Did a Danish veterinarian first invent the defibrillator or the electric chair, or both? In 1775, when people were beginning to mess around with electricity, Peter Abildgaard paved the way for the formal use of electricity to both end and recover life.
The Frankenstein movies and modern medical dramas have tied electricity to life and death so inextricably that it's not unusual for people to think that they can jump-start a heart the way they jump-start a car. This is not so. Defibrillation will work under a specific set of conditions to re-establish regular heart rhythm, but hooking up a car battery to a dead person will do nothing. Even death is harder to come by than we imagine - the electric chair had to be carefully calibrated and its early history is full of gruesomely prolonged executions.
That doesn't mean doesn't mean that the connection between electricity, life, and death, are made up exclusively by Hollywood. Although Mary Shelley didn't use lightning to give life to the monster in the original version of Frankenstein, the use of electricity to give life to lifeless flesh was a common idea. Throughout the 1700s, physicians and carnival barkers alike conducted public demonstrations in which they made dead frogs' legs twitch, entire oxen convulse, and even seemed to give new life to the heads of executed prisoners with electricity. These people contributed to the interest in electricity, and to scientific knowledge on the subject, but it was a Danish veterinarian who first demonstrated the use of electricity in a medical context.
Being a vet, Peter Abildgaard didn't use a human subject. Instead a hapless chicken was the first experimental subject. Details of the experiment vary, but the gist is the same. One shock takes the bird out, and the next one brings it back. Abildgaard used evocative, if inexact language. He wrote that the first shock of electricity caused the bird to be "rendered lifeless." Some took this to mean that the bird was stunned, and others believed that it was dead. No one was surprised that a bird could be killed by electricity. Lightning had always been around and people knew what happened to people and animals who were hit by it. The exact state of the chicken does have some bearing on the fact that next shock, according to Abildgaard, returned the chicken to its senses. Although electricity had been shown to make muscles move, it wasn't considered a serious medical treatment.
Abildgaard's paper on the subject said that he repeated the process a few times, and that the hen appeared stiff and sick for a day, but was back to laying eggs the day after. Other accounts say that after the first shock brought it back to consciousness the chicken made a run for it and couldn't be captured (if so, who could really blame it?), and that the experiment was repeated with other chickens. Either way, it got people thinking of what practical medical use electricity could be. Although defibrillators did't come into regular use for nearly another two hundred years, it was said that the people of the 1700s did try reviving someone with an electric shock once, and managed it successfully. In 1788, a three-year-old girl had a fall that, as people would say, rendered her lifeless, and an application of electric shock revived her. Whether this was an actual, successful medical defibrillation or whether they were just electrocuting a patient who would have recovered anyway, no modern person can say. But it all goes back to a vet and a brave, or crafty, chicken.