Tuck shook his head. “A known quantity is exactly what it isn’t,” he crunched, mouth full of candy. “It’s been used in folk medicine for centuries, but that’s the thing about folk medicine—it’s totally unregulated. So, yeah, if it’s the Civil War you might crush it to a powder and chug it with some small beer before the doctor comes to saw your legs off, but not an exact science, no.”
