Electronmicrography of Murine Poliomyelitis Virus Preparations

Following isolation and identification of the murine strain of SK poliomyelitis virus1in this laboratory, subsequent work has been concerned with purification of the infectious agent. By using physical and chemical methods of extraction and concentration, highly potent virus preparations were obtained from infected mouse brains. These preparations possessed an appreciable degree of physical homogeneity, as determined by ultracentrifugation, and reacted in precipitin tests with specific antiviral serums.2The purified material seemed to offer a good opportunity to gather additional information on the morphologic characteristics of the infectious agent by means of further study with the electron microscope. For the same purpose there were also available tissue culture preparations of SK murine virus. The latter were examined in the unpurified state. sion of the Research Laboratories of the American Cyanamid Company at Stamford, Conn. The instrument employed was the commercial RCA model which permitted primary magnifications between