Abstract
Bacteriophage 6 nucleic acid was present as a torus after chromic acid-formaldehyde-OsO4 fixation and acetone and propylene oxide dehydration. A herpes virus, infectious bovine rhinotracheitis virus, had its DNA mostly as a torus, collapsed in the centre, or as a network, after glutaraldehyde-OsO4 fixation, but in an uncollapsed torus or network formation after chromic acid-formaldehyde-OsO4. This fixative stabilized nucleic acids, allowing acetone dehydration and plastic embedding without collapse of nucleic acid to the centre of the virion.