Smallpox Under a Walnut Shell

"In 1716, while searching the [Royal Society's] Philosophical Transactions... [Cotton] Mather came across a report from Turkey describing a medical procedure that produced a mild case of smallpox and left the patient immune to the disease. The process involved removing infected tissue from one person and transferring it to a healthy individual. According to the report, a medical practitioner used a sharp needle to puncture a few pocks on a young person with a mild case of smallpox and extracted a small sample of the pus, which was pressed into a clean glass vessel that was covered and kept warm until it reached the home of the inoculee. There, the practitioner made one or two small wounds in the patient's arm with a needle or lancet, inserted a drop of the pus, and gently mixed it with the oozing blood. A walnut shell provided temporary protection for the wound. In due time, pocks appeared, but fewer than in natural smallpox, and the patient seldom suffered a high fever or other serious discomforts." (10) --Amalie M. Kass, "Boston's Historic Smallpox Epidemic," Massachusetts Historical Review, Vol. 14 (2012)

Dr. Zabdiel Boylston was one of the first physicians in Boston
to use smallpox inoculation. (From: Mass Moments)

I wonder how it was first discovered that the inoculation procedure described above protected people against a more severe case of smallpox. Who was the very first physician to conduct it--and what were they thinking?! Just as important, who was the first volunteer for the experiment?

Kass describes what 17th century Bostonians believed the causes of smallpox to be. First of all, it was a punishment from God for the sins of an individual or community. Second, it was thought to result from an imbalance in bodily fluids--a conclusion based on ancient Greeks' humoral theory. Kass explains, "According to humoral theory, good health required a balance of the four elements--blood, phlegm, yellow bile, and black bile--that constituted the bodily fluids. Disease indicated that one or more of the humors was either deficient or excessive due to internal or external factors." (4)

Bostonians were in some degree aware of smallpox's contagiousness. Kass describes how quarantine measures were taken and efforts made to clean up the city's streets at the first sign of smallpox. But does it not seem to be the height of insanity to transfer the bodily fluids from a person with a deadly disease to a healthy person! What was the reasoning here for the first physician to try this out?

The reasoning seemed to have been based on the observation that once a person had had smallpox, he/she was in most cases immune from it during subsequent epidemics. The idea must have been that if the pus could be taken from the sores of a person with a mild case of it and transferred to a healthy person, then the latter would hopefully be infected with only a mild case and later become immune. Seems reasonable in a way... but, with smallpox's contagiousness being common knowledge, I sure wouldn't want to be the first guinea pig for this experiment!