"The plural of anecdote is not data and even the most intuitively obvious medical beliefs must be tested"

The German philosopher Hegel said, “We learn from history that we don’t learn from history.” “Homeopathy and Its Kindred Delusions” is a remarkable little book based on two lectures Oliver Wendell Holmes gave in 1842. It is a masterful debunking of homeopathy. If his lessons had been taken to heart, homeopathy would not have survived and we could have avoided a great number of other medical delusions that continue to plague us today, both from charlatans and from well-meaning advocates who lack Holmes’ critical thinking skills.

To realize just how remarkable this book is, imagine the world of 1842. Samuel Hahnemann, the inventor of homeopathy, was still alive. Roentgen wouldn’t discover x-rays until 1895. The germ theory was not yet established. Semmelweis wouldn’t make his observations on puerperal fever until 3 years later. It wasn’t until 1854 that John Snow removed the Broad Street pump handle and stopped a cholera epidemic. Koch’s postulates for determining infectious causes of disease weren’t published until 1890. Doctors didn’t wash their hands or use sterile precautions for surgery. Bloodletting to “balance the humors“ was still a common practice. The randomized placebo-controlled trial wouldn’t appear for another century. Contemporary medicine often did more harm than good. In fact, Holmes himself famously quipped “I firmly believe that if the whole materia medica could be sunk to the bottom of the sea, it would be all the better for mankind and all the worse for the fishes.”

Oliver Wendell Holmes did not have any of the advantages of modern medical science, but he did have a good brain and knew how to use it. He begins by saying that stories of cures are of little value because of the fluctuations of disease and the fallacies of observation, a lesson that today’s proponents of questionable treatments have yet to learn. We are constantly having to tell them that the plural of anecdote is not data and that even the most intuitively obvious medical beliefs must be tested. Holmes points out that ineffective treatments commonly appear to benefit patients through an influence on their imaginations, but advocating them is as deceptive and unethical as passing counterfeit money.

In his first lecture, Holmes reviews four nonsensical treatments to illustrate “the fallacy of popular belief and the uncertainty of asserted facts in medical experience.” The kings of England used to touch people by the thousands to cure scrofula, the weapon ointment was applied to weapons to heal the wounds they had caused, the estimable Bishop Berkeley promoted tar-water as a panacea for everything from smallpox to asthma, and patients were stroked with metallic rods, Perkins’ tractors, to relieve a variety of symptoms. These delusions were widely accepted over varying periods of time by the public, by respected clergymen, and even by doctors.