The Body Electric, 1840s

Emil du Bois-Reymond’s innovations for recording electrical signals from living tissue set the stage for today’s neural monitoring techniques.

Written byJef Akst
| 3 min read

Register for free to listen to this article
Listen with Speechify
0:00
3:00
Share

FAIL-SAFE FROG: To demonstrate in vivo “negative variation”—known today as a nerve signal, nerve impulse, or action potential—Emil du Bois-Reymond would secure a frog in a clamp and slice an opening in its back to access the spinal cord. He would then insert metal electrodes to stimulate whole-body tetanus, a prolonged muscle contraction, by discharging an electrical current to the central nervous system. Strips of wet blotting paper draped over the frog’s body served as the electrodes connecting the frog to a saline pool below, which was linked to a galvanometer that recorded the expected change in current. “This is not some trace observance that has to be descried amidst ambiguous conditions and cases of failure,” du Bois-Reymond wrote in the second volume of his treatise on electrophysiology, first published in 1849; “no, this is about a needle moving forty to seventy degrees, about an experiment so simple, striking, and secure in its success that, as long as I have apparatus and frogs, I volunteer to repeat it at any time, at any place, as often as desired, without it ever failing.” MAX PLANCK INSTITUTE FOR THE HISTORY OF SCIENCE; (inset) COURTESY OF GABRIEL FINKELSTEINIn 1841, German physiologist and anatomist Johannes Müller handed his student, Emil du Bois-Reymond, a research report that would change the course of his career. It was an essay by young Italian physicist Carlo Matteuci, summarizing his work using electricity to probe living organisms—namely frogs, the species of choice for most early electrophysiologists. Du Bois-Reymond “knew how to do physical experiments with electricity,” says historian Gabriel Finkelstein of the University of Colorado Denver, and the idea of applying his skills to study life called to him.

Tasked with replicating and expanding Matteuci’s work, du Bois-Reymond sought to improve upon his contemporary’s techniques. He discovered that the use of blotting paper soaked in a simple saline solution could prevent contact electricity, small currents generated by organic tissue when in contact with a metal electrode. “Those currents were artifacts of the apparatus, and they masked or confused any attempt to detect electricity in organic tissue,” says Finkelstein. Du Bois-Reymond also developed electrodes made of modeling clay, zinc, and zinc sulfate that didn’t require immersion in a buffer. But perhaps his most notable innovation was in the instrument he built to better measure the signals detected by the electrodes.

Like Matteuci, du Bois-Reymond used an electromechanical instrument known as a galvanometer, which has a ...

Interested in reading more?

Become a Member of

The Scientist Logo
Receive full access to digital editions of The Scientist, as well as TS Digest, feature stories, more than 35 years of archives, and much more!
Already a member? Login Here

Related Topics

Meet the Author

  • Jef (an unusual nickname for Jennifer) got her master’s degree from Indiana University in April 2009 studying the mating behavior of seahorses. After four years of diving off the Gulf Coast of Tampa and performing behavioral experiments at the Tennessee Aquarium in Chattanooga, she left research to pursue a career in science writing. As The Scientist's managing editor, Jef edited features and oversaw the production of the TS Digest and quarterly print magazine. In 2022, her feature on uterus transplantation earned first place in the trade category of the Awards for Excellence in Health Care Journalism. She is a member of the National Association of Science Writers.

    View Full Profile

Published In

Share
Image of small blue creatures called Nergals. Some have hearts above their heads, which signify friendship. There is one Nergal who is sneezing and losing health, which is denoted by minus one signs floating around it.
June 2025, Issue 1

Nergal Networks: Where Friendship Meets Infection

A citizen science game explores how social choices and networks can influence how an illness moves through a population.

View this Issue
An illustration of green lentiviral particles.

Maximizing Lentivirus Recovery

cytiva logo
Unraveling Complex Biology with Advanced Multiomics Technology

Unraveling Complex Biology with Five-Dimensional Multiomics

Element Bioscience Logo
Resurrecting Plant Defense Mechanisms to Avoid Crop Pathogens

Resurrecting Plant Defense Mechanisms to Avoid Crop Pathogens

Twist Bio 
The Scientist Placeholder Image

Seeing and Sorting with Confidence

BD

Products

The Scientist Placeholder Image

Waters Enhances Alliance iS HPLC System Software, Setting a New Standard for End-to-End Traceability and Data Integrity 

The Scientist Placeholder Image

Agilent Unveils the Next Generation in LC-Mass Detection: The InfinityLab Pro iQ Series

agilent-logo

Agilent Announces the Enhanced 8850 Gas Chromatograph

parse-biosciences-logo

Pioneering Cancer Plasticity Atlas will help Predict Response to Cancer Therapies