A New Way to Study the Human Body
In the mid nineteenth century, a French neurologist in Paris carried out unusual experiments that drew the attention of physicians, artists, and later Charles Darwin. His name was Guillaume Duchenne de Boulogne. He used electrical currents on living subjects to trigger specific muscle contractions, then photographed the results. These images showed facial expressions created by direct stimulation of individual muscles. His work became one of the first scientific uses of photography in medicine.
Electrization Localisée
Duchenne first experimented with electrified needles placed beneath the skin, but soon developed a milder, non-invasive method that used faradic current on the surface of the skin. He called it localized electrization. By applying two metal probes to different points on the face, he could activate particular muscles while the subject sat still. He performed these demonstrations at the Salpêtrière in Paris, a major medical center that provided him access to patients and clinical observation.
To record each result, Duchenne worked with photographer Adrien Tournachon. Photography had recently been invented, and the camera allowed a precise record of muscular movement. Duchenne believed drawings were not fast enough to capture rapid changes in expression, so every contraction was photographed as it appeared in real time. These images later formed the basis of an illustrated atlas published in 1862, titled Mécanisme de la Physionomie Humaine.
The Old Man and the Camera
One of Duchenne’s most recognizable subjects was an elderly man with facial anesthesia. Because the man could not feel pain in parts of his face, Duchenne applied faradic current without causing discomfort. By activating single muscles, Duchenne could photograph expressions such as fear, joy, surprise, or disgust. In many images, the man appears with one side of the face showing one expression and the other side showing another. Duchenne instructed readers to study each half separately.
He also worked with a young woman who appeared in plates for his aesthetic section. In these sessions he created scenes such as a prayerful nun or a grieving mother. The settings included props, arranged poses, and dramatic lighting. The electric probes remained the source of every expression.
Impact in Medicine and Science
Alongside facial experiments, Duchenne introduced clinical photography into neurology. He helped develop nerve conduction tests and performed the first diagnostic muscle biopsies with an instrument that physicians later called Duchenne’s trocar. His research on weakened muscles led to medical descriptions that now include Duchenne muscular dystrophy.
In 1872 Charles Darwin published The Expression of the Emotions in Man and Animals. Darwin used several of Duchenne’s photographs to support his own study of human and animal behavior. Duchenne died in Paris in 1875. His books, atlases, and photographs became reference points for neurologists and researchers who continued to study muscular movement and electrical stimulation in the human body.
In a quiet room in Paris, a neurologist asked his patients to stay still while electric probes touched their skin.
The moment the current hit, their faces twisted into vivid expressions, and a camera captured it.
These images were not acted.
They were induced…🧵👇 pic.twitter.com/hV7GPbovJR
— Fascinating True Stories (@FascinatingTrue) November 4, 2025