Sensitivities of different bacteriophage species to ionizing radiations.

where S is the survival ratio (number of plaque forming phage particles after exposure to a dose D of radiation) /(number of plaque-forming phage particles before exposure), and R is the radiosensitivity of the phage (for a recent discussion of this subject, see Pollard, 1954). The radiosensitivities of a number of bacteriophage species have been measured, and are presented here and compared with data available in the literature, as a contribution to phage taxonomy and as a possible help in the choice of material for future investigations.