THE observations of Dr. N. McAlister Gregg in 1941,1 linking the occurrence of rubella in early pregnancy and the congenital defects resulting in the newborn, stimulated renewed interest in the disease and in measures which might lead to its control. It was not until 1962, however, that recovery of the virus was accomplished by Weller and Neva2 at the Harvard School of Public Health and by Parkman et al3 at the Walter Reed Army Institute of Research. Each group worked independently and used different techniques. At Harvard, the presence of rubella virus was recognized in human amnion cell cultures by the appearance of a subtle cytopathic effect (CPE). At Walter Reed, it was found that rubella virus infected African green monkey kidney (GMK) cells were resistant to the CPE induced by echovirus type 11. These findings were rapidly confirmed by other investigators.4-7 In this report these