21.   The Justice Department recently demanded anthrax samples from at least a dozen scientific laboratories to compare them with the deadly bacteria found inside letters mailed last fall.

22.   The suspected anthrax sample is incubated on a culture plate for up to a day, allowing the anthrax to grow.

23.   Then investigators can zero in on anthrax samples from labs in the United States and abroad.

24.   Fort Detrick, which also is home to the U.S. Army Medical Research Institute of Infectious Diseases, has anthrax samples.

25.   Fort Detrick is home of the Army Medical Research Institute of Infectious Diseases, which has anthrax samples.

26.   Fort Detrick, which also is home to the U.S. Army Medical Research Institute of Infectious Diseases, has anthrax samples from other sources as well.

27.   Its success in finding genetic differences between the two anthrax samples was first reported Tuesday by The New York Times.

28.   Labs were asked to detail where and when they got their anthrax samples and to identify labs to which they sent samples.

29.   Until now, no differences among the various anthrax samples had been pinpointed.

30.   According to the report, the coating matches no known anthrax samples, including those produced in Iraq and the former Soviet Union.