As a promising way of setting them right, half of the half-dozen had become members of a fantastic sect of
Convulsionists, and were even then considering within themselves whether they should foam, rage, roar, and turn cataleptic on the spot--thereby setting up a highly intelligible finger-post to the Future, for Monseigneur's guidance.
Charles Dickens, in A Tale of Two Cities, writes about the members of a sect of
Convulsionists, that would have these attacks with foam on their mouth and cataleptic seizures.
In a long letter to her Swiss correspondent Etienne Dumont, Edgeworth explained about Methodists: "Since the days of Urbain Grandier there were never such
convulsionists [sic] as these Methodist possedes--It is scarcely possible to believe that the scene is England & the time in 'our enlightened days' (Hausermann 1952: 112 [Letter to Etienne Dumont, 19 March 1821]).