One possible explanation is that Twain was relating it to Salpetriere
Hospital in Paris -- a former gunpowder factory (saltpeter is a
component of gunpowder.)

"Stirring Times in Austria" was written at a time when Twain was
pondering theories of the mind. French neurologist Jean-Martin Charcot
was associated with the Salpetriere and Twain has indicated he
was familiar with the French experiments. Although she does not
mention "Stirring Times in Austria," Susan Gillman discusses
Twain's interest in Charcot's work in _Dark Twins: Imposture and
Identity in Mark Twain's America_.


Barb