What happens when you read The Professor and the Madman simultaneously with Eats, Shoots & Leaves?
You start really wondering about whether St. Elizabeths, the mental hospital located in our nation's capital, is spelled with or without an apostrophe. This may seem a minor point, but the historical characters creating the Oxford English Dictionary around which "The Professor.." revolves would have cared about such a question, as surely Lynne Truss, the author of "Eats, Shoots...", does.
One of the two major characters of "The Professor..." knew the facility well. Dr. Minor, who contributed a great deal to the OED, stayed at St. Elizabeths during his final years, after spending 38 years at Broadmoor asylum in England.
Wikipedia spells it without an apostrophe. But Simon Winchester, the author of "The Professor...", uses the apostrophe in every instance. The D.C. Chief Technology Officer instructs webmasters to leave the apostrophe out.
From 1858 to 1910, the official name of the hospital was the Government Hospital for the Insane. Informally, however, it was called St. Elizabeths. Dorothea Dix, the mental health reformer who played a major role in establishing St. Elizabeths, spelled it without the apostrophe. But the name "St. Elizabeths" or "St. Elizabeth's" was informal, so it's probable that lots of people called it either/or during the period of 1858 to 1910. But when Dr. Minor, the contributor to the OED and subject of Winchester's book, stayed there, it was called "St. Elizabeths," unquestionably without an apostrophe because Congress had so named it in 1910. (How Public Organizations Work, "Archetypes in Organization," Judith Lombard, page 150)
In addition to Dr. Minor, John Hinckley, who attempted to assassinate President Reagan stayed there, as did Ezra Pound following his "insane" support of the Mussolini regime during WWII. The hospital is named for St. Elizabeth of Hungary.