Abstract
A study of the physical properties of the Nudaurelia and viruses showed the virus to be slightly larger but less dense in CsCl than the virus even though no difference in size or shape could be detected by electron microscopy. Comparative values for the physical properties of the and viruses respectively were: sedimentation coefficient 213 and 217S, diffusion coefficient 0.97 and 0.79 x 107 cm2/s, buoyant density in CsCl 1.30 and 1.28 g/ml, and diam. in the electron microscope 39 to 40 nm for both viruses. All preparations of virus included small amounts of virus antigen with a buoyant density of 1.33 g/ml.
* Present address: State Vaccine Institute, Pinelands, 7405, South Africa.