On the first day of January, 1820, physicians elected by medical societies and colleges across the United States met in the Capitol, in Washington, to do something no earlier effort had managed: give the whole profession one agreed, national answer to what a given medicine actually was. Delegates came from the northern, middle, and southern districts of the country; the western district was not represented. Only two finished pharmacopoeias were on the table that day, one written by the northern district's physicians and one by the middle district's. The convention's task was to compare the two in detail and merge them into a single national work.
The convention existed because, as its own preface explained later that year, American medicine had no book of that kind that belonged to the whole profession. A New York hospital had published its own pharmacopoeia in 1816; the Massachusetts Medical Society had published one in 1808; and beyond these, physicians and druggists across the country freely used whichever imported British or French pharmacopoeia a given shop happened to stock. A doctor who wrote a prescription by a drug's name was trusting that the apothecary filling it shared his idea of what that name meant. Nothing guaranteed it. The preface said so without hedging: the physician, it said, was exposed, unconsciously, to administer to his patient medicines, essentially different from those which his judgment has prescribed.
The delegates spent the convention comparing the two submitted pharmacopoeias article by article and consolidating them into one. They elected Samuel L. Mitchell president and Thomas T. Hewson secretary, then appointed a committee of five, Lyman Spalding among them, to prepare the merged text for the printer. It appeared that December, printed in Boston for Charles Ewer, under the title The Pharmacopoeia of the United States of America, by the authority of the medical societies and colleges. Before adjourning, the delegates wrote their own renewal into the record: a new convention, in Washington, every ten years, charged with revising whatever this first one had gotten wrong.
The habit it wrote down, not the ten-year interval itself, is what lasted. The convention's successor, now called the United States Pharmacopeia, says of its own compendium that it is continuously revised, rather than waiting on a single edition every ten years. Federal law still enforces what the result says: the Federal Food, Drug, and Cosmetic Act treats a medicine sold under a name the Pharmacopeia recognizes as adulterated if its strength, quality, or purity falls short of what that book specifies, unless the difference is plainly stated on the label. A single national answer to what a drug is turned out to need upkeep, not just a publication date.
No convention, and no law written after it, can make an apothecary honest by decree. What has lasted since that January in the Capitol is narrower and more durable than good intentions: a habit of checking, repeated on a fixed schedule, so that the name on a prescription and the substance in the bottle keep meaning the same thing.