The effect of various culture media on infection, growth, lysis, and phage production of B. megatherium.

B. megatherium cells were grown in various culture media, centrifuged and washed, and suspended in other culture media containing "C" or "T" phage. The per cent of infection, rate of growth, lysis, and phage production were determined. The behavior of the system depends on the culture medium in which the cells were grown and also on the culture medium in which they were mixed with phage. With the T phage it is possible to set up systems which yield the following results: 1. No infection, normal growth, no phage production. 2. Infection, normal growth, no lysis) phage production. 3. Infection, growth for several hours, lysis, and phage production. 4. Infection, no growth, lysis, and phage production. The C phage system is less affected by changes in the culture medium. The change in the behavior of the cells with T phage probably is not due to selection since it occurs without much growth of the culture, and is readily reversible.