A study was performed to determine some properties of the potato virus M (PVM) in crude sap
and in pure preparations. In crude sap the virus was shown to have a dilution end point value of
10- 4, longevity in vitro particles sedimented as one peak with a sedimentation coefficient value of
162 s. The buoyant density in cesium chloride was 1.304 gm/cm ~ Electrophoresis in polyacrylamide
gels showed that the virus possessed only one protein subunit with a molecular weight of 39,300
daltons