1855 · John Snow
On the Mode of Communication of Cholera, 2nd ed.
What this work is
Snow's 1855 book on how cholera spreads. He records where each victim lived in London and which water company supplied the house. Customers of the company drawing sewage-laden water from the Thames died at several times the rate of customers whose company drew cleaner water upstream. He concludes that cholera passes through water fouled by the sick.
Then and now
Snow showed that cholera deaths in the same streets tracked which company's pipe fed the house. Germ theory and public health cite him as founding proof that a microbe in water causes cholera. He counted deaths and pipes, and nobody has seen the microbe cause the disease.
Verdict
SCIENTIFIC
The work follows the scientific method and does not operate inside a theoretical framework. The verdict is scientific.
1·This work · no theoretical framework
SCIENTIFIC
Follows the scientific method. No theoretical framework attached.
2·Paradigm · Basic Epidemiological Comparison
NOT APPLICABLE
No theoretical framework. The study verdict decides.
How the verdict is decided
This work does not operate inside a theoretical framework. Using hospital records, billing codes, or diagnostic names as labels on visible events is not the same as depending on that framework. The verdict is the work methodology score alone.
1·This work
Did this work test its claim with methods that are independent, falsifiable, and non-circular?
SCIENTIFIC
This study claims that cholera spreads by swallowing water contaminated with the evacuations of cholera patients, shown by counting deaths street by street and comparing people supplied by two different water companies. All three tests pass.
Independently Verifiable
Pass
Snow counted dead people at their addresses and checked which company's pipe supplied each house, and either step can be redone by anyone who thinks cholera comes from bad air.
Falsifiable
Pass
If Lambeth customers had kept dying at the same rate as Southwark and Vauxhall customers after Lambeth moved its intake upstream, the water claim would have been falsified, and the miasma-majority profession was waiting to bury it.
Non-Circular
Pass
The water company records and the death registrations were built for billing and burial, so no instrument in this inquiry was designed to find waterborne transmission in advance.
Why
Dead people at addresses and the company pipe to each house can be recounted by anyone. If Lambeth's customers had kept dying at the same rate after their company moved its intake, the water claim would have been falsified. Company and burial records were kept for billing and burial, not to prove waterborne disease.
2·Paradigm · Basic Epidemiological Comparison
The three tests do not apply. There is no theoretical framework.
NOT APPLICABLE
Why
Snow's explanation, that a self-multiplying poison in the gut passes out in the evacuations and travels through water, is his interpretation layered on top. The method underneath does not need it. He compared dead people against pipes, and that comparison means the same thing whether you believe in miasma, in Snow's poison, or in nothing at all. Because the method is arithmetic on visible events, there is no framework here to score. The study verdict stands on its own.
From the work
In 1832 there were 418 deaths from cholera out of a population of 11,606, being at the rate of 360 in 10,000, or 1 in every 28 of the inhabitants.
Preston and Oldham, in Lancashire, are supplied with water from surface drainage on the neighbouring hills, and there was scarcely any cholera at either of these places in 1849.
As regards the date of attack, I was able to obtain it with great precision, through the kindness of Mr. Sibley, in upwards of eighty deaths which occurred in Middlesex Hospital; for the hour of admission was entered in the hospital books, as well as the previous duration of the illness.