Isolation and study of a bacteriophage of Bacillus pumilus

The phenomenon of bacterial lysis by viral action was first reported by Twort (1915) and shortly after, D'Herelle (1926) described the concept of bacteriophagy. Contemporary writers tended to regard the two reports of lysis as due to the same phenomenon. This practice met with disapproval by D'Herelle who felt that Twort's failure to report "complete lysis or dissolution" of the bacterium set the letter's observations apart from "true bacteriophagy" as described by D'Herelle (1926).