The suffragettes were obviously ahead of their time (and rather fearsomely formidable). Isadora, who leaped around the stage in skimpy chiffon tunics and bare feet, was too weird.

The obvious person was the ballroom dancer Irene Castle. She and her husband, Vernon (more miserable little boys), had set several dancing trends: the one-step, the hesitation waltz, the tango, the turkey trot, and, of course, the Castle Walk.

Irene was pretty, and almost everything she wore had become a fad, from white satin shoes to little Dutch caps. In 1913, at the height of their popularity, she’d had her hair cut short while she was in the hospital after an appendectomy, and she’d kept it short after she got better and had worn it with a wide band that clearly foreshadowed the flappers.

She was a known fashion-setter, and she’d definitely had followers. But if she was the source, why had it taken so long to catch on? When Bo Derek’s corn-rowed hair hit movie screens in 1979, it was only a week before corn-rowed women started showing up everywhere. If Irene was the source, why hadn’t hair-bobbing become a fad in 1913? Why had it waited for nine years and a world war to become a fad?

Maybe the movies were the key. No, Mary Pickford hadn’t cut off her long curls until 1928. Had Irene and Vernon Castle done a silent film in, say, 1921?

Management was still calling on waving hands.

“I think we should have an espresso cart in the building,” Dr. Apple-gate said.

“I think we should have a workout room,” Elaine said.

“And some more stairs.”

This could go on all day, and I wanted to check and see what movies had come out in 1922. I stood up, as unobtrusively as possible, snatched a form from Flip, who had skipped our table, and ducked out the back, leafing through the form to see how long it was.