Making the desert bloom is but one of the far-reaching achievements of Israel's scientific community.

Driven by necessity — and sometimes by sheer survival instinct — Israeli scientists have made ingenious breakthroughs in agriculture, aviation, medicine and now high technology.

Starting with the pioneering use of drip irrigation to use precious water supplies to nourish the country's dry soil, Israeli researchers tried to make the most of their environment and their own talents. Israel has also been a leader in solar-energy research and seawater desalination, along with the exploration of better ways to protect and bolster crops.

"They had nothing," said Bret Baumgarten, director of business development for Israeli's Economic Mission office in Santa Clara. "They had to look internally. One of Israel's greatest resources is [its] minds."

Fueled in the last decade by the steady flow of Russian immigrants, Israel today has the highest concentration of scientists in the world, according to Baumgarten. In 1995, there were 135 scientists and technicians per 10,000 residents in Israel. The United States, in second place, has 80 scientists per 10,000 people.

Even in the country's early and lean years, Israel achieved some milestones in scientific research.

In the mid-1950s, for instance, researchers at the Weizmann Institute of Science found that testing amniotic fluid taken from a pregnant woman would reveal the gender of the baby she was carrying. This led to widespread use of amniocentesis as a tool for testing for congenital defects.

Recent medical breakthroughs include the creation of Copaxone, a new drug for the treatment of multiple sclerosis. Weizmann researchers Ruth Arnon and Michael Sela were awarded the 1998 Wolf Prize in Medicine for that discovery, along with their development of synthetic vaccines.

Another Weizmann scientist, Hadassa Degani, last year reported that magnetic resonance imaging, or MRI, can diagnose breast tumors without a biopsy. An MRI can help doctors distinguish between benign and malignant tumors by studying the way dye injected into a patient's bloodstream moves through the tumor tissue.

The development of some of the world's first computers in the 1950s set the stage for Israel's current explosion as a high-tech mecca rivaling Silicon Valley. The country has 1,500 to 2,000 high-tech companies with 250 to 300 new firms opening each year, according to Baumgarten.

In 1995, VocalTec developed the first Internet telephone software that allows people to make calls over the Internet. Another firm, Check Point, offers security "firewall" systems to keep outsiders from downloading confidential information over the Internet. Mirabilis Ltd. is making a splash with an Internet chat software system that has reportedly drawn 10 million users.

National security needs turned Israel into a leader in both aviation and military technology, said Jack Kadesh, regional director of the American Technion Society, the fund-raising arm for Technion Israel Institute of Technology. Facing a French embargo on fighter jets to Israel in 1967, Technion researchers designed a superior plane of their own, called the Kfir C-2. Other fighter planes and commercial jets followed. Researchers have also engineered numerous military security devices.

Daniel E. Koshland Jr., a professor of molecular biology at U.C. Berkeley and former editor of Science magazine, has firsthand experience with the pioneering spirit of Israeli scientists. He was organizing an international science meeting in New Hampshire when the Six-Day War broke out in 1967. Several Israeli researchers were scheduled to deliver talks.

"I thought, `Oh, my program is ruined and a lot of those people wouldn't be able to come,'" he recalled. As it turned out, the war ended quickly — and the scientists showed up for the meeting.

"These people went off and fought a war, came back, did their research and went to a conference," he said. "It was very impressive."