Author Topic: Miasma Theory: Trial Results  (Read 115 times)


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Miasma Theory: Trial Results
« on: December 06, 2021, 11:06:38 PM »
Copies of a recent academic paper are printed and distributed to University shelves and public libraries.

Miasma Theory: Trial Results


Miasma theory is relatively young in the field of medicine. It is the proposition that illness is caused not by conditions that imbalance humors but by the foul miasma that emanates from unclean or decaying places. It is sound, even intuitive, in theory. That which smells unpleasant is generally unsafe to consume, and best avoided. But is it well founded? One author has sought to present support for miasma theory in a case study of the flesh-rot outbreak of 702 (Falaise, M., 776). In this work the author asserts that humoral theory excludes environmental factors in explaining the origins and treatment of illness. This is a false assertion, and informs the mistakes the author makes in their later analysis. Humoral theory posits, essentially, that illness is caused by an imbalance of the four humors. This imbalance can be caused by: diet, exhaustion, injury, environmental temperature and environmental humidity. Each of these conditions is caused by the subjectís environment. Importantly, humoral theory makes specific predictions about the effects of different conditions. For example: high heat and humidity increase the sanguine humor and reduce the melancholic humor. This can cause: inflammation, fever, exhaustion and bodily decay.

Falaise asserts that the summer was hot and humid, and that the corpses of a recent battle had been left to fester in the sun resulting in a foul miasma. Those exposed to these conditions contracted flesh-rot. The astute reader will note the scientific problem with this case study immediately. Present in the example are exactly the conditions (humidity and heat) that humoral theory would predict cause illness. How, then, could we rightly claim that the miasma was causal? Falaise goes on to report that blood letting and cool water were applied but the illness continues to spread. It was not until the subjects were quarantined from the site that their conditions improved. The author presents this as proof of the inadequacy of a humoral treatment. Cool water and blood letting are the common treatments for excess sanguine humors. However, if such treatments were applied in an environment that remained both hot and humid? They would certainly remain ineffective, according to humoral theory. The illness was removed once the subjects were quarantined from the original environment. Here again the author is presenting exactly the conditions a humorist would predict were necessary to treat the illness. Finally, the author asserts that by the time subjects returned to the area the bodies were burned and only dry smoke remained in the air. This is exactly the environment condition required to help correct a humoral imbalance caused by ambient humidity.

We can reasonably conclude that the flesh-rot case study does not support miasma theory over humoral theory. But this does not mean that miasma theory does not have merit. The mistake of prior work was a failure to separate the conditions that cause miasma exposure from those which induce a humoral imbalance. After all, it is very plausible that where we typically find hot and humid conditions we also find foul miasma. Such states cause rot and therefore humoral theory may have been mistaking correlated conditions for causal conditions. We can generate competing hypotheses based on this line of reasoning:

Hypothesis 1: Wasting illness is caused by excess sanguine humors resulting from high heat and humidity.

Hypothesis 2: Wasting illness is caused by exposure to foul miasma that simply happens to be frequently present under high heat and humidity.

In my experiment, these competing hypotheses were tested.


This experiment utilised rats for their ease of acquisition and expendability. The rats were divided into three treatment groups: A, B and C. Miasma releasing substances were acquired as well as simple cages for rat housing. Group A was housed in a cage kept warm and humid by a steaming apparatus. Group B was housed in a room temperature cage of average humidity. Miasma was released from under the cage. Group C was housed in a room temperature cage of average humidity, and acted as the control group.

Rat cages were cleaned daily and inspected for signs of any rot that might introduce miasma unduly to groups A and C. The experiment was run for one week and all rats were inspected daily for signs of illness.

If illness is most frequent in group A, and the rate of illness is the same in groups B and C then hypothesis 1 is supported.

If illness is most frequent in group B, and the rate of illness is the same in groups A and C then hypothesis 2 is supported.

This way, we will be able to determine if miasma is truly causal in disease.


Group A:

Subject A1: No signs of illness. No health improvement over course of experiment.

Subject A2: Bite wound on tail had grown sceptic. This is typically ascribed to poor health from Sanguine imbalance.

Subject A3: No external signs of illness. Decreased heart rate and sluggish reaction times indicated fatigue.

Group B:

Subject B1: Expired on the seventh day. Body covered in weeping sores. Autopsy revealed mucous in the lungs and internal wasting. All signs of wasting illness.

Subject B2: Body covered in weeping sores. Weak heart rate. Signs of extreme malnourishment. Typical of wasting illness.

Subject B3: Weeping sores, one eye sealed closed by pus. Weak heart rate. Signs of extreme malnourishment. Typical of wasting illness.

Group C:

Subjects C1, C2, C3: All in better health than when they began the experiment. Healthy heart rate, quick reaction times and good weight. As is expected of the control condition.

The obvious wasting illness in group B that is absent in groups A and C supports hypothesis 2. It must be noted that group B appeared to experience a decline or maintenance of health on experiment entry. This would suggest that humoral theory remains an accurate predictor of general health, but miasma itself is the source of wasting illness previously attributed to an imbalance in the sanguine humors.


These findings represent the first empirical support for miasma theory as causal in the transmission of disease. It is likely that prior researchers mistakenly attributed the cause to sanguine imbalances caused by heat and moisture because places that are host and moist are also rich in decay and therefore miasma. It also seems likely that a sanguine imbalance made patients vulnerable to the noxious effects of miasma. While the use of animal subjects means we have not definitively proven the principle will hold with humans, these findings support expanding testing to human subjects in vivo.

Obviously, we cannot repeat this experiment with human subjects. But we can implement measures that would reduce miasma exposure in everyday life for one group, and compare their rates of illness to a group without any intervention. My proposed future trials are as follows:

1. Gating access to open sewer grates to keep children and the elderly away from a fundamental source of miasma.

2. Implementation of waste control protocols in select homes. This would mean regular disposal of food waste and excrement at a site removed from daily life. While sewer grates would be the ideal site for such practice, visitation would result in intense exposure to miasma. As such, waste will be stored in a lidded bucket kept outside. This will be collected once daily by a properly equipped plague doctor.

3. Ventilation introduced to tanneries and factories. Urine's miasma likely has an adverse effect on worker health.

4. Isolation of sick individuals with noxious sores.

This experiment opens the door to finding cheap methods to reducing disease incidence and spread significantly in our cities.

R. Camus