Induction of Mutations in a Bacterial Virus

In the course of experiments designed for other purposes a paradoxical observation was made: phage λ, inactivated by UV irradiation, when adsorbed onto sensitive bacteria was reactivated when a further dose of UV was given to the phage-bacterium complexes. Among the reactivated phages a fairly large proportion were mutants. A description of these findings and a discussion of their implications will be found below.