a glass slide showing four snowflakes in a wood frame.

It’s a Kind of Magic

By Ginny A. Roth ~

a glass slide showing four snowflakes in a wood frame.
Snow Chrystals [sic]. ca. 1855
National Library of Medicine #101594730
Even those who live in a part of the world where it does not snow are familiar with the snowflake—a ubiquitous symbol of winter. Paper snowflakes adorn our houses during the holiday season and fall from the sky as ice crystals, unique as they are beautiful. They elicit an emotional response, be it happiness or annoyance. But what would be your reaction if you saw several snowflakes projected onto a screen at thousands of times their normal size? This is what doctors were trying to find out at St. Elizabeths Hospital when they showed a series of magic lantern slides to a room full of patients.

Magic lantern slides were a phenomenon in the mid to late 19th century and were known for their often colorful, animated and dramatic qualities. The transparent slides were projected onto a wall or screen using a lantern slide projector,  which allowed the images to be seen by a mass audience, making them particularly ideal for a wide variety of educational purposes.

This slide, from a collection of 202, was used for therapeutic purposes at St. Elizabeths Hospital, a psychiatric hospital in Washington, D.C. that opened in 1855 and was then known as the Government Hospital for the Insane.

“Picture the scene. Seated in a lecture hall, several hundred well-dressed mental patients—watched carefully by attendants—await the entrance of the medical director of their hospital. Gaslight dims and the doctor emerges, striding toward a lectern. “Today’s topic,” he announces, “is the symmetry of natural forms.” An attendant at the back hunches over an elaborate contraption that burns streams of hydrogen and oxygen over a cylinder of calcium oxide. The resulting beam of intense white light—limelight—is focused on a glass plate coated with tiny particles of silver salt affixed to the glass with albumen. Cast across the auditorium onto a screen is the perfect image of microscopically observed snow-flakes, ten feet in diameter.”
Benjamin Reiss, National Library of Medicine, Hidden Treasure.

Although the advent of moving pictures began the magic lantern slide’s decline, the slides hold a valuable place in the history of photography and continue to be a collectors item today.

Learn more about this and other rare objects from the National Library of Medicine’s historical collections in the book Hidden Treasure.

Informal portrait of Ginny RothGinny A. Roth is the Curator of Prints & Photographs in the History of Medicine Division at the National Library of Medicine.


  1. Great post! I think a lot of people have heard of “magic lantern slides,” but few have any idea of what a magic lantern was, or how they were used. This is really interesting history!

  2. Very nice post! Thanks for sharing this information. I enjoyed reading your article very much.

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