Another scientist who has examined samples of yellow rain for the government questioned Meselson's whole approach to the issue.

University of Minnesota plant pathologist Chester J. Mirocha said that Meselson's findings were irrelevant to the whole debate, because the samples of leaves containing mycotoxins did not have the yellow spots which resemble bee feces.

"What I see Matthew Meselson working as is not as a scientist, but as a politician," Mirocha said. He added that in fact Meselson has tried to make facts fit his hypothesis.

Defense

Responding to these changes, Meselson said. "It's a shame to see Mirocha lower himself to ad hominum attacks."

He added that he has published all his work on yellow rain thus far in scientific journals and plans to do the same for his new findings.

"If that's not science, I don't know how to do science," he added.

Meselson repeated his contention that adequate scientific surveys have not yet been carried out to test for mycotoxins.

He added that he and Seeley brought back samples of bee feces and foods to test for such substances--which would be further proof in his mind that they cause the yellow rain.

Part of the problem in getting the State Department to change its position on the subject--even if it is proved wrong--is the heavy stake they have put into their charges against the Soviets.

A change in position could diminish American credibility around the world--a political fact Meselson is well aware of.

"Once the President of the United States and the Secretary of State have said there is chemical warfare, no amount of scientific evidence" can change the U.S. position, he said