In British America, in the eighteenth century, the month of November became known for the destructive revelry of Pope's Day. It was not anti-Catholic enthusaism, however, that induced someone to fling a very large firecracker - a bomb, actually - through Cotton Mather's window on the 14th day of that month, in the year 1721. Rather, the anonymous bomber wanted to lodge a protest against a controversial new medical technique, smallpox inoculation, that the clergyman had just introduced to Boston. Like other remote European colonies, Massachusetts suffered from repeated outbreaks of the dread pox. The epidemic of 1721 infected a quarter of the city and left hundreds dead. Normally New England colonists dealt with smallpox through quarantine. Deliberately inoculating a healthy person with infectious pus in order to induce a (usually mild) case of smallpox, thus bestowing immunity on whomever survived the treatment, seemed both dangerous and perverse. That Mather learned of inoculation from Boston's African slave community further undermined his credibility in the eyes of white colonists, even though West Africans had been dealing with smallpox for centuries.
The bomb, a gunpowder-and-turpentine-filled grenade, failed to detonate, allowing Mather to die peacefully in his bed six years later. It also allowed him to read the note attached to the deadly billet-doux: "Cotton Mather, you dog, damn you, I'll inoculate you with this." Such sentiments remained common in Boston for some years thereafter. Former Bostonian Benjamin Franklin declined to inoculate his own offspring, later lamenting his decision when one died of smallpox in childhood. Military necessity obliged George Washington to inoculate the Continental Army in 1777. His soldiers might have disdained the procedure but their commander didn't allow them to vote on it. Even quarantine could provoke violence, as during riots in early 1774 against the inmates of a Boston smallpox hospital.
The notion of injecting oneself or one's children with a foreign substance, even through a very safe procedure like vaccination (inoculation with a dead or weakened microorganism), remained an uncomfortable one for many. Indeed, opposition to vaccination can be revived even in a more scientific age, and adults who religiously vaccinate their children still find the procedure creepy enough to ignore the needs of their own immune systems. How many of my readers get their flu shots every year?
Sources: Mark Peterson, "Life on the Margins: Boston's Anxieties of Influence in the Atlantic World," in Wim Klooster and Alfred Padula, eds., The Atlantic World: Essays on Slavery, Migration, and Imagination (Prentice Hall, 2005), 45-59, esp. 57-58; Pauline Maier, "Popular Uprisings and Civil Authority in Eighteenth-Century America," William and Mary Quarterly, Third Series, 27 (Jan. 1970): 3-35, esp. 5-6.