Abstract
Bacteriophages are viruses that specifically infect bacteria. They were discovered independently by Twort in England and d'Herelle in France (1). d'Herelle and his colleagues demonstrated the bacteriophage to be a self producing organism; a virus which infects sensitive bacteria and causes lysis of its host (2). | It was subsequently revealed by investigators that there was another possibility of phage-cell interaction distinct from that proposed by d'Herelle (3, 4, 5). Instead of the sensitive host being lysed, it was determined that some bacteria possessed the capacity to give rise to, and maintain, a phage producing clone in the absence of free bacteriophage. Andre Lwoff defined this hereditary power to produce bacteriophage as lysogeny. A lysogenic bacterium thus is one that possesses and transmits the power to produce bacteriophage (2). | The lysogenic state is considered stable, but a small amount of free phage can be observed in a growing culture of lysogenic bacteria. Each cell in the culture has a small probability of undergoing some change that may upset the phage-host relationship. The result is the lysis of the host cell and the release of mature, infectious phage. This phenomenon is known as spontaneous induction.