“…HeLa cell cultures infected with polio virus contain three forms of virus-specific ribonucleic acid (936). The proteins of Newcastle virus (404), herpes virus (l364), fowl-plague virus (637), vesicular stomatitis virus (651,1354), tobacco mosaic virus (839), adenoviruses (764,1333), and reoviruses (760, 785, 11 72) have been fractionated. Infectious ribonucleic acid from footand-mouth disease virus can be isolated by continuous carrier-free electrophoresis (827).…”