Miasma, climate, and eating fish

From a medical standpoint, the theory of humoral pathology and the miasma theory were strongly held for centuries. Both had roots dating back to the Greek physician Hippocrates, who lived nearly 2500 years ago. In humoral pathology – the theory of there being four bodily fluids – disease was interpreted as an imbalance between blood, phlegm, black bile and yellow bile. To cure disease, the balance of these liquids had to be restored using methods such as bloodletting.

The miasma theory remained prevalent until well into the 19th century. Miasma was thought to be a naturally occurring substance that arose particularly from vapours emanating from the ground or from the decay in unhealthy areas with humid and stagnant air. It was also believed that Miasma was in the air and could spread and produce disease.

As an overview was acquired of the geographic distribution of leprosy, several theories were proposed relating to climate and topography. One of the most well-known and somewhat curious theories was that ‘the overeating of fish along the coast’ was the main reason leprosy was more prevalent in coastal areas. Several doctors were of the opinion that fatty fish, liver, whale blubber and porpoise were particularly harmful.

From the late 18th to early 19th centuries, there were numerous descriptions that assumed that common people’s diet, lifestyle and lack of hygiene provided favourable conditions for leprosy and other diseases. Johan Andreas Wilhem Büchner – city physician of Bergen for around 40 years at the end of the 18th century – considered the combination of climate, poor diet and an ‘unclean and filthy treatment of the flesh’ as the main reasons for the disease among the coastal population. In his opinion, they did not only poorly prepare fish and drink bad beer and liquor, but they stayed at sea in cold weather, or in foggy, humid air, before returning to shore in the evening and crowding into small rooms in wet clothing. This created a vapour and stench that could cause any ordinary person to feel nauseous and faint, he wrote.

Venetian plague doctor. Illustration: Museo Correr, Venice.
Venetian plague physician. To protect themselves against miasma, the physicians wore beak-like masks filled with herbs.
Illustration: Musero Correr, Venice.
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