Now that the electrophoretic mobility apparatus has been assembled and tested, measurements will be made of the electrophoretic mobility of Sindbus virus and EMC-1 virus and Factor VIII as a function of pH, ionic strength and buffer type. Then, to provide baseline data, electroultrafiltration runs will be made using buffer containing only the single viruses to determine the field strength required to prevent the virus from reaching the ultrafiltration membrane. The separation of the viruses from Factor VIII solution will then be investigated. The electrophoretic mobility apparatus will be used in the Hepatitis Laboratory to measure the mobility of the Dane particle and the virion as a function of the important variables of the separation. From the work with the innocuous viruses, conditions will be chosen for separation of the infective particles from Factor VIII solutions. In this period, studies will also be carried out of the separation of albumin and Factor VIII from normal plasma, to ascertain the utility of the new technique to perform these separations faster than with present technology.