Slice of History: Chemotherapy Invented: Aug. 31, 1909

German scientist Paul Ehrlich had already won the Nobel Prize for Medicine the previous year for his work in immunology, but on this day he’s focused on a new aspect of research. He’s hoping to prove his theory that chemicals could be made to target and kill infections within a person without seriously harming the rest of his or her body.

He watches closely as his graduate assistant, Sahachiro Hata, injects a chemical into a rabbit with syphilitic ulcers. Within a day, no living syphilis bacteria can be found in the rabbit and within three weeks, the ulcers have disappeared. It confirms Ehrlich’s contention that chemicals could serve as “magic bullets” to treat diseases. He calls this approach to medicine “chemotherapy.”

In the ensuing months, Ehrlich and Hata did more tests on mice, guinea pigs and more rabbits and, convinced of the chemical’s effectiveness, they began working with a German chemical company to mass produce it. Soon 65,000 free samples were sent to doctors around the world to use in clinical trials. The medication was an instant success and the drug, named Salvarsan, was soon in great demand. It became the most common treatment for syphilis until penicillin became available in the 1940s. The city of Frankfurt named a street in Ehrlich's honor.

But Ehrlich came under fire in some quarters for developing a treatment that critics said promoted promiscuity. And more serious accusations would soon follow. While he made a point of warning about the drug’s potential toxicity if it wasn’t injected directly into a vein—it was, after all, more than 30 percent arsenic—reports were published about patients who were maimed or died at the hands of doctors who failed to administer it properly.

Critics accused him of marketing a dangerous drug with the purpose of getting rich and in 1914, a Frankfurt newspaper went so far as to report that not only was Salvarsan a fraud, but that Ehrlich had tested it on prostitutes against their will. The paper was sued for libel and eventually its publisher was sentenced to a year in prison.

Ehrlich’s name was cleared, but later that year he suffered a stroke. The following year, with Ehrlich reportedly depressed over the escalation of World War I, he had another stroke. This time he didn't survive. Twenty years later, after the Nazis had taken control of Germany, the signs on the street named after Ehrlich were torn down because he was Jewish.

In the U.S., however, he was celebrated in a 1940 movie titled “Dr. Ehrlich’s Magic Bullet.” The screenplay was written by John Huston and one of the movie's stars was Ruth Gordon. The role of Paul Ehrlich, was played by Edward G. Robinson.

In 1970, a crater of the moon was named after him.

More Slices of History

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Theory of Evolution Published: Aug. 20, 1858

Aspirin Created: Aug. 10, 1897

1st Electric Chair Execution:  Aug. 6, 1890

Medicare Is Born: July 30, 1965