Ectoplasm is a term with two very different meanings depending on the context. In paranormal lore, it refers to a mysterious substance that supposedly oozes from the body of a spirit medium during a séance, serving as physical proof of contact with the dead. In cell biology, it describes the dense outer layer of a cell’s interior fluid. The paranormal meaning is by far the more widely known, thanks largely to séance culture and movies like Ghostbusters, and it has a fascinating history of fraud, investigation, and spectacle.
Where the Term Comes From
French physician Charles Richet coined the word “ectoplasm” in 1894. Richet was a Nobel Prize-winning physiologist who also had a deep interest in psychic phenomena. He used the term to describe a viscous substance that he believed exuded from spirit mediums during trances. Interestingly, Richet didn’t think ectoplasm had anything to do with ghosts or spirits. He believed it was an external manifestation of some unknown mental power that allowed psychics to read thoughts, move objects without touching them, and perceive distant events.
The word itself combines the Greek “ektos” (outside) and “plasma” (something formed or molded). Other researchers used the term “teleplasm” for the same alleged substance, but “ectoplasm” is the name that stuck in popular culture.
What Ectoplasm Supposedly Looked Like
Descriptions from séance investigators in the early 1900s paint a bizarre picture. The substance was said to emerge from the medium’s mouth, nose, ears, fingertips, navel, and sometimes genitals. It reportedly started as amorphous, cloudy clumps of material and could appear white, grey, or dark. Observers described it as moist, cool, and viscous, sometimes resembling gauzy fabric and other times looking more like connective tissue.
Over the course of a séance, this substance was said to organize itself into more complex shapes: finger-like projections, rudimentary hands, and even doll-like faces or heads that seemed to float on cord-like tendrils still attached to the medium’s body. One investigator described seeing thick cords of the substance stretch between a medium’s hands, then spread into fringe-like sheets. Another reported feeling something cold and tongue-like brush against his hand, and later discovering a mass “like uncooked liver” on a medium’s thigh.
Mediums claimed the substance was extremely sensitive to light and could cause them physical pain if exposed to sudden brightness. This conveniently meant séances had to take place in near-total darkness, usually lit only by dim red light or the faint glow of luminous paint on a piece of cardboard.
How Investigators Studied It
Several prominent researchers took ectoplasm seriously enough to attempt scientific study. The German physician Albert von Schrenck-Notzing spent years documenting séances, photographing the substance, and even taking physical samples. His microscopic analysis of one sample found epithelial cells (skin cells), fat droplets, mucus, and cell debris. He proposed a theory called “ideoplasty,” suggesting the substance was a physical projection of the medium’s unconscious mind, essentially materialized dream-images drawn from memories and mental impressions.
Not everyone was convinced. The psychologist Albert Moll argued that researchers who vouched for ectoplasm suffered from a “morbid will to believe” that paralyzed their critical thinking. He dismissed Schrenck-Notzing’s documentation as scientifically useless, noting that even dozens of witness signatures couldn’t substitute for proper experimental controls. Some of the photographed “materializations” were later identified as imperfect reproductions of photographs from magazines the medium had previously seen.
How Mediums Faked It
The overwhelming majority of ectoplasm demonstrations turned out to be outright fraud. Mediums used a surprisingly simple toolkit to fool audiences sitting in dark rooms. Cheesecloth was the most common prop, sometimes swallowed beforehand and then slowly regurgitated during the séance. Textile products smoothed with potato starch, strips of gauze, egg white, soap mixed with gelatin, and plain muslin all made appearances as “spirit matter.”
The faces and figures that seemed to emerge from the ectoplasm were often pictures cut from magazines and pinned or stuck onto cloth. Investigators who examined photographs of supposed materializations found visible magazine cut-out edges, pins, and pieces of string. The medium Helen Duncan was caught using cheesecloth she had swallowed, along with dolls’ heads and masks. Mina “Margery” Crandon, one of the most famous American mediums, produced a “spirit hand” that turned out to be carved animal liver. The Danish medium Einer Nielsen was caught hiding fake ectoplasm in his rectum.
A Mexican magician named Carlos María de Heredia demonstrated just how simple the deception was by replicating a famous medium’s ectoplasm using nothing more than a comb, gauze, and a handkerchief.
Houdini and the Margery Séances
Harry Houdini’s investigation of Mina Crandon, known publicly as “Margery,” is one of the most famous ectoplasm debunkings in history. Houdini had originally been interested in spiritualism after trying to contact his deceased mother through mediums, but he quickly recognized that they were using the same sleight-of-hand techniques he employed in his magic act.
Houdini attended several of Margery’s séances beginning in July 1924. With each session, her supposed spirit guide “Walter” demonstrated new abilities. Houdini responded by building an elaborate restraining box that locked down Margery’s hands and feet, eliminating her ability to manipulate props. The result was a completely blank séance with no phenomena at all. In 1925, Houdini challenged Margery to appear at Boston’s Symphony Hall and produce any phenomena he couldn’t replicate, offering $10,000 in bonds. She didn’t show up. Houdini spent two nights reenacting all of her séance tricks for a packed audience. A month later, the investigating committee officially denied Margery the prize.
Ectoplasm in Pop Culture
For most people today, ectoplasm means the glowing green slime from Ghostbusters. That 1984 film transformed the concept from a gauzy, flesh-toned substance emerging from Victorian mediums into a bright, cartoonish goo left behind by ghosts. The shift was dramatic. In séance-era descriptions, ectoplasm was white or grey, tissue-like, and connected to the medium’s body. In movies and TV, it became a neon residue splattered on walls and people.
This pop-culture version is now so dominant that the original spiritualist meaning has largely faded from public awareness. While ectoplasm was once taken seriously enough to attract Nobel laureates and fill research journals, it’s now primarily a Halloween prop and a punchline.
The Cell Biology Meaning
Entirely separate from the paranormal definition, ectoplasm is a legitimate term in cell biology. It refers to the dense, gel-like outer layer of a cell’s cytoplasm (the fluid that fills the cell). This outer zone is relatively clear and free of granules compared to the inner layer, called endoplasm, which surrounds the nucleus and contains most of the cell’s internal structures.
The distinction matters most when studying amoebas and similar single-celled organisms. In these cells, the ectoplasm functions as a locomotion apparatus. The cell moves by converting its cytoplasm between the thicker gel state (ectoplasm) at the edges and the more fluid state (endoplasm) in the interior, creating a flowing motion that pushes the cell forward. The term also appears in medical contexts when describing certain cell types whose cytoplasm shows a visibly denser outer zone under a microscope.