There are different ways of knowing whether a drug or a procedure works or not. At the most basic level, doctors can test it on a patient and observe the result. They can document this personal experience as a case history and share it with colleagues. If this is done thousands of times under standardized and controlled conditions, it’s a clinical trial. Such a trial yields evidence that has probabilistic character, expressed in statistical numbers. Following another approach, doctors and scientists can determine the biological mechanism underlying the new treatment. This happens in in the laboratory and it leads to evidence of a deterministic nature.
All of these approaches were used when, in the second half of the nineteenth century, surgeons in a number of countries tried to understand postoperative infection and find effective measures to fight it, as medical historian Thomas Schlich, Professor at McGill University’s Department of Social Studies of Medicine, shows in his latest research paper published in the prestigious Bulletin for the History of Medicine.
Prof. Schlich’s paper focuses on the British surgeon Joseph Lister who introduced antisepsis to kill the germs that he assumed to be the cause of wound infection. His name is associated with the nineteenth century revolution of antiseptic and aseptic surgery. Even during his lifetime Lister became one of the heroes in the pantheon of the history of modern medicine, a pioneer of science and medicine. But Lister rejected the use of numbers, as Prof. Schlich has discovered.
Even when Lister’s colleagues produced statistics and pressured him to also show statistical evidence for the success of his antiseptic methods, he kept insisting on the evidential power of case histories, combined with laboratory results. Statistics, he claimed, were a waste of his time. Coming from one of the founding figures of modern medicine, this attitude looks as puzzling to us today as it did to many of his contemporaries. Prof. Schlich resolves this apparent paradox by analyzing the history of the use of different kinds of evidence in nineteenth century surgery, demonstrating how the appreciation of statistics versus personal experience and experimental results was anchored in the practical, conceptual and cultural context of their use and how Lister’s skepticism towards statistical evidence did make sense at the time.
The article also demonstrates how subsequently, statistics were rapidly becoming the standard of evidence in surgery, now often combined with deterministic knowledge from the laboratory, and how this combination resulted in a new degree of confidence and an accelerated expansion of operative surgery. In this new context, Lister’s original reticence of spending his time compiling statistics became irrelevant and was quickly forgotten. However, the example reminds us of how different ways of knowing are linked with their particular purposes and contexts. This is as true today, at a time when new vaccines and pharmaceuticals are being tested every day, as it was at Lister’s time.
Thomas Schlich, “No Time for Statistics: Joseph Lister’s Antisepsis and Types of Knowledge in Nineteenth Century British Surgery”, Bulletin for the History of Medicine 94 (2020), 394-422. doi:10.1353/bhm.2020.0070.
January 12, 2021