The Spark of Life: Electricity in the Human Body (39 page)

Competing to ‘electrify’ New York city in the late 1880s were, on the one hand, Thomas Edison and, on the other hand, George Westinghouse and Nikola Tesla. Edison advocated the use of direct current and his Electric Light Company, in which his fortune was invested, was set up using DC power (at 110 volts). Unfortunately, power transmission at 110 volts is very inefficient and the voltage drops off so rapidly that each house would have to be within a mile or so of a power station – hence many power stations would have been needed to light New York. Increasing the thickness of the copper supply wires allowed the current to be increased without the wire melting but at a considerable economic cost. The other possibility would have been to make the transmission voltage more than 110 volts. However, this was not an option because there is no way to easily drop the high voltage to a lower one in a DC system. This fact also necessitated supplying different power lines for equipment that ran at different voltages. Imagine if different circuits were needed to power your washing machine, electric kettle and computer, and you will appreciate how inconvenient that would be.

Tesla contended that an AC system was a better option, and invented a means of generating and supplying AC power that was bought by Westinghouse’s company. The advantage of this system was that electricity could be supplied at very high voltages in the distribution cables, so enabling it to be transmitted over long distances with less loss of power. It could then be stepped down to a lower (and safer) voltage at the house. Many fewer power stations were therefore needed, and only one power line to each home was required, as transformers could be stationed within the house to supply voltages at different levels.

The advantages of the Tesla/Westinghouse system quickly became obvious. Edison counter-attacked by arguing that AC current was highly dangerous and staged a series of gruesome public executions to prove it. In front of a large press audience, a stray cat or a puppy was placed on a sheet of tin and subjected to 1,000 volts from an AC generator – with predictable results. In one instance, the executioner almost electrocuted himself, being blown across the room by the shock, his body ‘wrenched apart as though a great rough file had been pulled through it’. Seeking greater publicity, Edison electrocuted the elephant Topsy. It also did not escape his notice that a person would provide even better propaganda.

Old Sparky

On 6 August 1890, the New York prison authorities executed the condemned murderer William Kemmler using the electric chair. It was the first time it had been used and it was not a success. The first shock was too weak and failed to stop his breathing, so that the current had to be switched on for a second time. As the
New York Times
wrote, ‘it was an awful spectacle [. . .] far worse than hanging [. . .] so terrible that words fail to convey the idea’.

The background to the story was that the state of New York had been endeavouring to find a means of capital punishment that was more humane than hanging. A member of the commission appointed to look into the matter, Dr Alfred Southwick, recalled having seen an intoxicated man die a quick and seemingly painless death after accidentally touching a live wire. The commission reported that electrocution was a possible solution, and on 1 January 1889 the state passed a law allowing the use of an ‘electric chair’ as a way of killing convicted criminals. There was just one small problem: no electric chair existed.

The state legislature did not specify whether AC or DC electricity should be used and left it to a committee to decide. Edison actively campaigned for AC current to be used, surmising the public would therefore not want it in their homes. He employed Harold Brown and Dr Fred Peterson to design an electric chair, and to carry out further public executions of dogs, calves and a horse using AC current, which generated considerable publicity. Given that Peterson was also on the government committee that selected the best method of electrocution, it is perhaps not surprising that AC current was finally chosen for the electric chair, thereby coincidentally stigmatizing it as too dangerous for domestic use.

Edison and Brown had to obtain the AC generator they needed by subterfuge, as the Westinghouse company refused to sell one to the prison for the purpose. Westinghouse, seeing his business interests endangered, protested that electrocution was a cruel and inhumane punishment and paid for Kemmler’s appeal against the mode of execution. Edison was summoned as an expert witness for the state. The appeal was lost and Kemmler was electrocuted. However, the current was insufficient to cause instant death, and Kemmler was simply roasted. It was a far more agonizing way to die than hanging.

The electric chair works by stopping the heart or frying the brain. The prisoner is strapped into the chair and wires are attached to the skin by surface electrodes moistened with a conducting salt solution. A massive electric shock is applied that causes instant brain death, and subsequent bouts of current are used to ensure that the other organs are fatally damaged. Although it remains a legal form of execution in a number of states in the USA, it is rarely used today, lethal injection being the preferred means of capital punishment.

Edison may have been a great inventor and a brilliant businessman, but he was not without flaws, and his advocacy of the electric chair was far from glorious. It is ironic that he once boasted, ‘I am proud of the fact that I never invented weapons to kill,’ and that he supported non-violence towards animals. It also seems somewhat strange that Edison is fêted as the man who gave us universal electric light and power, given that it was the AC system that was finally adopted. A US hero, following Edison’s funeral President Hoover requested that North Americans dim their lights for one minute as a tribute to his memory. By contrast, Tesla, who actually invented the national grid, is a largely forgotten genius.

Phasers on Stun

Society has often dreamt of a weapon that can temporarily incapacitate an individual, instantly stopping them in their tracks without causing pain or lasting harm. The ‘stun’ mode of the famous phasers used in the TV show
Star Trek
is just one of many fictional examples.

The latest real electric stun gun is the Taser. It works by stimulating your nerves so much that your muscles contract uncontrollably and you fall over, usually within two to three seconds. The Taser fires two small darts that are connected to a handheld gun by long fine cables. The darts pierce clothing and penetrate the skin, where they then serve as electrodes, conducting an electric current from the gun to your body. The stimulus causes your muscles to contract, incapacitating you for as long as the electric current continues to flow. It also hurts, because the electric current stimulates your pain nerve fibres. Indeed, it is not easy to say how it would be possible to make a device that stimulates your motor nerves, thus preventing movement, without also affecting your sensory nerves and causing pain. After allowing himself to be tasered in an effort to persuade the UK government to issue police officers with Tasers, Greater Manchester’s Chief Constable said, ‘I couldn’t move, it hurt like hell. I wouldn’t want to do that again.’

Tasers are now widely used by police forces to control violent people, or those suspected of being about to cause violence. Their use is not without controversy as a few people have died as a result of being tasered. Some people may simply be more susceptible to the electric shock, but others may have received a greater electric current because they happened to have a naturally lower skin resistance, or were wet when tasered.

Emotional Signals

As everyone knows, when you are very nervous you become hot and clammy and the palms of your hands get damp. Some people even break out in beads of sweat. This is because the brain responds to stress by increasing the activity of the sweat glands in your skin. The salty fluid they secrete decreases the resistance of your skin and this can easily be detected simply by seeing how readily a small electric current – so small that you don’t feel it at all – passes through the skin. Skin resistance is highly sensitive to many emotions, including fear, anger and stress, and thus changes in skin resistance have been used to detect emotional changes in an individual. The psychoanalysts Carl Jung and Wilhelm Reich, for example, used it as a tool to help reveal their patients’ emotional state.

Changes in skin resistance also form the basis of the polygraph lie detector, which measures the electrical resistance of the skin, the logic being that telling a lie will make you nervous. As might be expected, this system is not without flaws, as simply taking the test makes some people nervous while a hardened liar might not flinch.

Fascinatingly, the Church of Scientology uses similar technology in its ‘E-meter’, a pastoral counselling device that is stated to measure ‘the electrical characteristics of the static field surrounding the body’ and detect the subject’s mental state. The E-meter became the subject of a major Food and Drug Administration investigation in 1963, following concerns that the Church of Scientology was using it to practise medicine without a licence, and that false claims were being made for its efficacy in treating various physical and mental illnesses. After prolonged litigation involving trial, appeal and retrial, the verdict was that the E-meter could only be used for religious counselling and that it should carry a warning stating it was not useful for the diagnosis, treatment or prevention of any disease. Not surprising, perhaps, since it is, after all, only a device for measuring skin resistance.

Mind Control

Electrical devices may have been used to kill, incapacitate or as instruments of torture and coercion, but they have also been used for good. Sometimes, as in the case of electroconvulsive therapy, the effects are controversial. But electrical devices are getting more sophisticated. Once we understand what the electrical activity of a cell or tissue looks like, it is often possible to provide an artificial stimulus that is an exact replica of the normal waveform to replace or correct a defective signal. Heart pacemakers have enabled many thousands of people to lead normal lives and implantable defibrillators have helped hundreds more.

The ability to control another person’s brain remotely, to force them to behave in a specific way, is the stuff of nightmares, albeit perhaps the Pentagon’s dream. Yet it is not impossible to control another creature’s behaviour simply by stimulating the correct bit of the brain. José Manuel Rodriguez Delgado was sufficiently confident of this idea that in 1963 he stepped into a bullring in Cordoba in front of an aggressive fighting bull. As it charged towards him, Delgado stood his ground and calmly twiddled a button on a remote control device that sent a signal to a transceiver connected to an electrode implanted in the animal’s brain. Electrical stimulation of the caudate nucleus stopped the bull in its tracks: it skidded to a halt within a few feet of the scientist.

Similarly, stimulating the brain of a fruit fly either with electric current or by photoactivation of light-sensitive ion channels can affect its course of action: as we saw in Chapter 11, it can cause a female fly to behave like a male one. Direct electrical stimulation of the human brain can have equally dramatic effects. Surgeons operating on the brain to remove a tumour, or tissue that is responsible for triggering an epileptic seizure, sometimes apply a small electric current to test that the tissue they are about to remove is not of vital importance for the patient. Such stimulation can provoke memories, sensations and even feelings of pleasure or fear. The right amount of current applied at the correct place can even be of immense therapeutic value. In some cases, the effects are so beneficial that electrodes have been permanently implanted in the patient’s brain.

Parkinson’s disease is a debilitating condition in which patients develop an involuntary tremor, muscle stiffness and difficulty in walking and talking. In some people the tremor is so bad that their arms windmill around wildly. Deep brain stimulation is now widely used to alleviate tremors that cannot be controlled by drugs. It involves electrically stimulating specific groups of nerve cells deep within the brain, usually in an area known as the subthalamic nucleus that is involved in controlling movement. The device used to do this is similar in concept to a cardiac pacemaker, and involves an electrode implanted in the brain connected by insulated wire to a small stimulating unit outside the body. A small hole is drilled in the skull and an electrode is inserted into the brain of an awake patient under local anaesthesia. The patient actively helps the surgeon decide whether the electrode is placed in the correct position by reporting what he feels when the stimulator is switched on and electrical pulses are applied to the brain. Once the electrode is in the correct position, the matchbox-sized stimulation unit is implanted under the skin, near the collarbone. Electrical impulses can then be sent from the stimulator to the electrode within the brain: usually continuous stimulation at a frequency of 150 pulses per second is used.

Deep brain stimulation suppresses the activity of the subthalamic nucleus of the brain. Quite how it does so is debated. One idea is that it stimulates the firing of inhibitory neurones that switch off overactive nerve cells: another is that it disrupts pathological brain rhythms. However it works, it is remarkably effective. Patients whose bodies are shaking uncontrollably appear normal the instant the device is switched on. Michael Holman, a journalist with the
Financial Times
, described it thus: ‘It could not have been simpler or starker. At the touch of a button, the battery-operated stimulator implanted in my chest was turned off by the doctor in charge of my assessment. My tremor returned within seconds, steadily gathering force. In a couple of minutes I was shuddering and flopping hopelessly. Another touch of the button, and I was restored to my tremor-free state.’