The Spark of Life NPR coverage of The Spark of Life: Electricity in the Human Body by Frances Ashcroft and Ronan Mahon. News, author interviews, critics' picks and more.
NPR logo The Spark of Life

The Spark of Life

Electricity in the Human Body

by Frances Ashcroft

Hardcover, 339 pages, W. W. Norton & Co Inc, List Price: $28.95 |


Buy Featured Book

The Spark of Life
Electricity in the Human Body
Frances Ashcroft

Your purchase helps support NPR programming. How?

Book Summary

The Spark of Life presents the history of the discovery of electricity in the human body as well as present-day research and real-life stories that aim to explain death, consciousness and how these physiological electrical signals drive human thoughts, movements and lives.

Read an excerpt of this book

NPR stories about The Spark of Life

British Scientist Driven To Find 'Spark Of Life'

  • Download
  • <iframe src="" width="100%" height="290" frameborder="0" scrolling="no" title="NPR embedded audio player">
  • Transcript

Note: Book excerpts are provided by the publisher and may contain language some find offensive.

Excerpt: The Spark Of Life: Electricity In The Human Body


The Age of Wonder

I am attacked by two very opposite sects — the scientists and the
know-nothings. Both laugh at me — calling me 'the Frog's
Dancing-Master', but I know that I have discovered one of the
greatest Forces in Nature.

Luigi Galvani

'It was on a dreary night of November, that I beheld the accomplishment of my toils. With an anxiety that almost amounted to agony, I collected the instruments of life around me, that I might infuse a spark of being into the lifeless thing that lay at my feet. It was already one in the morning; the rain pattered dismally against the panes, and my candle was nearly burnt out, when, by the glimmer of the half-extinguished light, I saw the dull yellow eye of the creature open; it breathed hard, and a convulsive motion agitated its limbs.' Thus did Victor Frankenstein, in Mary Shelley's great gothic novel Frankenstein, written in 1818, record his creation of a monstrous being.

It is widely believed that electricity, in the form of a lightning bolt, was used to waken Frankenstein's creature to life. But this is a misconception that probably originates with the famous 1931 film in which Boris Karloff played the monster. Shelley herself was far more circumspect and refers only to the 'instruments of life'. Nevertheless, the novel leads us to infer that electricity was used to instill the monster with 'a spark of being', for Frankenstein gives a dramatic description of a lightning strike he witnessed as a young man that blasted an ancient oak tree to smithereens; and on inquiring about the nature of lightning from his father, he was informed it was 'Electricity'. Shelley also uses her preface to make a marriage of physiology and electricity — 'perhaps a corpse would be reanimated; galvanism had given a token of such things'.

Indeed, both Mary and her lover Percy Bysshe Shelley took a keen interest in the emerging science of electricity and its effects on the human body. Percy was a particular enthusiast having experimented with electricity at Eton, at Oxford and even at home — his sister recounts how she was terrified of being 'placed hand-in-hand round the nursery table to be electrified'. Percy was eventually sent down from Oxford for his atheist views and in 1810, during the winter vacation before his last term, he wrote to his tutor that he supposed man to be 'a mass of electrified clay possessing the power to confine, fetter and deteriorate the omnipresent intelligence of the universe'. Over 200 years later, 'electrified clay' remains a fair description of the human brain.

Although we may scoff at the idea that electricity could animate a lifeless creature and know that a lightning strike is often lethal, even today we are not immune from the idea that electricity is the spark of life. A late-night arts programme on British television (The South Bank Show) is introduced by a modified version of Michelangelo's famous painting of God creating Adam, in which an electric spark leaps from God's outstretched finger. Nor is the idea entirely fanciful for, like almost all organisms, humans are electrical machines. As this chapter shows, the development of our knowledge of 'the body electric' is intimately entwined with our understanding of electricity itself.

The Dawn of Understanding

On a dry wintry day you may receive a sharp electric shock when you open the car door or grab a metal doorknob, and find that sparks fly and crackle when you pull off a nylon shirt. Petticoats that cling to your legs, clothes fresh from the tumble dryer that stick together, hair that stands on end when you remove your hat, an electric jolt when you kiss someone, the faint battle-rattle of electric sparks, like 'tiny ghosts shooting', as you comb your hair — all these phenomena happen because static electricity builds up on our bodies. In humid atmospheres the charge dissipates quickly, but under dry conditions it can build up to thousands of volts. Close proximity to metal, however, or even another person, will cause it to discharge. Direct contact is unnecessary, as the electricity will jump the gap, generating a spark in the process. The 'electricity' between two people, that special spark, may be more than just lovers' talk.

The science of static electricity starts with the ancient Greeks' fascination with amber. It is from their word for amber, electrum, which derives from elector, meaning 'the shining one', that we get the word electron, and hence electricity. Because it was usually found washed up on the seashore, amber's origin was always considered mysterious. The historian Demostratus supposed it the crystallized urine of lynxes. Ovid tells a different story. He relates how Phaethon drove Apollo's chariot (the Sun) too close to the Earth and was struck down by Zeus to prevent a catastrophe. His grief-stricken sisters were transformed into poplar trees and shed golden tears of amber that fell into the River Eridanus in which Phaethon drowned.

Of course, we now know that amber is the petrified resin of extinct pine trees and are familiar with it as jewellery, or as the medium in which prehistoric insects have been encapsulated and perfectly preserved. But amber has another interesting and curious property. When rubbed with wool it generates static electricity, causing it to attract light, dry objects like small bits of tissue paper, feathers, specks of wheat chaff, and even your hair; this may be why Syrian women, who used decorative amber weights on the end of their spindles when spinning wool, called it the 'clutcher'. Thales of Miletus is credited with being the first to note the attractive properties of amber, in the fifth century bc, although it is hard to be certain, as his findings were only passed down orally until later philosophers, such as Theophrastus, wrote them down.

Amber generates a static charge because it attracts electrons from the atoms of the wool, becoming negatively charged in the process and leaving the wool positively charged. The charge is transferred by close contact between the amber and wool — the friction produced by rubbing is not involved, it is simply that rubbing greatly increases the area of contact between the two surfaces. Because opposite charges attract, any material that is naturally positively charged will leap towards the negatively charged amber. Conversely, as similar charges oppose one another, charging up your hair will cause each strand to repel its neighbours as much as possible, producing flyaway hair that stands on end like that of Shock-headed Peter in the German children's picture book. Parenthetically, there is nothing static about 'static' electricity. The term refers only to the fact that the positive and negative electric charges are physically separated. As soon as a positively charged material comes close enough to a negatively charged one, current will flow from one to the other — as visibly demonstrated by the leap of an electric spark.

It was William Gilbert, physician to Queen Elizabeth I, who first invented a sensitive instrument for measuring static electricity (an early electroscope). He used it to compile a long list of materials that could be electrified by rubbing. He also distinguished the attractive power of amber from that of magnets, arguing that two different phenomena are involved. Gilbert was a true scientist, for he advocated that you should not believe what you read, but instead try the experiment for yourself. He wrote, 'Our own age has produced many books about hidden, abstruse, and occult causes and wonders, in all of which amber and jet are set forth as enticing chaff; but they treat the subject in words alone, without finding any reasons or proofs from experiments, their very statements obscuring the thing in a greater fog'. Hence, he concluded, 'all their philosophy bears no fruit'. His words were prescient — present-day scientists make similar complaints about the advocates of astrology and alternative medicine.

From The Spark Of Life: Electricity In The Human Body by Frances Ashcroft. Copyright 2012 by Frances Ashcroft. Excerpted by permission of W. W. Norton & Company.