Poem from a Sci-Fi Horror Film

This short rhyme, from the novel and movie "Donovan's Brain", is a good tongue twister and pronunciation exercise of "s" and "st".

"Amidst the mists and coldest frosts
With stoutest wrists and loudest boasts,
He thrusts his fists against the posts
And still insists he sees the ghosts."

American novelist and screenwriter Curt Siodmak, who wrote the book in 1942, was born in Dresden, Germany.  Being Jewish and smart enough to see the writing on the wall, he emigrated in the early '30s.  Many of his works, such as "The Wolf Man" starring Lon Chaney, Jr. have a dark side.

The tongue twister, which plays a vital role in the plot, is an intriguing little gem.  I wonder if it is derived from a Jewish or European fable or saying.