NOVA Online (see text links below)
Cancer Warrior
Accidental Discoveries
by Lexi Krock

Accidents in medicine: The idea sends chills down your spine as you conjure up thoughts of misdiagnoses, mistakenly prescribed drugs, and wrongly amputated limbs. Yet while accidents in the examining room or on the operating table can be regrettable, even tragic, those that occur in the laboratory can sometimes lead to spectacular advances, life-saving treatments, and Nobel Prizes.

A seemingly insignificant finding by one researcher leads to a breakthrough discovery by another; a physician methodically pursuing the answer to a medical conundrum over many years suddenly has a "Eureka" moment; a scientist who chooses to study a contaminant in his culture rather than tossing it out stumbles upon something entirely new. Here we examine seven of medical history's most fortuitous couplings of great minds and great luck.

Working scraping bark A laborer scrapes the bark from a cinchona tree. The bark is then sundried and pulverized to make the drug quinine.
The story behind the chance discovery of the anti-malarial drug quinine may be more legend than fact, but it is nevertheless a story worthy of note. The account that has gained the most currency credits a South American Indian with being the first to find a medical application for quinine. According to legend, the man unwittingly ingested quinine while suffering a malarial fever in a jungle high in the Andes. Needing desperately to quench his thirst, he drank his fill from a small, bitter-tasting pool of water. Nearby stood one or more varieties of cinchona, which grows from Colombia to Bolivia on humid slopes above 5,000 feet. The bark of the cinchona, which the indigenous people knew as quina-quina, was thought to be poisonous. But when this man's fever miraculously abated, he brought news of the medicinal tree back to his tribe, which began to use its bark to treat malaria.

Since the first officially noted use of quinine to fight malaria occurred in a community of Jesuit missionaries in Lima, Peru in 1630, historians have surmised that Indian tribes taught the missionaries how to extract the chemical quinine from cinchona bark. In any case, the Jesuits' use of quinine as a malaria medication was the first documented use of a chemical compound to successfully treat an infectious disease. To this day, quinine-based anti-malarials are widely used as effective treatments against the growth and reproduction of malarial parasites in humans.

Jenner vaccinating Phipps A depiction of Edward Jenner vaccinating James Phipps, a boy of eight, on May 14, 1796.

Smallpox vaccination
In 1796, Edward Jenner, a British scientist and surgeon, had a brainstorm that ultimately led to the development of the first vaccine. A young milkmaid had told him how people who contracted cowpox, a harmless disease easily picked up during contact with cows, never got smallpox, a deadly scourge.

With this in mind, Jenner took samples from the open cowpox sores on the hands of a young dairymaid named Sarah Nelmes and inoculated eight-year-old James Phipps with pus he extracted from Nelmes' sores. (Experimenting on a child would be anathema today, but this was the 18th century.) The boy developed a slight fever and a few lesions but remained for the most part unscathed. A few months later, Jenner gave the boy another injection, this one containing smallpox. James failed to develop the disease, and the idea behind the modern vaccine was born.

Though doctors and scientists would not begin to understand the biological basis of immunity for at least 50 years after Jenner's first inoculation, the technique of vaccinating against smallpox using the human strain of cowpox soon became a common and effective practice worldwide.

Röntgen Physicist Wilhelm Conrad Röntgen (1845-1923), discoverer of the X-ray.
X-rays have become an important tool for medical diagnoses, but their discovery in 1895 by the German physicist Wilhelm Conrad Röntgen had little to do with medical experimentation. Röntgen was studying cathode rays, the phosphorescent stream of electrons used today in everything from televisions to fluorescent light bulbs. One earlier scientist had found that cathode rays can penetrate thin pieces of metal, while another showed that these rays could light up a fluorescent screen placed an inch or two away from a thin aluminum "window" in the glass tube.

Röntgen wanted to determine if he could see cathode rays escaping from a glass tube completely covered with black cardboard. While performing this experiment, Röntgen noticed that a glow appeared in his darkened laboratory several feet away from his cardboard-covered glass tube. At first he thought a tear in the paper sheathing was allowing light from the high-voltage coil inside the cathode-ray tube to escape. But he soon realized he had happened upon something entirely different. Rays of light were passing right through the thick paper and appearing on a fluorescent screen over a yard away.

Röntgen found that this new ray, which had many characteristics different from the cathode ray he had been studying, could penetrate solids and even record the image of a human skeleton on a photographic negative. In 1901, the first year of the Nobel Prize, Röntgen won for his accidental discovery of what he called the "X-ray," which physicians worldwide soon adopted as a standard medical tool.

Continue: Allergy

Dr. Folkman Speaks | Cancer Caught on Video
Designing Clinical Trials | Accidental Discoveries | How Cancer Grows
Help/Resources | Transcript | Site Map | Cancer Warrior Home

Editor's Picks | Previous Sites | Join Us/E-mail | TV/Web Schedule
About NOVA | Teachers | Site Map | Shop | Jobs | Search | To print
PBS Online | NOVA Online | WGBH

© | Updated February 2001
Feedback Shop Site Map Search Home Text Version Cancer Warrior Home