The middle-aged lady is running frantically down the beach, waving her arms at the lifeguard: "Help, help!" she cries. "My son the doctor is drowning!"

It's a joke, from maybe a generation ago, based on the idea that every Jewish mother wanted to rear a doctor son and would brag about it until the day she (or, apparently, even he) died — which, it turns out, is based on an even older obsession: Jews and medicine.

I grew up with two doctor uncles in my (Jewish) family, so I always knew that the religion and the profession went together like chicken and soup — at least in America in my lifetime. But a new exhibit at the Yeshiva University Museum in New York showed me just how far back the two are twined — back at least to medieval times. And what's remarkable is that Jews were drawn to medicine even as medicine was actively rejecting the Jews.

One item on display is the note from a university official who interviewed a Dartmouth grad applying to Columbia's medical school in 1933. The applicant, he wrote, was smart and funny and "probably Jewish — but no unpleasant evidence of it." That was in 1933, when quotas made sure that no more than 5 percent of the student body was Jewish.

And it's not as if things were better in earlier centuries. During the Middle Ages on through the Renaissance, most European medical schools would not accept Jews at all. One exception was the school in Padua, Italy, which did — but charged them extra. And then there's the 1598 papal decree, also at the exhibit, that declared that no Catholic should seek the services of a Jewish doctor, even though that's what most popes did.

What's remarkable is that though the medical establishment wasn't keen on Jewish doctors, that very prejudice ended up producing some of medicine's greatest leaps forward. How?

Well, as enlightenment crept over Europe and Jews gradually were admitted to its institutes of higher learning in the 1800s and 1900s, there were still some barriers. "Certain fields were less open to them," said Yeshiva's guest curator, Josh Feinberg, "like surgery, for example." More open were the newer, less prestigious fields of dermatology, neurology, immunology, pathology, psychiatry and gynecology. And those are where Jews made their mark.

People I never heard of changed medicine — and our lives — forever. Ferdinand Cohn (1828-98) was the founder of microbiology. Two guys — Bernhard Zondek (1891-1966) and Selmar Aschheim (1878-1965) — came up with the first pregnancy test, and August von Wassermann (1866-1925) came up with the first test for syphilis. Paul Ehrlich (1854-1915) was the first guy who cured it. His "compound 606" — there's a rusty vial of it at the show — was the most effective treatment for that disease until the advent of penicillin in the '40s.

It was Ehrlich, by the way, who coined the term "magic bullet." His goal was always to discover a medicine that killed the parasites but didn't hurt the rest of the person. That dogged pursuit led him to become the father of chemotherapy and a Nobel laureate in 1908. (It took another six years for his employer, the University of Frankfurt, to make him a full professor.) His phrase also led to the title of the exhibit, "Trail of the Magic Bullet."

The trail led through more hardships, such as the ones faced by Russian-born Waldemar Haffkine (1860-1930). The promising young researcher couldn't become a professor unless he renounced his Judaism. Instead, he left the country. Eventually, he ended up in India, where he administered the world's first vaccines for cholera and the bubonic plague — vaccines he'd discovered and tested on himself. Between 1893 and 1894, he went village to village, inoculating 25,000 people and reducing the death rate by 70 percent.

Maybe he'd have been just another doctor if he'd been allowed to remain a Jew back home.

This is not to say prejudice is a force for good. No, it's to say that when there is a drive for good — in a person or a people — sometimes it is very forceful despite the odds. And that is good for us all.

Lenore Skenazy is the author of "Free-Range Kids: How to Raise Safe, Self-Reliant Children (Without Going Nuts with Worry)" and "Who's the Blonde That Married What's-His-Name? The Ultimate Tip-of-the-Tongue Test of Everything You Know You Know — But Can't Remember Right Now." To find out more about Lenore Skenazy ([email protected]) and read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate Web page at www.creators.com.