Abstract
Incubation of bacteriophage X174 with isolated bacterial cell walls in tris HCl. MgCl2 solution results in disruption of the phage with partial release of virus DNA. After incubation for 5 min., particles which sedimented heterogeneously at about 50S were formed. These particles were infectious for spheroplasts, but not for whole bacteria. Incubation for 40 min. produced 70S particles which contained less DNA than intact phage. Similar results were obtained when X174 virus particles were incubated with starved bacteria.