When can a documentary also be considered a horror movie?

Sure, there are loads of documentaries on the subject of horror. Some can be charming, like Every Other Day Is Halloween, C.W. Prather’s profile of horror host Count Gore De Vol. Some can inject fictional elements to blend genres, like J.T. Petty’s S&Man. Some can cover truly unsettling subjects, like Paul von Stoetzel’s Snuff: A Documentary About Killing on Camera to come close to being an actual horror movie.

But rare is the non-fiction film that through its style, design and intent properly matches the tropes of the fictional horror flick. And perhaps this creature is so rare that only one exists: Through the Weeping Glass, the new, short documentary by the Brothers Quay.

Known primarily for their nightmarish animated films of decay and rot, the Quays were commissioned to make a documentary about Philadelphia’s infamous Mütter Museum, which is devoted to medical anomalies and practices throughout the ages. Particularly some very, very dark ages.

The Quays approach their live-action filmmaking in very much the same style as their stop-motion animation. The only difference is that the many of the objects brought to simulated life in Through the Weeping Glass were at one time actually alive.

Keeping that crucial difference front and center, the Quays do their best to draw out the humanity found in the Mütter’s many exhibits. This isn’t so easy particularly since these displays tend towards the inhumane side of early medical practices.

The film draws us in initially, however, with a painfully tragic human story. A young boy, while playing with his sister, slightly injures himself. Complications from the injury develop into a rare affliction: Every fiber of his being — from his muscles to his joints and so on — slowly turns to bone so that the boy eventually becomes an immovable statue. The bizarre skeletal remains are on display in the Mütter and, as the story goes, his sister was so stricken with guilt from her involvement in her brother’s illness visited his bones every day until she died.

While the Quays, obviously, can’t animate the poor lad’s remains to bring his story to life, they instead resort to creative camerawork and recreations with actors to present a highly stylized vision of the boy’s life and legacy.

While through the documentary we learn a good deal about the Mütter’s collection, it’s really the Quay’s combination of exploring the frailty of the human body and the personal tragedies of bodies experiencing extreme affliction and torment that pushes the film into the world of horror.

The film tells this this boy’s story so intimately that one can easily imagine what it must be like to be trapped as a human statue.

That identification continues when the Quays move from the intimate stories to the more general ones that document barbaric-seeming medical practices. No writer of so-called “torture porn” screenplays could dream up some of the horrific instruments that the Mütter holds in its collection, such as the device jammed up men’s penises to break up kidney stones in a procedure that was performed sans anaesthesia.

Through the Weeping Glass is a very tight documentary, only giving a taste of everything the Mütter contains. Keeping the subject tightly focused, very little in the film feels out of sorts with the rest, such as the filmmakers’ amazement that a couple use the Mutter as a wedding chapel, which doesn’t seem so bizarre these days when unusual wedding locations are becoming the norm.

Although the wedding sequence doesn’t come across as mind-blowingly odd as the Quays intend, still, its good that they inject a little bit of normal life in a documentary that is relentlessly grim. Grim, but extremely beautiful in its lovingly stylistic way and in the way the Quays focus on the humanity to be found in sickness — and death.