form of "bad air" ("mal aria" in Medieval Italian), also known as "night air".
LANGUAGE: Not specific
TIME:
Middle ages until late nineteenth century
LOCATION:
Europe
CATEGORY: A theory of disease
DISCIPLINE: Medicine
SHORT DESCRIPTION:
Concept of bad air being the source of disease
DESCRIPTION:
The word ‘miasma’ relates to the gas released by putrefied organic matter. For centuries it was associated with disease.
The idea of corrupted air being related to corruption of the body was prevalent at the time of the Black Death in the fourteenth century when it was presumed that corrupted air degenerated into poisonous miasmas that stuck to people or were inhaled.
In the Renaissance, it was generally recognized that the plague raged in the summer and this related to the fact that in hot weather open sewers and decaying garbage smelled worse than usual. It was also thought that hot weather encouraged the breeding of seeds, particles or atoms in evil-smelling decayed matter and badly-drained land. These particles then rose into the surrounding air, and contact with this air would infect people.
The fact that people who had regular contact with carpets, wool and furs (materials friendly to fleas) were more inclined to succumb to plague than those who dealt in marble, iron or wood confirmed the idea of the stickiness of miasmas.
At the beginning of the seventeenth century, the Flemish physician Helmont* declared that the cause of the plague was a poisonous gas. At the end of that century, the English scientist Boyle* stated that diseases are caused by small particles contained in exhalations from the earth and that their rapid diffusion was responsible for epidemics.
During the eighteenth century, the study of gases led to a new fascination with the composition of air. Volta*, the Italian physicist, collected “inflammable air” (now known as methane) from the marshes around Lake Maggiore, and invented a device for analyzing air which was used by Alexander von Humboldt* and Gay-Lussac* in 1805 to show that the percentage of oxygen in air was independent of its source.
Despite the scientific advances of the eighteenth century, the miasma theory was prevalent until the last quarter of the nineteenth century. In Britain, major advances in public health during the nineteenth century arose from the continued belief of physicians in the miasma theory. Even the brilliant epidemiological work by Farr* and Snow* was based on a belief in miasma.
In America, Gorrie*, a physician treating patients with malaria, was driven to undertake his pioneering work in refrigeration during the 1840’s by his belief in the miasma theory and the need to improve the environment.
One of the most renowned surgeons in Britain (James Young Simpson, 1811-1870, Britain’s leading obstetrician and popularizer of chloroform use) defended the miasma theory and was sure that ventilating hospital operating rooms was a better remedy for preventing infection than adopting Lister’s* antiseptic techniques. By 1890 the pathogenic organisms responsible for tuberculosis, anthrax, cholera, rabies, typhoid and diphtheria had all been identified and the prevention and control of disease was no longer influenced by the miasma theory
ONELINER: Miasma theory, relating disease to bad smells
BIBLIOGRAPHY:
Cipolla, Carlo M, Miasmas and Disease, Public Health and Environment in the pre-Industrial Age, Yale University Press, New Haven and London, 1992
Mitchell, Sally, Ed., Victorian Britain,. St James Press, Chicago and London, 1988.