The Writer's Almanac with Garrison Keillor

The Constitutional Convention was scheduled to convene in Philadelphia on this date in 1787. The date had been agreed upon the previous fall, in order to address the flaws of the Articles of Confederation and to "form a more perfect union." There was great concern over the Articles. They didn't provide against foreign attacks, secure harmony to the states, or defend against encroachments; nor were they superior to the constitutions of individual states. George Washington felt they were "liable to be overturned by every blast."

But when May 14 arrived, only 8 of the 55 delegates showed up. James Madison wrote to
Thomas Jefferson that bad weather had kept many from arriving on time.

By May 25, there were finally enough delegates present—30 out of 55—and things got underway. One of the first things the convention established was its secrecy rule, "that nothing spoken in the house be printed, or otherwise published or communicated without leave." The rule went so far as to require the windows to remain closed and the heavy draperies pulled shut, much to the discomfort of the formally dressed, bewigged, and powdered delegates who were locked indoors all summer with no prospect of cooling breezes.

One of the convention's key arguments was over representation. Federalists from large, wealthy states believed that share in government should be based on wealth and population. Anti-Federalists from smaller states, believed each state should have an equal say. Neither side would back down, and finally the Connecticut Compromise was reached: a bicameral legislature. In the upper house of Congress, each state would receive an equal number of representatives; proportional representation would be the rule of the lower house. Another sticking point came in determining a state's population. Not everyone agreed on whether slaves were people or property. After much haggling, slaves were awarded three-fifths personhood, and were taxed as property.

The convention also worked out whether the presidency would be a single office or divided among three people; what would constitute an impeachable offense; and how federal judges were to be appointed. After four months, the convention produced the United States Constitution, the supreme law of the country, signed by 39 of the delegates.

The first safe smallpox vaccine was administered on this date in 1796. Smallpox was a devastating illness; in the 18th century alone, it claimed the lives of 60 million people. Doctors and scientists had used inoculation—introducing the smallpox virus under the skin—to try to create a mild case that the patient could survive, building future immunity. This method was fairly successful, but risky. Some patients caught the disease and died, and some became carriers, passing the disease to others.

Edward Jenner was one of thousands of English children who had been inoculated with live smallpox in 1757. He developed a mild case of the disease and recovered. He grew up to become a doctor, and in the course of his practice he heard a milkmaid brag that she could never catch smallpox because she'd already caught cowpox from the cows. Cowpox was closely related to smallpox, but it had much milder effects on humans. Jenner injected fluid from a cowpox sore into the arm of James Phipps, an eight-year-old boy, and six weeks later, he injected Phipps again, this time with live smallpox. The boy showed no symptoms, because his body had developed antibodies. Jenner called the practice "vaccination," after "vacca," the Latin word for cow.

Jenner published his research at his own expense, and devoted his life to promoting the practice of vaccination. Less than 50 years later, the British government passed a law providing free smallpox vaccinations to all infants.