The reported discovery of living bacteria in ancient rocks buried deep under Virginia evokes memories of bitter disputes after similar reports in the past. Mindful of this history, the experimenters have resorted to heroic efforts to avoid contamination.

In the 1960s, Bartholomew Nagy of Fordham University and colleagues reported extracting five types of "organized elements," resembling fossil bacteria, from within a meteorite that had fallen on France in 1864.There was a rush to examine other meteorites of this type, and researchers around the world began reporting that they had found similar fossils or life's precursors.

Among them were Melvin Calvin, a Nobel laureate at the University of California in Berkeley, and colleagues who said they had found what seemed to be biological building blocks in meteorites. Another Nobel laureate, Harold C. Urey of the University of Chicago, urged that the reports be taken seriously.

Nagy pointed out that his examination of the French meteorites had sought valiantly to avoid contamination. Before a sample of the interior was extracted and studied, the equipment was cleaned with acid and baked in a vacuum, or kept red-hot for an hour.

Frederick Sisler, working in the Germ-Free Laboratory of the National Institutes of Health, said he was also culturing bacteria from a meteorite. All sides of the specimen's exterior were sterilized by exposure to intense ultraviolet light. The meteorite was then soaked in hydrogen peroxide to wash off dirt, held briefly over a flame and plunged into a germicidal solution.

In 1963, these and earlier reports were finally discredited when Edward Anders of the Enrico Fermi Institute for Nuclear Studies at the University of Chicago and a colleague showed that the most lifelike of Nagy's specimens were actually ragweed pollen grains.

Of the new claim, Anders, reached at his home in Switzerland, said he found it "quite intriguing."

To avoid contamination this time, the Department of Energy group took measures similar to those applied to rocks brought back from the moon in 1969. Those specimens, and for a time the astronauts themselves, were quarantined in a special building at the Johnson Space Center in Houston.

The purpose was not only to see that no earth bacteria invaded the specimens before analysis, but to prevent the escape of any brought from the moon.