SEDIMENTATION OF POLIOMYELITIS VIRUS BY CENTRIFUGATION.

A technic is described whereby poliomyelitis virus may be sedimented by centrifugation for four hours at 18,000 r.p.m. Virus has been recovered quantitatively in the sediment from a 20 per cent., but not a 1 per cent., saline suspension. The addition of 10 per cent. normal serum results in quantitative recovery from a 1 per cent. suspension. Virus has been recovered by intracerebral inoculation from two of four human stools tested by the method described.