We are electric, p.3
We Are Electric, page 3
It’s worth noting that before the nineteenth century, science was a lot less fussy about its academic boundaries. There was less of a demand back then on the people who studied the natural world to squeeze themselves into rigid disciplines, largely because these didn’t yet exist. All that would come later. In fact, scientists weren’t even called scientists. People who studied the natural world referred to themselves as natural philosophers, or sometimes experimental philosophers. The ultimate archetype was Alexander von Humboldt, who travelled the world studying whatever took his fancy. Men like him, and Galvani, were free to investigate whatever piqued their interest, which could (and did) range from bone structure to comparative anatomy to electricity.
Especially poorly defined were the distinctions between the physical and life sciences. Cross-field mobility was the norm. Try to categorise people who studied biology in the eighteenth century and you’d be forced to include everyone from radical theologians to physicists. One thing was clear, though. Medics – who were charged with dispensing practical remedies – did not enjoy high status, owing to an increasing awareness of the gap between their scientific airs and their actual ability to treat the sick.
A new hope
By the 1800s, we knew little more about our bodies than we had a full millennium earlier. Meanwhile, the scientific revolution had taken the understanding of electricity from strength to strength.
Like animal spirits, electrical phenomena had been observed for centuries without generating great insight. The Ancient Greeks, for example, had noticed strange stones that seemed to pull metal to them as if by an invisible force. They had seen that when lightning struck people, it often killed them. Electric eels were known to deliver a fulsome shock to their prey. Then there was amber – the insect-trapping resin that also had a strange tendency to attract bits of dust and fluff, the same way the stones attracted metal. Give the amber a vigorous little rub, you might get a little zap and see a spark. But before the seventeenth century, all these observations had not been compiled into any kind of explanatory framework.
In fact, electricity got its name long before we understood how it was involved in any of the above. The word was coined in 1600 by William Gilbert, who – in keeping with what I mentioned earlier about the disciplines – identified as a physician, physicist, and natural philosopher. He borrowed from the Ancient Greek word elektron, for amber, owing to that material’s unique ability to reliably elicit the magic spark.
The scientific revolution vastly upgraded the tools to investigate the phenomenon. In 1672, Otto von Guericke invented the first device that made it possible for scientists to generate electricity themselves: an ‘electrostatic generator’ was a glass globe you could rub with silk to accumulate a small amount of electrical charge. Touch it and you’d get a zap. (This, incidentally, is where we get the phrase ‘static electricity’. The globe trapped electricity on its surface so it wouldn’t go anywhere – it didn’t move. It was in stasis.) Electrostatic generators allowed the accumulated electricity to be dispelled in bigger jolts than amber, and that allowed people for the first time to decide how, when, and where to direct the jolts. More machines followed, some making it easier to charge the generator by having hand cranks, so your arms wouldn’t get tired from all that rubbing glass with silk. Bigger glass tubes yielded stronger jolts. The shock they generated was weak, but it was enough to start a century of parlour-game science, from the ‘kissing Venus’ – an electrified woman whose kisses stung gentlemen’s lips with a trivial zap – to young boys charged up to attract bits of paper and other flotsam as if by magic.
But all of these generators had the same problem: the very act of touching these sources of accumulated static electricity released it all in one go (which is also what’s happened when touching your doorknob zaps you with a sharp spark of pain). There was no way to store up a large quantity of electricity for later use.
About a century after the first electrostatic generator, several scientists separately converged on the idea of a special jar that could siphon the mysterious invisible substance from a generator and store it for later. To avoid the thorny question of paternity, the new invention was dubbed the Leyden jar, an indirect credit to Pieter van Musschenbroek, who did a lot of the early work in this Dutch city. Scientists competed to see who could concentrate the most electricity in their jar, because of course they did, and this had exactly the unfortunate consequences you might expect. When van Musschenbroek stuffed his Leyden jar to capacity, rather like overpacking a suitcase, it promptly exploded on him. The shock was enough to send the temporarily paralysed physicist to bed for two days.
As people got better at stuffing these increasingly capacious vessels to capacity, Leyden jar demonstrations grew progressively more dramatic, from a crowd of 200 monks connected by lengths of iron wire and shocked by a single Leyden jar, to a practical joke in which a specially designed wine glass was electrified for the amusement of picnic guests (less fun for its unfortunate target).7 Though high society loved these demonstrations, even they agreed that electricity was at best a novelty, and no one could quite deduce how this circus of wonders might prove useful . . . until the mid-1740s, when a Scottish electric showman called Dr Spencer sent his apparatus to the Philadelphia residence of a young Benjamin Franklin.8
Franklin is often credited with single-handedly turning the carnival of electricity into a science. And while it is a bit more complicated than that, Franklin’s famous kite demonstration did begin the unification process that proved that different electrical phenomena – lightning, amber, electrostatic generators – were just different manifestations of the same ethereal substance.
Franklin – famous polymath and politician – was among the vanguard of investigators trying to develop a grand unified theory of electricity that would link ‘natural electricity’ (lightning) to the stuff produced by generators and stuffed into Leyden jars (‘artificial electricity’). He attached a key to a long string, suspended by a kite, during a lightning storm. If he could charge a Leyden jar with the proceeds of a lightning storm, his point would be proved. It was a stupendously dangerous experiment, but it worked so well that kids are still forced to read about it in school. Upshot: lightning was electricity.
Franklin’s experiment was hugely consequential and helped pave the way for a new understanding that was formalised into a branch of science, whose practitioners referred to themselves as electricians. (This word carried a rather more glamorous connotation back then – you can think of eighteenth-century electricians as the ‘rocket scientists’ of their day.) What’s more, there was now an understanding of electricity as an invisible fluid that could be collected in a jar, cross vast distances, and travel along strings, hollow or not.
What else was electricity? By 1776, people had begun to wonder if this ‘immaterial fluid’ wasn’t germane to those animal spirits everyone had been wondering about. That year, the notion got its first bit of supporting evidence when John Walsh experimented with an electric eel.
Walsh was a classic natural philosopher: colonel, MP in the House of Commons, all-round rich person. He moved in the same circles as Franklin, who was just starting to cultivate an obsession with electric fish. After their electrical organs had been described, Franklin became convinced that the shock the creature delivered was another manifestation of the phenomenon of electricity, so he convinced Walsh to ‘devote his scientific energies’ (read: a boatload of his ample fortune) to devising experiments that would prove ‘fish electricity’ was real.9
The way to do that was to put an electric fish into a dark room and get it to deliver its jolt – in the hope that doing so would yield a visible spark. That would be the smoking gun. Incredibly, it seems Walsh was able to do it. Several historical accounts by people deep in the audience at his 1776 demonstration reported this convincing evidence that electric eels were, in fact, electric. The British Evening Post reported ‘vivid flashes’.
While the experiment didn’t provide any direct evidence of a link between ‘fish electricity’ and anything that might be involved in human processes, the idea was out there nonetheless: a form of electricity might be at work in the action of nerves and muscles. If an eel could make a spark, perhaps we could create our own internal sparks.
And that’s how electricity found Luigi Galvani.
The man who wanted to know God’s secret
Historians don’t know very much about Luigi Galvani’s family and youth. We do know that he was born in 1737 in the Papal State of Bologna, a wealthy and progressive state of Italy. According to the historian Marco Bresadola, Galvani was born into a merchant family; his father, Domenico, was a goldsmith on his fourth wife (Barbara) and second round of children by the time Luigi entered the world.10 The Galvanis had enough money to send more than one of their children to obtain a university education, which was not an inconsiderable expense. But having a scholar in the family was a mark of social standing and prestige for the merchant classes, so Domenico trotted his kids off to school.
Luigi was initially opposed to this fate. He was a dreamy child who preferred family life to Bolognese student antics. What he liked most was spending time in conversation with the monks at a monastery near Bologna, who were tasked with counselling the dying in their final hours.11 Galvani was fascinated by the insights the monks brought back from their time with people at the edge of life and death. There, Galvani also absorbed the values and ideals of the progressive Catholic Enlightenment, including the reigning Pope’s theories of ‘public happiness’. Instead of focusing on ritual and splendour, as many of his predecessors had, the progressive Benedict XIV tried to inspire his citizens’ devotion by actually improving their lives, which took the form of civil engineering projects like public drainage, but also improvements to the education system, including stocking universities with the latest tools, including electrical ones.12 He redefined faith as charitable action, not competitive superstition.
This philosophy resonated with the young Galvani, and when he was a teenager, he asked to join the order. However, his family convinced the monks to talk him out of it, eager to divert this obviously gifted child onto a more socially mobile track. So Galvani withdrew his inquiry and instead enrolled at the University of Bologna to study medicine and philosophy. (He also studied chemistry, physics, and surgery.) His father was right about his potential – Galvani would go on to write twenty theses just about the structure, development, and pathology of bones. After obtaining his doctorate, Galvani began to research and lecture in anatomy at the university. Though not a natural extrovert, he was a popular lecturer.13 He was one of the first professors to enliven his talks with experiments, and his enthusiasm was so infectious and his teachings so accessible that students from the neighbouring arts academy often crowded into the room. Galvani was awarded a fast succession of academic positions and honours at the University of Bologna, and soon held a concurrent appointment with the Institute of Sciences of Bologna, one of the first modern experimental institutions in Europe.
But he would never quite lose sight of the road not taken – according to all accounts, he remained a devout Catholic to the end of his life. If he couldn’t devote himself to God in the monastery, he at least wanted to do it in the laboratory. He lived his principles as best he could, turning his work into an expression of his devotion. In addition to his post at the university, he became a practising physician at the local hospital. He gave preferential treatment to people in extreme poverty – especially women. As an obstetrician, Galvani nurtured a deep, abiding obsession with creation. More than anything he wanted to understand the scientific underpinnings of how God had given humans the spark of life.
Galvani was in the ideal place, at the ideal time. Founded in 1088, not only was the University of Bologna the oldest university in Europe, it was also the most progressive and forward-thinking. For example, the university had recently promoted Laura Bassi, its first female lecturer in experimental physics. Bassi was a prodigy who taught Newtonian physics from her home laboratory and established ties with electricians all over the world, including Benjamin Franklin and Giambattista Beccaria, who were considered the leading electrical theorists of the time.14 This network ensured the university was at the vanguard of this important new phenomenon. Unlike some of his contemporaries, Galvani was in no way scandalised by women in authority or in the sciences writ large; while no one could attach the anachronistic label of feminist to him, he was impatient with the idea that it was ‘laughable’ to take instruction from women. For example, he was nonchalant about his collaborations with the wax sculptor Anna Morandi, whose exquisite anatomical models he used to teach his anatomy class,15 even as some colleagues blanched at the idea that a woman might have anything to teach them.16 Untouched by such prejudices, Galvani attended many of Bassi’s lectures, and soon she and her husband, the medicine professor Giuseppe Veratti, became his mentors.
At the height of his influence, Giambattista Beccaria sent them his textbook, in which he – like Franklin – was beginning to outline his own grand unified theory of electricity. Beccaria cautiously explored the idea that perhaps natural electricity could be present in animals, having read John Walsh’s explosive new publication detailing the anatomy of electric fish. Bassi and Veratti began to encourage their protégés to zap animals with Leyden jars, offering up Bassi’s lab for electrical tests on the hearts, intestines, and nerves of frogs.
In Bassi’s lab, Galvani grew increasingly obsessed. He began conflating animal spirits with the electric fluid in his lectures. In one anatomy talk on causes of death, Galvani claimed it was rooted in the extinction of ‘that most noble electric fluid on which motion, sensation, blood circulation, life itself seemed to depend’.17
While many scholars were beginning to converge on this kind of interpretation, they tiptoed around the conclusion cautiously, loaded as it was with unscientific associations. The more practical problem was that there was no experimental way to test the hypothesis. Still, Galvani was transfixed by the notion that electricity – the stuff in lightning – might be the same mechanism by which God had given breath to man and all other creatures. He was equally transfixed by the notion that he could be the first to discover this facet of God’s beneficence.
So, in 1780, he created a research programme on the role of electricity in muscular motion, and then set about building a home laboratory that would allow him to spend more time on these experiments. The lab contained an electrostatic machine, a Leyden jar, and other more recently invented variants on this electrical equipment.
From there, he began to experiment on frogs. Why frogs? Their nerves are easy to locate, their muscle contractions are easy to see, and can continue up to forty-four hours after the frog has been carved into the grisly configuration that Galvani referred to as his ‘preparation’. Graphic illustrations of the amphibian experiments suffuse all of Galvani’s publications. One shows a frog with its head and midsection almost entirely missing, save for the exposed gossamer strings of the two crural nerves that still connect its legs to its spine.18 In others, the frogs are cut in half below the upper limbs, then skinned and disembowelled. Only their legs remain, joined to each other by a nub of spine. In another, Galvani and his scientific collaborators, Giovanni Aldini (his nephew) and Lucia (his wife) stand in his basement lab, surrounded by dozens of these flayed corpses.
This very particular method of preparing his frogs – from which Galvani never deviated – was inspired by Lazzaro Spallanzani, one of the most important naturalists of the time and Galvani’s frequent correspondent. Spallanzani’s specifications made it extremely easy to distinguish cause and effect. With everything but nerve stripped away, there could be no confusion about what happened when you put electricity into a muscle or nerve.
Galvani started his research with a series of experiments designed to help him understand why electrical current from artificial sources caused muscle contractions. Applying a zap to a muscle obviously caused the muscle to twitch, but by what mechanism? At first he simply repeated previous experiments, touching an electrical contact to various parts of the frog’s body. To send the electricity from the generator into the specific parts he wanted to target, he used wires and other metal objects called arcs, connected to the source of external electricity speared into various parts of the frog.
Usually the results fell in line with his expectations . . . until one day they didn’t. That day, a frog jumped even though there had been no contact between it and a generator. Galvani had been touching the exposed crural nerve of the frog as it lay on its plate. At the same moment, standing about six feet away, Lucia brought her finger close to the machine, which unexpectedly elicited a spark. The frog twitched. Galvani was shocked. In the absence of the usual connections between generator and frog, he could not conceive of any obvious way the electricity could have been transmitted into the dead animal. How could it have twitched without any external electricity to animate it?
No existing hypothesis offered any satisfying explanation, and from that moment on Galvani was ‘inflamed’, as he would later write in his manuscript.19 He began obsessively repeating variations on the experiment, using any available source of ‘artificial’ electricity – Leyden jars, electrostatic generators – and moving the frog by turns closer and farther away. The frog jumped every time.
This led Galvani down a few blind alleys. First he thought there was some kind of atmospheric electricity in the lab that built up in the frog and was then released when the frog’s leg was touched. In 1786, Galvani decided to set up a new experiment to try to get the same result from a different source of electricity. In a somewhat grotesque echo of Franklin’s lightning investigation, he set up the experiment that has come to define him in the public imagination. He hung flayed frogs by hooks from the metal railings of his terrace, their muscles connected to a long metallic wire pointing skyward as black clouds gathered and thunder pealed. Sure enough, the distant lightning had the same effect on the frogs dangling from the metal railing as did the artificial spark: their legs kicked a zombie can-can. (Decades later, this led to Galvani’s enduring nickname of ‘frog dance master’.)
