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SIX MEN IN LONDON

The Discovery of a New Disease and Its Causes

The unhappy sufferer has considered [the disease] as an evil, from the domination of which he had no prospect of escape.

—Dr. James Parkinson, “An Essay on the Shaking Palsy,” 1817¹

AT THE TURN OF THE NINETEENTH CENTURY, BRITAIN WAS booming and its Industrial Revolution was about to transform the world. Coal mining fueled James Watt’s steam engine. Iron smelting enabled the building of new bridges, while steamships and the telegraph linked disparate lands. The spinning jenny churned out wool and cotton, gas lights illuminated theaters, and author Jane Austen challenged social norms. Populations soared, and London, the epicenter of all of it, exploded with prosperity.²

The city was also becoming filthy. Humans and factories dumped their waste into the River Thames. Poor sanitation and overcrowding spread infectious diseases, including cholera, typhus, and tuberculosis. With the new industries came new chemicals and pollutants spewing from what the poet William Blake called “dark Satanic mills.”³

According to one environmental researcher, “It’s difficult to fully capture just how polluted London’s air was throughout the 19th century.”⁴ These industrial London fogs (Figure 1) were “often so dense that they… interrupted general economic activities, and even contributed to [the city’s] becoming a breeding ground for crime.”⁵ It was on these hazy streets that a seasoned physician observed something new.

FIGURE 1. Illustration of London fog, 1847.

A BRIEF HISTORY OF PARKINSON’S DISEASE

A suffragist, activist, paleontologist, and advocate for the mentally ill, Dr. James Parkinson had many lives.⁶ Because of his politically radical stances, he used pseudonyms and, at one point, narrowly avoided imprisonment for his alleged role in a plot to assassinate King George III.⁷ However, his most enduring contribution to humanity was not his politics but a single essay that was destined to become a medical classic.

In 1817, Parkinson was a local doctor in Hoxton Square, London, where, almost two hundred years earlier, William Shakespeare had crafted many of his plays. Parkinson’s literary contribution was titled “An Essay on the Shaking Palsy.” By this time, he already had a wealth of clinical experience, gathered over more than thirty-two years of patient care.⁸ In his essay, Parkinson described six men, three of whom he had simply noticed on the street, who all shared similar characteristics—tremors, a bent posture, an abnormal walk, and a tendency to fall.⁹

Although ancient Chinese, Egyptian, Greek, and Indian texts provide rare depictions of some of these same symptoms, Parkinson’s essay was the most substantive.¹⁰ As he indicated, tremors had long been known and had multiple causes. However, the multi-symptom affliction that Parkinson was now observing on his walks had yet to be classified.¹¹ His essay was well received, but its importance would not be recognized for decades.¹²

Fifty years after James Parkinson’s essay (Figure 2), Dr. Jean-Martin Charcot, the famous French neurologist, called the disorder “la maladie de Parkinson,” or Parkinson’s disease.¹³ Charcot added slow movements and stiffness to the list of key features.¹⁴ He also noted that not everyone with Parkinson’s disease had a tremor.

By the end of the nineteenth century, the clinical features of Parkinson’s disease were well known. In his 1892 medical textbook, Sir William Osler, the father of modern medicine, wrote, “When well established, the disease is very characteristic, and the diagnosis can be made at a glance.”¹⁵ While the external features of Parkinson’s were obvious, the underlying biological alterations were not.

THE ROLE OF DOPAMINE

What Parkinson and Charcot could not have observed in their time were the changes occurring in the brains of their patients. Scientists had long overlooked, downplayed, and ignored the chemical dopamine. But Dr. Arvid Carlsson, a Swedish pharmacologist working in the 1950s, saw dopamine differently.¹⁶ In experiments, he established that dopamine allowed nerve cells to communicate with one another. In other words, it was a neurotransmitter.

Carlsson also showed that a brain region important for movement contained high levels of dopamine. To demonstrate the chemical’s importance, he gave rabbits a drug that lowered dopamine levels in the brain. The rabbits lost their ability to hop and simply lay down. When they were given levodopa, a drug that is converted by nerve cells into dopamine, the rabbits regained their bounce.¹⁷