Word: schwerdt
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Dates: during 1950-1959
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...biochemists at the University of California, Drs. Howard L. Bachrach and Carleton E. Schwerdt, did it the hard way.'They grew polio virus of the Type II or Lansing strain in the nerve tissues of rats, and got the concentration up to about 10%. This preparation contained particles of two sizes, some a millionth of an inch in diameter, the others less than half as big. The researchers separated the two kinds in an ultracentrifuge. then they injected the materials into different groups of rats. Only the animals that received the millionth-of-an-inch particles caught polio. That...